A Qualitative Systematic Review on the Perceived Effects of Air Pollution on Respiratory Health Outcomes among Adults Aged 40-60 in Urban Areas of the UK

Abstract

Aim

The research study has focussed on analysing the effect of air pollution on respiratory health of people (40-60 years) in the urban regions of UK. 

Background

Air pollution has been observed to have an increasing impact on public health in the urban regions of UK. This is because of the fact that urban areas are more exposed to vehicle usages followed by fossil fuel burning and industries, that cause air pollution.

Middle aged and elderly people have mostly been observed to have a weaker respiratory system, especially who have recovered from COVID 19 infection. A research on the effect of air pollution on respiratory health of people of the above mentioned age group was thus conducted. 

Method

Secondary research design (qualitative systematic review) was selected as the most significant research design in order to reach the research goal. Data collection was performed from authentic databases. A total of 11 papers were selected from the complete list of articles, available as the search results of the respective databases. Thematic analysis was performed to address the study objectives. 

Results

The perceived respiratory effects were mainly comprised of deteriorated lung function, breathing problems and COPD. Associated respiratory effects included CVD and other health outcomes. 

Conclusion

Policies and recommendations should be made from the government in UK, in order to control the heightened air pollution levels and deleterious health effects on human beings. 
Keywords: Air pollution, COPD, Lung disorder, UK 40-60 year old population, Middle aged people, Respiratory health, Health outcomes. 

Chapter 1 - Introduction

1.1.Rationale for the Research Topic

1.1.1. Background on Air Pollution and Health:

Across the globe, air pollution stands as a formidable adversary to public health. Emanating from industrial activities, vehicular emissions, and other anthropogenic sources, these pollutants have been consistently linked to a myriad of health complications. Among these, respiratory ailments have particularly drawn attention.

Inhalation of polluted air, laden with particulate matter and noxious gases, directly affects the lungs and respiratory passages (Landrigan 2017). Chronic exposure has been associated with conditions such as asthma, chronic obstructive pulmonary disease (COPD), and even lung cancer (Kurt et al. 2016).

With the World Health Organisation (WHO) estimating that approximately 4.2 million premature deaths annually can be attributed to ambient air pollution, the gravity of this health crisis becomes palpable. (Vohra et al.,2021)

1.1.2. Specific Focus on the UK:

The United Kingdom, with its rich industrial legacy and dense urban conglomerations, presents a unique case in the discourse on air pollution. Urban areas, such as London, Manchester, and Birmingham, have frequently grappled with elevated levels of pollutants, especially during peak traffic hours or due to industrial emissions (Atkinson et al.,2013).

These urban centres were observed to have been affected by moderate levels of air pollution, exacerbating respiratory health concerns for their denizens. Reports suggest that air pollution contributes to approximately 40,000 premature deaths in the UK annually (Pimpinet al., 2018). Such statistics underscore the urgency of addressing this issue within the UK's context, particularly in its bustling urban landscapes.

1.1.3. Importance of the Age Group 40-60:

The age bracket of 40-60 holds unique significance in the context of air pollution-related health outcomes. As individuals advance into middle age, physiological changes render the respiratory system more susceptible to environmental pollutants (Pimpin et al., 2018). Cumulative exposure over decades can lead to the onset or exacerbation of respiratory conditions (Mansalidiset al.,2020).

Furthermore, the middle-aged population often represents a segment that has been exposed to changing air quality standards over their lifetime, providing a rich temporal perspective on the health impacts of air pollution (Lave and Seskin, 2013). Investigating the vulnerabilities and experiences of this age group not only offers insights into the immediate health implications but also aids in forecasting potential long-term public health challenges.

1.2. Research Question

In the vast realm of public health research, elucidating the intricate relationships between environmental factors and health outcomes remains paramount. Within this context, this systematic review seeks to address the following pivotal question: 

"How does exposure to air pollution in urban areas of the UK influence the respiratory health outcomes of adults aged 40-60, as perceived through their personal narratives and experiences?"

The RQ has been formatted by following a PEO format – Population Exposure Outcome framework.
P – 40 – 60 years old people in UK
E – Air pollution
O – Outcome (health effects) 

1.3. Relevance to the Wider Public Health Field

1.3.1. General Impact of Air Pollution:

Globally, air pollution has emerged as one of the most pressing public health concerns. Its tentacles stretch across continents, affecting both developed and developing nations. Kelly and Fussell (2015) identified air pollution as the world's largest single environmental health risk, causing millions of premature deaths annually. From respiratory to cardiovascular complications, the health repercussions of polluted air are multifaceted and severe. As urbanisation accelerates and industrial activities proliferate, the quality of air continues its downward trajectory, making it an issue of universal concern in the public health domain (Turner et al.,2020).

1.3.2. Implications for Healthcare Systems:

The health ramifications of air pollution invariably translate into burdens for healthcare systems. Respiratory diseases, exacerbated by pollutants, lead to increased hospital admissions, prolonged treatment regimes, and, in severe cases, intensive care interventions(Landrigan, 2017). This increase in healthcare demand puts a strain on medical facilities, from general practitioners to specialist respiratory clinics.

The financial implications are equally daunting. With escalating treatment costs and prolonged medical care, healthcare budgets misbalances, affecting both individual pockets and national coffers (Kurt et al.,2016). Furthermore, the chronic nature of many pollution-induced respiratory conditions means long-term care, further stretching already disrupts the balance of healthcare resources (Kurt et al.,2016).

1.3.3. Societal and Economic Impacts:

Beyond the immediate health implications, the societal and economic repercussions of compromised respiratory health in urban populations are profound. Affected individuals often face reduced productivity, absenteeism from work, and, in severe cases, early retirement – all of which have economic implications (Horton et al.,2023).

The societal fabric is strained as families grapple with the emotional and financial stresses of caring for affected members. Moreover, as cities become get polluted with air, their business, tourism and residence levels can reduce. Thus, the ripple effects of compromised respiratory health in urban settings extend far beyond individual suffering, impacting broader societal structures and economic vitality.

1.4. Justification for a Systematic Review

Research in public health, due to the multidisciplinary character of the field itself, makes use of a wide variety of research methodologies that are adapted to answer specific questions. Quantitative research techniques, such as randomised controlled trials and cohort studies, can provide numerical insights and often centre on causation and risk (Bowling, 2014).

Interviews and focus groups are two examples of qualitative research methodologies that dive into the subtleties of human behaviour in addition to personal experiences and impressions (Berghset al.,2016). In addition, research using mixed methodologies combines the two methods in order to produce a deeper and more comprehensive grasp of the topic (Hansen, 2020). The choice of methodology, despite the fact that each approach is strong in its own right, is determined by the character of the research issue and the outcomes that are desired.

A systematic review stands out as a light of comprehensiveness and rigour in the broad expanse that is academic research. Systematic reviews, as opposed to typical literature reviews, adhere to a rigorous methodology, which guarantees an extensive search of the existing literature, clear selection criteria, and a robust assessment of the quality of the studies that are included in the systematic review (Papaioannou et al.,2016).

This methodical technique makes certain that a systematic review takes into account all of the information that is currently known about a certain subject, both in terms of its breadth and its depth (Thomas et al.,2020). Additionally, a systematic review might give more decisive insights since it synthesises the data from several research, so typically reducing the biases that are inherent in individual investigations (Chen, 2017).

This strategy becomes beneficial when used to subjects that have been the subject of a myriad of individual studies since it provides a condensed picture as well as highlights areas of consensus or controversy among the scientific community (Munn et al.,2018).

For the issue at hand, which aims to get an understanding of the effects that air pollution has on respiratory health among individuals aged 40-60 living in metropolitan regions of the United Kingdom, a systematic review appears as the most appropriate research strategy to use. In light of the fact that personal narratives and experiences are of a qualitative character, it is of the utmost importance to compile and evaluate the many voices and tales that are presented in the literature (Bolan et al.,2017).

Individual qualitative studies, despite their wealth of information, typically have small sample sizes and may be dependent on the environment in which they were conducted.

These individual narratives may be compiled into a more comprehensive and accurate picture of the lived experiences of the target population through the use of a systematic review, which can provide this service. Additionally, because the process of a systematic review is organised, it guarantees that the synthesis will be both complete and unbiased, which is why it is the strategy that should be used for this research venture (Xiao and Watson, 2019).

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1.5. Aim and Objectives of the Research

1.5.1. Overall Aim:

The principal aim of this research is to comprehensively synthesise and evaluate existing qualitative studies that explore the perceived effects of air pollution on the respiratory health of adults aged 40-60 in urban areas of the UK.

1.5.2. Specific Objectives:

•    To analyse the effects of air pollution on middle aged people (40 years) of UK.
•    To analyse the effects of air pollution on elderly people (60 years) of UK.
•    To analyse the prevalence of health impacts of air pollution on elderly and middle- aged people. 
•    To recommend strategies for the mitigation of the observed air pollution effects on people of 40-60 years of age. 

1.6. Signposting for the reader

To guide the reader through this systematic review, the subsequent chapters have been meticulously structured to offer a coherent and comprehensive exploration of the topic. Following this introduction, the methodology chapter delineates the search strategy, selection criteria, and the approach to data synthesis.

Thereafter, the findings chapter presents the collated narratives and themes extracted from the selected studies, offering a synthesis of the perceived impacts of air pollution on respiratory health among the target demographic. This is succeeded by the discussion chapter, which juxtaposes the findings with existing literature, elucidating implications and drawing conclusions.

The review culminates with the conclusion chapter, summarising the insights garnered and suggesting potential avenues for future research. Throughout this review, readers can anticipate a rigorous examination, interspersed with relevant citations, of the intricate relationship between air pollution and respiratory health in urban UK settings. 

Chapter 2- Literature review

2.1 Introduction

Air pollution has a pervasive and critical environmental issue which has a worldwide implication for public health especially in urban areas. The effect of air pollution on human health are multifaceted that effects various physiological systems are leading to a myriad of health conditions. Among the demographic groups vulnerable to these health implications adults within the age range of 40 to 60 years are of particular concern due to their potential age-related vulnerabilities.

In this context, United Kingdom is not immune to these challenges that are posed by air pollution within urban areas which face a complex interplay of factors that include traffic congestion along with industrial activity and residential density that contributes to elevated pollution level.

In this context understanding the perceived effect of the air pollution on respiratory health outcomes among adults with an average age of 40 to 60 years is of much significant.

This literature review seeks to contribute the existing knowledge by providing a comprehensive overview of the current state of research on the perceived effect of air pollution on thehealth outcome among adults aged 40 to 60 in urban areas in the UK First up by analysing the available literature this review will identify gaps in understanding and emphasising the importance of conducting a qualitative systematic review in this specific context.

The systematic review will aim to analyse and synthesise the qualitative research findings and evaluate in a structured and rigorous manner to shed light on the diverse ways through which individuals perceive the effect of air pollution on their respiratory health.

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2.2 Critical analysis of important concepts

2.2.1 Air pollution in the UK

According to Doiron et al. (2019), air pollution in the UK is a multifaceted environment challenge with complex historical roots and contemporary implications. The UK, like many other developed nations, has undergone significant transformations in its approach for mitigating air pollution.It is important to consider the historical context along with contemporary trains and key challenges for appreciating the current state of air quality in the UK especially in urban areas.

The struggle of the nation with air pollution is deeply rooted during the Industrial Revolution as in the 19th and early 20th century is rapid industrialization had led to severe air pollution in cities like London which is catered by the famous “pea-souper” which contain high levels of sulphate dioxide and particulate matter.

These smog have been responsible for several health problems and fatalities which was observed in case of The Great Smog of 1952 which led to the death of thousands and was a catalyst for early air quality regulations.According to Huang et al. (2021), the important concepts that are related to air pollution and respiratory health includes pollutants like particulate matter, nitrogen dioxide and volatile organic compounds.

These pollutants are released from various sources including vehicle emissions along with industrial processes and heating that contributes to compromised air quality in the urban areas. Inhalation of this pollutants can directly and indirectly affect respiratory health by exacerbating pre-existing conditions or leading to the development of new conditions among the population.

In the recent decades the UK has made substantial progress in reducing sub traditional air pollutants especially sulphate dioxide and particular matter which has been achieved through regulatory measures like the clean air act and the widespread transition of coal to cleaner energy sources.According to Barnes et al. (2019), several new challenges have emerged which includes elevated level of nitrogen dioxide that is predominantly emerging from road traffic and the complex issue of particular matter especially PM2.5.

Urban areas especially London have been struggling with the level of nitrogen dioxide that exceeded European Union air quality standards which necessitated further regulatory reactions and low emission zones. Air pollution is influenced by different factors which includes population density transportation system industrial activities and residential heating methods.

The traffic emission plays the major contributor with diesel vehicles and congested city centres often being focal point of the concern. Industrialprocesses while more regulated than in the past can still contribute to localised air quality issues. Therefore, these challenges of balancing economic growth and environmental protection remain a significant concern for the nation.

2.2.2 Respiratory health outcomes due to air pollution

The respiratory health outcomes are of significant importance as they have immense affect the well-being and quality of life of life of individuals especially in the context of air pollution. Adults in the 40-60 age group often faces a range of respiratory health issues due to air pollution.

According to Redondo-Bermúdez et al. (2023), COPD encompasses chronic bronchitis and emphysema which are characterized by persistent airflow limitation and respiratory symptoms. It is a common condition among older adults and is considered to be a leading cause of morbidity and mortality globally.

Asthma is a chronic respiratory condition which is characterized by inflammation of airway and bronchoconstriction that leads to symptoms such as wheezing, coughing and breathlessness(Parra et al. 2022). While asthma often initiates in childhood which can persist into the adulthood and develop later in the life.

Acute and chronic bronchitis are being characterized by the inflammation of the bronchial tubes that leads to mucus production and coughing. Chronic bronchitis is a common manifestation in older adults and could be exacerbated by air pollution.

Respiratory health conditions have a significant effect the quality of life for the affected individuals. According to Parra et al. (2022), this could lead to chronic symptoms, hospitalizations, exacerbations and increased healthcare utilizations. These conditions often require lifelong management which includes medication alleged lifestyle modification and severe cases oxygen therapy or surgical interventions.

The burden on health care system and society is substantial including the whole scenario of health outcome. In the United Kingdom these respiratory conditions represent a substantial healthcare burden especially chronic obstructive pulmonary disease in particular which is the leading cause of disability and mortality.

According to Wang et al. (2021), understanding the prevalence and impact of these respiratory health condition is important in the context of air pollution research as exposure to these pollutants can exert our symptoms increasing the risk of exacerbations and contributing to the disease progression.

Asthma affecting millions of people of all age and lung cancer is a significant concern with the UK having one of the highest rates in the Europe. Adults age at 40 to 60 are particularly vulnerable due to age related changes in lung function and increased susceptibility to in respiratory illness which makes the exploration of the perceived effect of air pollution on this respiratory health critical aspect of the public health research within the nation.

2.2.3 Impact of air pollution on respiratory health

The relationship between air pollution and respiratory health is well established with extensive research highlighting the detrimental effect of airborne pollutants on the respiratory system. According to Luo et al. (2022), air pollution especially in the form of fine particulate matter along with nitrogen dioxide and other pollutants could result in a wide range of acute as well as chronic respiratory health effects.

Short term exposure to elevated rivers of air pollution has been reported to be associated with acute respiratory outcomes which can be manifested as exacerbation of pre-existing respiratory conditions like asthma and COPD. Symptoms might include increased coughing along with wheezing shortness of breath and bronchial constriction which could lead to increase emergency department visits and hospital Admission for respiratory issues.

According to Gao et al. (2023), the elderly population which includes adults between the ages of forty to 60 is especially susceptible to the short-term effect due to their age-related vulnerabilities. On the contrary long-term exposures to air pollution has more insidious and chronic effect on respiratory health. Prolonged exposure to pollutants like particulate matter and nitrogen dioxide has been linked with the development of chronic reciprocity conditions.

Studies have shown that individuals living in areas with high levels of air pollution are at an increased risk of developing COPD. Furthermore, air pollution has been recognised as an important risk factor for lung cancer which contributes to the development of malignancies within the respiratory system. 

Adults in the age between 40 to 60 faces significant vulnerabilities regarding the effect of air pollution and respiratory health. According to Travaglio et al. (2021), age related changes which include lung function along with declining lung electricity and decreasing respiratory muscle strain makes them more susceptible to respiratory issues.

Moreover, individuals within this age range often experience longer exposure histories to environmental pollutants that can be regarded as a compound effect of air pollution on their respiratory health.

In this context in United Kingdom urban areas are particularly affected by air pollution due to factors like traffic emission along with industrial activities and residential heating which increases the health burden associated with air pollution. The UK government has taken various measures to medicate air pollution but challenges remain especially in meeting European Union air quality standards.

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2.2.4 Vulnerable factors that contributes to the condition

Understanding the vulnerable factors which affects adults aged between 40 to 60 in the context of air pollution and its effect on respiratory health is important in the present environmental condition. According to Gale et al. (2020), these factors encompass a wide range of individual along with demographic and environmental variables which makes this demographic especially susceptible to the effect of air pollution.

Adults in the age of the range between 40 to 60 years’ experience physiological changes in the respiratory system which makes them more vulnerable to the adverse effects of air pollution. Lung function naturally declines with age that is characterised by reduced lung respiratory reserve and a reduced ability to cope with environmental stressors which includes air pollutants as well.

According to Fenech et al. (2019), the presence of pre-existing health conditions could significantly excessive at vulnerability as many individuals within this age group might have a history of chronic respiratory health issues.These conditions could exacerbate by the factors including air pollution exposure that leads to more severe symptoms and increased health care utilisation.

According to researchers Wu et al. (2022), it has been observed that genders play a vital role in vulnerability with research suggesting that men and women may have different susceptibility index to the effect of air pollution. For example, some studies indicated that women might be more responsive to certain air pollutants which makes them experience more severe respiratory symptoms.

According to Wu et al. (2022), hormonal differences might contribute to variations in how men and women respond to environmental stresses. Socioeconomic status has been considered to be another critical determinant of vulnerability towards air pollution according to research lower income individuals might face barriers to access health care facilities like medication and treatment for respiratory conditions that could exacerbate the health effect of air pollution. Additionally, socio economic disparities could also lead to differences in leaving environments especially with lower income individuals who are more likely to reside in areas with poor air quality.

On the other hand, according to researchers Nemitz et al. (2020), the location of residence is also an important factor that contributes to the vulnerability of air pollution and its immense effect individuals living in urban areas with high levels of air pollution face increase exposure while those in the rural areas might benefit from the clean air surrounding their place. This proximity to pollution source like major roads or industrial facility has a major effect on the vulnerability for the urban living people.

However according to some researcher genetic viability is considered to be one of the major factors those effects the susceptibility of an individual towards air pollution.

According to Huang et al. (2021), some genetic factors might make some people more resilient to environmental pollutants while others may increase susceptibility. Research into genetic determinants of vulnerability is still ongoing and is a complex determinant according to some studies published in the recent years. In the context of United Kingdom this vulnerability factors takes a vital role on the unique dimensions due to the specific socioeconomic and healthcare context of the country.

Although there are several contradictions to these findings however research is still going on based on the genetic factor which contributes to the vulnerability and susceptibility of an individual towards effect of air pollution.

2.2.5 Perceived effects of Air Pollution

According to Barwise and Kumar (2020), for most of the population the daily struggle initiates with the pervasive presence of air pollutants exacerbating conditions like asthma along with bronchitis and allergies individuals often recount their breathlessness and persistent coughs which describes themas ever-present companions which affect their overall quality of life.

Their narratives highlight the distressing feeling of being constantly under some irritation due to particulate matter and nitrogen dioxide triggering acute symptoms and prompting frequent hospital visits. Emotional stress is substantial as these individuals’ express feelings of being frustrated which is accompanied by anxiety and helplessness as due to being unable to escape the urban environment where they live.

They describe how they cherished outdoor activities have been infrequent which was curtailed by concerns for their respiratory well-being. As time passes their personal experiences reveals a sense of resignation with some reluctantly adapting to a new normal of living with compromised lung infection.

These narratives while poignant also underscores the urgent requirement for more robust environmental policies as well as public health interventions for mitigating air pollution and fostering a cleaner and healthier future for urban residents in the UK and beyond.

2.3 Theoretical framework

The theoretical framework underpinning this research is deep rooted in the environmental health along with epidemiology and public health theories with the concepts related to air pollution and respiratory health understanding this framework is important for conceptualising the research on the perceived effects of air pollution on respiratory health outcome among adults age 840 to 60 years in urban areas of the UK.

Environmental health theory: this theory provides the over a King Foundation of the research study as it recognises the human health as inextricably linked to the quality of the environment in which individuals live.

According to Clahsen et al. (2019), in the context of air pollution this theory suggests that exposure to harmful pollutants can directly affect respiratory health as it emphasises the importance of understanding the complexity of environmental exposures along with pathways and individual susceptibilities in shaping the health outcome.

Epidemiological principles: these principles are integral part of this research study especially in assessing the association between air pollution and respiratory health. According to Hassan Bhat et al. (2021), epidemiology helps in quantifying the health dissociated with the environmental exposure thus highlighting the significance of the long-term exposure assessment along with those response relationship and the identification of susceptible population.

Public health theories: Concepts from public health theories like health belief model and the social ecological model are incorporated into this framework for this research work. According to Huang et al. (2020), The Health Belief model suggest that individual’s perception of the severity and susceptibility to a health threat along with the perceived benefits of taking action influence the health-related decisions and behaviour of individuals.

The social ecological model acknowledges the multi-level influence of the air pollution and health outcome including individual, interpersonal, community and societal factors. In this context it underscores that the perceived effect of air pollution on respiratory health of an individual are shaped by individual beliefs and broader societal and environmental context.

2.4 Literature gap

While extensive research has been explored with the quantitative aspect of air pollution and its impact on repeated health there are notable gaps in the existing literature especially concerning the qualitative dimension of this topic. Therefore, these gaps underscore the requirement for a systematic review focused on the perceived effect of air pollution on respiratory health among adults with an average age of between 40 to 60 years in urban areas of the UK. The Majority of existing research has predominantly adopted a quantitative approach focusing on epidemiological studies and health outcome measure through statistical analysis.

While this work has been instrumental in establishing the link between air pollution and respiratory health it often lacks the in depth and context provided by qualitative research.Understanding the approach of an individual to perceive air pollution effects on their respiratory health their coping strategies and their risk perception is important for developing targeted interventions and policies.

In addition to this the vulnerability of adults with an average age of 40 to 60 years towards the effect of air pollution has been recognised but remains relatively unexplored from a qualitative standpoint. Most qualitative studies on air pollution and health have concentrated on broader age group with less attention given to the unique experiences and perceptions of this specific demographic.

As individuals in this age range often face age related vulnerabilities and might be managing pre-existing respective conditions along with understanding depth perspectives is important. While qualitative studies have explored perception of air pollution affecting the respiratory health in various global context there is a major requirement for research that specifically addresses the UK.

The air quality challenges in the UK along with regulatory framework and urban democracy differ from other regions making it important for investigation about how individuals in the urban areas of the UK perceive and respond to air pollution effect on their respiratory health.

Therefore, by addressing these gaps in the literature the systematic review proposed in this study aims to provide a comprehensive overview of the qualitative research conducted in the urban areas of the UK especially focussing on adults with an average age of between 40 to 60 years. 

2.6 Chapter Summary

In the conclusion it can be said that the significance of this resource topic lies from its potential to provide valuable insight into the human experience and emotions that are associated with air pollution and respiratory health.

While extensive quantitative research has established a clear link between air pollution exposure and adverse respiratory health impact the qualitative dimension remains relatively unexplored individual’s perception of air pollution and its impact on their respiratory health can profoundly influence their behaviours along with attitudes and choice related to exposure reduction and healthcare seeking.

As such comprehending this perception is important for developing effective public awareness campaigns that are tailored by interventions and informed policies which addresses the concern of this age group. 

Chapter 3: Research Methodology

3.1 Introduction

Research methodology serves as the structured framework guiding the entire research process, encompassing the systematic collection, analysis, and interpretation of data (Sileyew, 2019). It is the foundation that ensures the reliability and validity of a study's findings. There are four types of research methodology, and these are quantitative research, mixed-method research methodology, qualitative research methodology, and experimental research methodology (Taherdoost, 2022).

This study will discuss which research design was selected and the reason for choosing this one. In this context, a systematic literature review has been chosen as the research method that is a sort of qualitative research. Beside setting the research design, this chapter would also provide an overview of the established inclusion and exclusion criteria, searching and screening strategies, data extraction methods, ethical considerations, and the data analysis approach. 

3.2 Research design:

In research the design is known as the plan to find the answers or fulfil the objectives. In simpler terms it could be stated that, a research design is the portion of the research methodology indicates about a specific set of guidelines as well as process that guide the course of the study, as per the statement of (Newman and Gough, 2020).

In this context of the research, the research design has been selected in systematic literature review. This research design has been known as a transparent one that helps the researchers to find and choose the most pertinent research articles and conduct an in-depth analysis of the available information from the research articles.

Secondary research designs are considered better when there is a lack of scope for primary research studies and the research has been performed by a single author.  The situation discussed in the above section shows that the current research study has also been performed by a single researcher only. Also, secondary research designs are associated with high evidence base (Mengist et al., 2020).

This increases the overall evidence base strength of the research findings. In other words, it can be said that the selection of secondary research design can be said to be justified. However, it has been observed that the selection of both cohort studies and cross-sectional studies for the systematic review was justified depending on the availability of primary research studies.

Moreover, a structure and rigorous approach is offered to the researchers by this research design that made this research to select this design as it would present a comprehensive understanding of the air pollution’ s perceived effect among the adults aged 40-60 and impact on their respiratory health, in the urban areas of the UK. 

3.3 Exclusion and inclusion criteria    

The following phase that was followed while conducting this research was developing the eligibility criteria to select research articles or literatures for this research. The parameters for the systematic review are established by the inclusion and exclusion criteria.

Usually, they are selected after the research issue is established and before the search is carried out. When doing research on a certain group of the population, inclusion and exclusion criteria are crucial.

They support researchers in continually, dependably, and unbiased identifying the study population (Garg, 2016). In this context the selected eligibility criteria are mentioned below:

Inclusion Criteria:

•  The first inclusion criterion is that the research articles which were included in this SLR were peer reviewed and published in any journal. The rationale of selecting only peer-reviewed articles was to maintain the highest standard of scholarly rigor and reliability. Peer review ensures that the research has undergone evaluation by experts in the field, enhancing the quality of selected studies (Kelly et al., 2014).

•  The following criterion for selecting selected literature is that the research article that were focused on the selected topic. It was ensured that included studies must specifically address the research question, ensuring a direct and relevant contribution to the understanding of how adults aged 40-60 in urban areas of the UK perceive the effects of air pollution on their respiratory health. This criterion ensures the alignment of selected studies with the research objectives.

• The following research criterion is that the research that was published within the last 10 years (2013- 2023) were considered only. The 10-year time frame has been chosen as it helps the researchers to find out most recently published research articles and incorporate updated information and insights. In science or healthcare-based research it is uttermost important to include updated information to provide the reader the true findings. 

• The following inclusion criterion that has been established in this context was the publication language of the research articles. This research aims to incorporate the research articles published in English language only, as this language is universally accepted and readers from any part of the world could easily read the original sources (Neimann Rasmussen et al.,2018). This criterion ensures a more effective analysis and synthesis of the qualitative information within the research context.

Exclusion Criteria:

• The research articles which are not peer reviewed or not published in any journal have been excluded from this SLR. The research papers with more citations in other research studies are peer reviewed research papers.
  
  This shows that those primary studies have been reviewed multiple times in other secondary research studies. In this way, the exclusion of non-peer reviewed articles will be ensured. The rationale is that the research focuses to preserve the integrity of the research and improve the quality which is often ensured by the researchers in a peer reviewed research.

• The following exclusion criterion is that the research articles that are not directly related to the research questions have been excluded. The research articles mainly focused on respiratory health concerns of urban population of 40-60 years in the UK region. 

•  A 10-year publication period was included and therefore every research article published before 2013 was selected and excluded. This is because of the fact that those papers were considered to be old or obsolete in nature. 

• Finally, every study that was not published in English, were excluded from the research. In other words, it can be said that, if those papers were included, then the readers would have been unable to interpret the research findings and link them with the objectives. 

3.4 Searching strategy:

According to research evidence, it has been observed that systematic reviews are generally associated with keyword-based search strategy (Taherdoost, 2022). This means that data for the SLR, is mainly collected by using a keyword-based search strategy.

The specific keywords utilised to collect data is selected directly based on the research topic. As the research topic was observed to be based on the effect of air pollution on the respiratory problems of older people in UK, therefore the keywords were selected according to that format only.

The databases were Medline, CINAHL and ETHOS (https://web.p.ebscohost.com/ehost/search/advanced?vid=0&sid=8eab1a25-b369-48ff-b3c2-e132e2fde527%40redis, https://web.p.ebscohost.com/ehost/search/advanced?vid=0&sid=020c4466-38b9-4541-9756-316a877e436f%40redis, https://ethos.bl.uk/).

A PEO framework was used for the selection of keywords. The PEO framework is generally used for qualitative secondary studies, where P stands for population, E stands for Exposure and O stands for the outcomes. Thus, the PEO based selection of keywords was placed in a table and has been reported below –

Table A – Keywords based on PEO framework

In the above table, it has been reported that specific BOOLEAN operators were used to frame the search strategy. The utilised BOOLEAN operators were OR for synonym separation and AND for the separation of different keywords. This type of keyword table representation has been observed in other systematic review-based research studies also (Whyle and Olivier, 2022).

Depending on all the available evidences and applicability of PEO in the current research study, the keyword table was developed accordingly. Furthermore, it has also been shown that BOOLEAN operators are generally used to refine the search framework as well as get the desired search results, with a large variation. Therefore, the use of BOOLEAN operators in the search process can be said to be justified. 

On a summarizing note, it can be said that increasing data variation in the search results has further decreased the chances of data generalisation in the outcomes of the research. Therefore, using keyword search strategy was beneficial for the current SLR based research study.

3.5 Screening strategy

PRISMA flowchart was utilised in order to represent the screening strategy, used in the data collection process of the current SLR based research. PRISMA flowchart-based representation of screening strategy has been used in other SLR based research studies also (Kelly et al., 2014).

The PRISMA flowchart or framework-based screening strategy is responsible for showing the comprehensive steps, followed to collect research papers for review purposes. Depending on the above evidence,

PRISMA framework was used to screen the collected data by using the above stated search strategy. The strategy involved the removal of duplicate papers, after looking at the titles of the research study. Nevertheless, a large number of papers got excluded in this step, still there were a large number of papers for further screening.

The process was followed by the abstract screening process, where the abstracts of the individual collected papers were thoroughly screened. In this step also, a specific number of research papers were excluded.

Moreover, this screening step was followed by another process known as the body of paper screening. In this step, each of the research papers were opened by accessing the pdf files, and the whole paper was screened to look for relevant content to support the current study. A significant number of papers were further excluded after the completion of body screening. Furthermore, the whole screening process was completed after 11 papers were found to be relevant for the current research.

Comprehensive reviews linked to this area will strengthen the review process and its robustness by reducing disputes. The systematic review process was transparent and reproducible because selection options and inclusion and exclusion rights were clearly recorded. The aim of this rigorous selection process is to provide a final study option that meets the highest standards of quality and relevance and serves as a basis for the literature review and subsequent stages.

PRISMA flowcharts are placed in the results chapter of most of the systematic reviews. Moreover, the PRISMA flowchart was represented in the results chapter of the current research study. 

3.6 Data extraction    

In a systematic literature review, the stage of data extraction is a vital component in which a standardized as well as systematic approach is applied with the focus to collect relevant information from the chosen research articles, which has been found from the study of (Büchteret al., 2020).

It was also seen that carefully crafted data extraction form has been developed for facilitating the methodical extraction of key details, which ensure comprehensiveness and consistency in the synthesis of findings. In this systematic literature review the data have been extracted in a tabular format in which the author details, year, study aims, study design, participant details, study findings all have been incorporated.

By incorporating this information this research provides the readers with the details of the research articles. For example, from the data extraction table the readers could know if the research articles are qualitative or quantitative. 

The data extraction table that was used in the current research study included the author names, study aim followed by the design of the research, (sample) country/setting related data, followed by its type of exposure with its description, that was in turn followed by the primary outcome measures and finally completed with the key findings.

The structure of the data extraction table, used for the collection of data has been represented below –

Table B: Data extraction table (Structure)

Author Names    Study aim    Study design    Sample    Exposure    Exposure description    Primary outcomes    Outcomes

By using the common data collection or extraction method in the above-mentioned table, the research makes sure that the data collected from each research article are uniform. Furthermore, this systematic approach of data extraction allowed the researchers to compare the data of the research studies that facilitated a coherent synthesis of qualitative evidence. Overall, the systematic execution of this data extraction phase leads to the overall reliability and robustness of this systematic literature review.

3.7 Ethical issues    

Ethics is still a crucial factor in reporting and interpreting results, even though it is not necessary for the study of the literature that has already been published (Donato and Donato, 2019). The study team understands that it is ethically required to treat the data from the initial trials with the highest discretion and respect. Protecting the rights and privacy of the individuals whose experiences are compiled in the systematic literature review is necessary to achieve this.

One of the most important ethical factors in reporting is transparency (David 2015). In order to provide readers with enough information to comprehend the context and complexities of the chosen research, the systematic literature review is bound to the criteria of accurate and straightforward reporting. Transparently outlining the method, the data extraction procedure, and any review limits are all part of this.

The study hopes that doing this will preserve the values of honesty and integrity in academic research.Moreover, ethical issues encompass the conscientious dissemination of results. The synthesishas been conducted with a commitment to avoiding sensationalism and ensuring that the results are presented in a manner that accurately reflects the nuances of the original studies.

This approach upholds the ethical responsibility to contribute to the dissemination of knowledge in a responsible and respectful manner. Furthermore, a variety of sources of information must be reviewed while performing a systematic literature review (SLR). It is critical to protect sensitive data's confidentiality and privacy (Donato and Donato, 2019).

The research was successfully completed within the allotted time frame since these guidelines were appropriately followed. Another significant element that may contribute to an inadequate portrayal of this literature is publication bias. Furthermore, to avoid plagiarism issue no content was directly copied or pasted which might cause academic misconduct. Moreover, the authors were given credits throughout the research from which the information for the SLR was taken. 

3.8 Data Analysis    

Data analysis approaches fall into two categories: quantitative and qualitative strategies. From the above, it can be seen that in this research the qualitative data analysis method has been selected. According to Snyder (2019), this indicates that the data examined for this study is descriptive al in nature. Furthermore, it can be said to analyse the data collected a thematic analysis approach has been followed.

Thematic analysis, a popular qualitative analysis method, was used as a selective method to uncover the complexity of the impact of air pollution on the respiratory health of adults aged 40–60 years in urban areas of the UK. According to an evidence piece, it has been observed that thematic analysis helps in directly addressing the research objectives in an easier way (Sileyew et al., 2019).

As thematic analysis was performed by open coding format in the current research, the themes were associated with providing direct answers to the research question. Moreover, it can be said that the themes generated for the research were based on the main concepts, obtained from all the evidence pieces.  

Thematic analysis has also been observed to have advantages, which made it effective to be used for the current research. The open and systematic use of thematic analysis improved the integrity and reliability of the research findings.

Apart from this advantage, it allowed the author to dive deeper into the findings section of each of the 11 research studies. In other words, it helped the author to avoid missing of any important data from getting considered for the present study. Thematic analysis has also been observed to be effective for analysing qualitative data (Teixeira et al., 2023).

As the current research study is based on performing research study based on qualitative data, questionnaire based information were primarily reviewed and analysed as per the research objectives. Therefore, it can be said that, depending on all the above evidences, the use of thematic analysis can be stated to be justified for the current SLR based research study. 

3.9 Summary

In order to effectively synthesize qualitative research on the perceived effects of air pollution on respiratory health among individuals in urban areas of the United Kingdom between the ages of 40 and 60, this study uses a systematic literature review (SLR) technique.

While the exclusion criteria weed out non-peer-reviewed literature and studies that do not directly tackle the research issue, the inclusion criteria ensure the selection of peer-reviewed research published during the previous 10 years and focused on the study subject.

The searching strategy utilizes electronic databases such as PubMed, CINAHL, and Google Scholar, employing a combination of keywords and Boolean operators for a thorough and precise search.

The two-step screening process involves initial assessment of titles and abstracts, followed by a detailed evaluation of full texts to confirm eligibility. Ethical considerations guided the responsible reporting and interpretation of findings, maintaining the confidentiality of participants in the original studies.

Key information such as author details, publication year, research design, participant characteristics, and perceived effects of air pollution on respiratory health have been systematically extracted with the help of a standardised data extraction form.

The methodology for data analysis used is thematic analysis, which begins with introducing oneself to the data and proceeds to the methodical creation of preliminary codes aimed at identifying key issues.

The iterative technique allows for dynamic and reactive alterations by continuously comparing original codes to form overarching themes. The implementation of theme analysis in a clear and methodical manner facilitates the development of a nuanced knowledge of the perceived impacts of air pollution on respiratory health within the target demographic.

In summary, this study's methodology demonstrates a precise and methodical approach to carrying out a qualitative systematic review. In order to thoroughly examine and collect the available qualitative data on the effects of air pollution on adults' respiratory health in urban areas in the United Kingdom, it integrates conventional methods including theme analysis, inclusion and exclusion criteria, and systematic literature evaluation.

The methodological decisions are in line with ethical guidelines, ensuring the validity, transparency, and applicability of the study's conclusions.    

Chapter 4 – Results

4.1. Introduction

The current chapter has been written by keeping focus on the representation of the study findings. The study findings have been represented mainly in the data synthesis section. However, before arriving at the finding representation, the PRISMA flowchart has shown the process of getting the relevant pieces of evidence for data analysis.

Furthermore, the papers were briefed in the data extraction table and analysed by thematic analysis in the later sections of this chapter. Finally, the chapter was closed with a summary section.  

4.2. PRISMA flowchart

The PRISMA flowchart representing the process of data collection has been presented below-



Fig 1: The PRSIMA flowchart showing that 11 papers were selected from the 300 research papers, observed as the results. The selection process has been represented in the whole PRISMA flowchart below.
Source: (PRISMA)

4.3. Data extraction

Table 1: The data extraction table, showing the data obtained from 11 research papers, selected for the current research study

4.4. Data synthesis

The research works presented in the above table have shown the effect of air pollution on the health and wellbeing of UK population. Each of the studies have been observed to address specific aspects initially ranging from both mortality rates due to air pollution and air pollution’s impact on road safety.

According to Doiron et al. (2019), it can be said that increased particulate matter in the air contributes to reduced lung functioning. This problem can also lead to an increasing prevalence of COPD in the UK population. 

Synthesising the second research, it can be said that Lelieveld et al. (2015) primarily focuses on analysing the level to which air pollution affects premature deaths of people.

Air pollution has been observed to increase the premature mortality rates by 3 times. The same was also observed to be associated with 3 fold increase in GP visits and hospital visits. The research study has shown the role of PM 2.5 and Nitrogen dioxide concentrations in increasing hospital visits. The mortality rates were predicted to be doubled by 2050. 

Synthesizing Ahad’s research from 2022, it was observed that air pollution and healthcare sector utilisations were correlated. The research study has shown similar findings to that of Lelieveld et al. (2015), which stated that increased exposure to air pollutants, further increases the hospital visits.

The study has also shown that PM 2.5 and NO2 concentrations had a strong relationship with increased hospital visits. However, it was observed that ethnic variations did not alter the effects of these pollutants on the UK population.

Furthermore, synthesizing the research work of Carey et al. (2013), it can be said that there is a relationship between long term exposure to the outdoor air pollution and increased mortality rates in the UK population.

The research paper has further shown that air pollutants such as Sulphur dioxide and Nitrogen dioxide, combined with carbon monoxide were mainly responsible for increasing mortality rates due to air pollution. However, this increase in mortality rates was mainly backed up by COPD and lung cancer. CVD prevalence play a co-morbid role in increasing the mortality rates. 

Sager (2019) has stated that air pollution decreases road safety in the UK streets. For example, the evidence has shown the impact of the Great London Smog 1952, which had huge impact on road safety and people. The research study has primarily shown that vehicles are the primary causes of air pollution. The study has further shown that elevated air pollution levels make it harder for drivers to see on roads.

This leads to increase in accidents and high mortality rates among the selected population. The study has shown a unique relationship between air pollution and traffic-based accident outcomes (Sager et al. 2019). 

Garcidueñas et al. (2014) has stated the impact of air pollution on individual brains in the UK. After using a cross-sectional research design, the study has revealed that ambient pollution can reach human brain. This reaching of human brain has been observed to finally result in the development of neurodegenerative disorders (Mengist et al. 2020). 

Lui et al. (2019) on the other hand has specifically employed a correlational research design in order to analyse the relationship between air pollution and daily mortality rates of UK cities. The research has again shown similar findings as the previous studies regarding the strong association between PM10 concentrations and higher mortality rates. The correlations have been observed to remain robust post adjustment of gaseous pollutants. 

Newbury et al. (2019) has investigated the relationship between psychotic experiences and air pollution exposures also. Therefore, it can be stated that air pollution also affects the mental health of human beings. Finally, it can be said that the narrative synthesis of the studies has revealed the effect of air pollution on the middle aged to elderly population of 40-60 years of age, living in UK. 

Adam et al. (2015), Travagilo et al. (2021) and Di et al. (2017) has also talked of the relationship between air pollution and lung infections. The research studies have stated that high air pollution levels, opens scope for increase in COVID 19 infections in the UK population. 

4.5. Thematic analysis

Theme 1: Effect of air pollution on respiratory health of middle aged and elderly people in UK, respectively (40-60 years)

The effects of air pollution on middle aged and elderly people were found to be harmful from the selected research papers. The research papers have collaboratively stated that people belonging to 40-60 years of age are suffering from severe health impacts due to air pollution. Carey et al. (2013) has stated that long term air pollution was associated with high mortality rates.

The findings from other papers such as Ahad and Liu, have individually reported the increase of SO2 and NO2 in UK air. These increases in particulate matters in air, further increases the risk of exposure of people to these air pollutants. Particulate matters from air, directly travel to human bloodstream via the respiratory tract. In this path, they not only destroy the lungs, but also lead to the deterioration of cardiovascular health also.Increasing air pollution levels lead to increasing chances of severe acute respiratory syndrome or SARS caused by COVID 19.

Air pollution has also been observed to result in decrease in road safety in UK (Sager, 2019). Thus, it can be said that the UK population is vulnerable to air pollution. On a summarizing note, the two main effects of air pollution on the 40-60 years population are – health effects and road safety reduction. However, the examples of several diseases caused by air pollution, in the UK population, have been given in the next theme. 

Theme 2: Prevalence of respiratory health disorders due to air pollution in middle aged and elderly people in UK

The research studies have shown that there is an increasing prevalence of respiratory disorders and CVD in the elderly individuals of UK. The middle-aged people are mostly affected by CVD and the elderly people were mostly been observed to be affected by severe respiratory disorders. COPD, asthma and lung functioning deterioration have been observed to be the highly prevalent respiratory health disorders. According to Doiron et al. (2019), there has been a major association between decreased lung functioning and ambient air pollution.

Higher prevalence of respiratory disorders was mostly observed when PM was above 2.5 or PM was 10. This is because of the fact that an increasing prevalence of COPD was observed in the elderly population, exposed to air pollution in UK. On the other hand, outdoor air pollution also increased the risks of stroke, depression and visual disturbances in the UK population (Carey et al., 2013).

Another highly prevalent air pollution associated respiratory health effect as shown by Adam et al. (2015) was lung infections. This is because of the fact that air pollutants comprise of harmful compounds, which can cause genetic mutations, leading to cancer. Although respiratory health disorders were mostly observed to be associated with the people, neurological disorder prevalence was also evidenced.

Some risks of Parkinson’s disease and Alzheimer’s disease due to air pollutants breaching the blood brain barrier were also observed in the study results (Garcidueñas et al., 2014). However, it can be said that most of the effects were based on respiratory health of the selected population. Therefore, it can be said that the prevalence of respiratory disorders is significantly high in the UK middle to elderly population, considering air pollution as the cause. 

Theme 3: Recommendations for the reduction of air pollution in UK

After going through all the above evidenced research studies, it can be said that there is an evidence of increasing disease risks due to air pollution. Mitigating the disease risks will further reduce the burdens on healthcare sectors. The target of the recommendations will be to reduce the hospital visits of UK middle aged and elderly people (Ahad et al., 2022).

A reduction of PM2.5 based on reduction in levels of NO2, SO2 and CO needs to be ensured. In order to assure this, reduction in the burning of fossil fuels is necessary (Di et al., 2017). The importance of policies for the usage of cleaner energy sources is also imminent.

Increasing the public awareness and usage of campaigns to educate individuals in eco-friendly practices will further help in reducing air pollution (Adam et al., 2015). The planning of cities in UK should mainly be focussed in the development of green spaces, which can counter air pollution. 

On a summarizing note, it can be said that the above synthesis of themes have shown that there is a crucial need for targeting the middle aged and elderly population, concerning the reduction of air pollution in UK. This section of the population has been observed too suffer the most from the diseases. Therefore, addressing the health impacts on these people is justified for the future research studies also. 

4.6. Summary

Chapter 4 was mainly focussed on comprehensive analysis of the research results. A structured approach was used to represent the data as well as its synthesis. The results of study were obtained by synthesizing data from the extraction table. Theme based representations were made under the thematic analysis section of this chapter which was comprised on the common concepts of discussion, present in all the studies.

The chapter has addressed the study aim and objectives, and by now, the effect of air pollution on human beings is clarified. There is an urgent need to reduce the level of air pollution in UK, to reduce mortality rate and ensure a better quality life to the 40-60 years aged population.  

Chapter 5 – Discussion

5.1 Introduction

A comprehensive discussion of the results will be provided in this chapter. Analysing the wide variety of research papers that evaluated how air pollution could impact the respiratory health of individuals in urban areas between the ages of 40 and 60 years would be the primary emphasis.The next debate not only deconstructs the foundation of these findings but also connects them with important discoveries gleaned from a larger body of literature.

Combining these many points of view results in a thorough grasp of the problems and possible solutions, offering a strong foundation for further activities and efforts related to this complicated topic. For that reason, this chapter would discuss about the strengths and limitations of this research, future implications of the findings of this research and describing the recommendations to improve the focused problem and the scopes or opportunities of research. 

5.2 Critical discussion on findings:

After evaluating the research studies included in the findings sectionit was evident that the research articles incorporated in this context consistently pointed out that air pollution negatively affects respiratory health and lung function among the adult population (within the range of 40 and 60 years) in the urban areas of the UK.

From the included research studies there is a strong connection found betweenambient air pollution and development ofvarious respiratory diseasesbecause ofreduced lung function particularly development oflung cancer and chronic obstructive pulmonary disease (COPD) (Doiron et al. 2019).

The included research studies in the finding section highlighted the immediate requirement address particulate matter in the air, especiallyPM2.5, which is associated majorly with development of respiratory problems among the targeted population. The analysis of this data suggests that to lower air pollution levels and minimizes the health hazards that go along with them, specific initiatives are urgently needed.  

This finding was supported by the research done by Xing et al. (2016) in which it was found that oxidative stress along with PM2.5-induced cytokine release are the primary processes linked to respiratory disease development such as COPD. Therefore, it can be stated that the middle to elderly aged people had to breathe heavily to inhale enough oxygen to support their respiration.

As observed in another research study, extremely high levels of air pollution led to respiratory disorders such as abnormal breathing rates and breathing problems (Vohra et al. 2021). Unbelievably, the particles in PM 2.5 may directly induce mononuclear inflammation or upset the microbe balance, which would aid in the onset and aggravation of COPD.

The incidence of lung infection due to air pollution has been reported in another research study (Horton et al. 2023). Therefore, it can be said that the findings concerning lung infections caused by air pollution is also justified for the current study.

Moreover, previous research studies have discussed the mechanism by which PMs from polluted air, enter the human body as discussed in some of the research papers for the current study. In other words it can be said that the current research study has provided mechanisms of crossing the blood brain barrier also, after the PMs enter the body via respiratory tract. 

On the other hand, the research articles included in the finding section collectively about the severe consequences of outdoor air pollution especially PM 2.5 and its association on overall outcomes of the health and premature mortality.

The research of Lelieveld et al. (2015)pointed in their research that PM 2.5 is a major contributor in the elevation of early deaths throughout the world. This statement is supported by the research of Xing et al. (2016) in which the researchers added that PM 2.5 could be major risk factor and the particles alongside other particles <2.5 mm in diameter can penetrate the lungs, the result in corrosion and irritation in the wall of the alveoli.

This condition subsequently deteriorates the function of the human lungs. The research also stated that the effects of PM 2.5all the respiratory system need to be addressedimmediately which they found from the epidemiological, mechanism and experimental studies. They added that by mitigating the adverse impact of PM 2.5 the respiratory health of the individual in the urban areas could be improved.

CVD as a complication of respiratory health disorders have also been reported in another research study (Garg, 2016). Evidences for stroke and CVD have also been observed in the findings of the current research study. Therefore, it can be concluded that respiratory disorders become complicated and progresses to cardiovascular disorders also. 

On the other hand, the research included in the findings conducted byCarey et al. (2013)indicated a strong connection in between exposure ofoutdoor air pollution for a long time the UK region as well as increases in the mortality rates due to the development of respiratory diseases. In this context, the research conducted by Guo et al. (2023) supported the findings of this research and further added that PM2.5, PM10, and PM1 could be harmful as it might increase the risk of development of respiratory diseases and cardiovascular disorders which automatically elevates the rate of morbidity and mortality.

Evidences of lung cancer have also been observed to be associated with the current research (Fenech et al., 2019). A previously conducted research has reported that air pollution and constant exposure to the same are responsible for causing lung cancer. Another research evidence has shown that lung cancer is mainly caused when air pollution levels are measured at PM10 (Gale et al. 2019).

Moreover, another research evidences have shown that cells associated with cancer are mainly based on mutations. These mutation rates are increased due to the inhalation of particulate matters from air (Xing et al., 2016).

The research works have also demonstrated that air pollution wakes up the cells with cancer causing mutations and leads to accumulation of those cells, ultimately forming tumours (Jonidi Jafari et al.,  2021). In other words, it can be said that the current research study has provided evidences of the same and therefore, it can be said that the perceived health effects of air pollution as lung cancer is justified.

They added due to air pollution the particulate such as PM 2.5 not just the only contributor, but PM 10 could also result in lung disorders development if people are at long term exposure of these particulates. Hence this research highlighted to address air pollution issue and reduce the quantity of PM 2 and PM10 in the air to prevent cardiovascular diseases and respiratory problems.

Therefore, it can be said that evidences of increased prevalence of lung cancer, is also associated with existing knowledge base (Ahad, 2022). Overall, these researchstudies interpreted and highlighted a crucial need4 implementation of public health initiatives that target to reduce the air pollution and preventing the respiratory diseases to mitigate the increasing mortality ratesalongside improving the overall health outcomes of the individuals in between 40 to 60 years.

The evaluated research in the findings section further provides significant insights into the relationship between elevated healthcare usage, such as hospital admissions and GP visits, and air pollution. According to another previously available research evidence, it can be said that there is an increase in air pollution level in the urban areas (Pimpin et al. 2018). The results from another research study have stated that air pollution leads to increase in respiratory disorders as the causes of hospital admissions (Higham et al. 2021).

In other words, it can be said that GP visits are increased due to air pollution only. This finding of the current research can be stated to be justified for the current research. Ahad (2022)’s study clarifies the spatiotemporal relationship between air pollution and increased healthcare requirements, drawing on data from the UK Household Longitudinal Study.

The association that has been shown between the use of healthcare services and elevated levels of air pollution, namely PM2.5 and rising NO2 concentrations, highlights the complex health effects of air pollution. Increasing NO2 concentrations in air, can lead to the blockage of alveoli, that makes the process of breathing harder. According to this perspective, persons between the ages of 40 and 60 who live in air polluted metropolitan areas have greater medical demands, which call for the creation of tailored healthcare policies and treatments.

Furthermore, the results also concluded that air pollution is associated with risks to respiratory health and driving safety and mental ability. According to Sager (2019), there is a direct relationship between high air pollution and low road safety in the UK.

In addition, Garciduensince et al. (2014) focus on the impact of air pollution on cognition, as it enters the brain causing depression, stroke and neurodegenerative diseases, which was supported by the research of Costa et al. (2020). This perspective highlights the wider effects of air pollution on public health and calls for a comprehensive strategy to reduce the hazards to respiratory and cognitive health.

In this research context the systematic literature review design was followed to find out the perceived effect of air pollution on overall respiratory health of adult populationin the UK. This research adopted a well stabilisedas well as transparent research design that ensured the comprehensive examination of the relevant research studies that increases the credibility and reliability of the research.

Furthermore, the screening as well as data extraction of the research articles were done carefully and in a systematic way that automatically enhance the reliability of this research. Moreover, the research done in the context is successful 2 discuss the themes associated with the research topic and emphasisedabout the mechanism of air pollution in the development and degradation of respiratory diseases, the other diseases causedbeside lung disorder due to air pollution and the main contributor of this problem that is another major strength of this research.

5.3. Limitations

Despite following comprehensive and systematic approach, this research holdsnumber of limitations. It was seen that this research relied on systematic literature review as the study design that might notpresent the actual problem that the population in between 40 to 60 years in the UK region is currently experiencing due to the air pollution issues in the urban area.

This might hamper the reliability of the research which is not the case in the primary research design. The following limitation of the studies thatthis research was mainly focused on a specific population set which is 40-60 years and mainly resides in the urban area of the nation.

Selecting this population group and specific regionhey this research might have overlooked the other people in between 40 to 60 years in rural area where air pollution is also increasing day by day (Guo et al. 2023). Data generalisation can also be observed to be associated with the study findings. On the other hand, selection bias is also associated with the current research methodology.

However, other association health issues were also addressed apart from respiratory disorders. Moreover, in the context of urban areathe research could have incorporated the group of children and old demographics simultaneously as both the population group are at high risk to develop respiratory problems due to exposure of air pollution.

Furthermore, this research mainly focused on collecting and analysing the qualitative data by using thematic analysis method that could be a major limitation in terms of generalizability.   Since qualitative data interpretation is subjective, the themes that have been found may not adequately represent the range of experiences or take into consideration geographical differences in the perception of the consequences of air pollution on respiratory health.

The research study could have included quantitative analyses also, in order to address the level to which air pollution affects the respiratory health of people. In other words, it can be said that thematic analysis has only addressed the specific objectives of this research.

No novel findings were produced from the research study. To improve the accuracy and relevance of the results, future studies should think about reducing these restrictions by using a wider range of sources, taking linguistic factors into account, and extending the time frame.

5.4. Recommendations

The first recommendation that could be made in this context is specific to the research issue. The recommendation is focused on improving the respiratory health UK population bymitigating the effects of air pollution.

The government should promote and implement a stringent air qualityregulation that will promote the usage of sustainable transportation systems such as using electric vehicles, reducing the smoke emissions from the factories by using air filters.

The costs of implementing the recommendations for air pollution control should be compensated by the government along with increasing the public awareness campaign to know them about benefits of using sustainability practice (Jonidi Jafariet al.,2021), that will be helpful in reducing air pollution. 

The following recommendation that could be made in this context isfocused onimproving the methodological approach.Future research studies could adopt a more inclusive approach by minimising the publication bias. Moreover, the future research could carry outa mixed method research approach that combined qualitative and quantitative research which would enhance the generalizability the research findings (Schoonenboom and Johnson, 2017).

In addition, social inclusion and the diversity of diverse participants should be key to better understanding regional differences. Policy makers need to take these complex perspectives into account when developing respiratory health interventions in cities. Finally, fostering multidisciplinary cooperation between environmental researchers, health professionals, and legislators can address the complex problems posed by air pollution more effectively and efficiently.

5.5. Opportunities for future research

This present researchestablishes afoundation for several opportunitiesor scopes future research in the field ofair pollution and respiratory health.The first opportunity for future research is that future research studies could take up longitudinal researchdesign to get a detailed insight about this topic.

Moreover, this research design would allow the researchers to get the understanding the point of view of the people end giving the research the information about the adaptation policies strategies that people follow to deal with this air pollution and prevent respiratory problems (Gao et al., 2023). Further research into the socio-economic and cultural elements affecting perceptions can also provide insightful information that helps shape the creation of focused treatments. 

In addition, future research studies could use technological perspectives such as wearable air quality monitors to collectreal time dataand enhancetheaccuracy of estimation done onperceived health effect (Vohra et al., 2021).

In addition, future search studies have an opportunity to collaborate with environmental researchers, sociologist, epidemiologiststhat might help research include comprehensive details about the complex link between lung diseases, common social problems and detailed morbidity details due toair pollution.

This understanding can then be used to influence evidence-based policies and treatments. Secondary quantitative research designs can be observed as the opportunities for future research on this topic. 

5.6. Additional implications

The first implication of this researchcould be made in the field of public health. The findings of this research could be usedin developing targeted health intervention to addressthe lung diseases among thepeople of 40 to 60 years in the urban areas.

Based on the research findings and insightspolicy makers can createtailoredhealth services design, develop awareness campaign, andstrategies of urban planning that might overall improve the public health outcomeby minimisingthe impact ofair pollution in respiratorydisease cases (Sager, 2019).

Moreover, the concerns and experiences shared in this research might be very helpful to recognise and address the impact of air pollution on mental health of the targeted population and drive policymakers, healthcare professionals to make strategies for improving psychological wellbeing of overall population by addressing air pollution.

In addition, the findings of this study might be helpful for the government officials and policy makers to rethink about the environmental policiespresently functioning in the UK region (Berghs et al., 2016).

Based on theresearch findings and recommendationsthe policy makers could create extra environmental policy that would drivepeople to adopt sustainable behaviour such as using sustainable transportation methods, creating green spaces, and decreasingcarbon emissions that would contribute to the development of healthier living environmentalongside potential reduction of the burdens that caused by respiratory disease. Therefore, it can be said that the current research study has provided additional implications for UK, in making their way to neutralise air pollution in their countries. 

5.7. Summary

Overall, this discussion sectionsuccessfully explored the relevant literaturesthat supported and extended the research information found from the finding section. The discussion also agrees that there is a strong link in between air pollution especially PM 2.5 in the air and its contribution in the rapid development of adverse respiratory problems.

This discussion also highlighted the need for targeted intervention to address this issue on immediate basis. The recommendations section of thischaptersuggested using sustainable practices and making the environmental policy stricter. Future implications of the research emphasise the need for specialised health treatments, modifications to urban design, and ongoing efforts to improve air quality in order to improve public health outcomes.

Chapter 6: Conclusion

6.1. Synopsis of main findings

The main findings were focussed on the perceived effects of air pollution on the respiratory health outcomes of 40-60 years old people. The data synthesis and analysis section has produced findings, which were associated directly with the objectives of the research.

In other words, it can be said that the synthesis of data has revealed that the perceived effects of air pollution were mainly associated with respiratory health outcomes based on diseases and road accidents, being a health concern too. Moreover the perceived effects were also observed to include respiratory disorders and increased risk for CVDs, associated with respiratory disorders.  

However, it was also found that COPD, lung cancer, asthma, breathlessness, breathing disorders and deterioration of complete lung function were the perceived effects of air pollution in 40 to 60 years people. Therefore, it can be said that air pollution had both respiratory health as well as brain health effects on 40 to 60 years old people.

The thematic analysis has shown that there is a primary need for addressing air pollution that is mainly in consideration of elderly population as well as middle aged population. The research papers have revealed that the existence of PM2.5 in air was the main reason of the ill health effects, experienced by the selected population.

The first perceived effect observed for air pollution was lung function deterioration. Lung based disorders were mostly observed to have affected the respiratory health of 40-60 years old people, affected by air pollution. This deterioration has been observed to be associated with COPD that underscores respiratory implications based on exposure to air pollutants. COPD has been found to be a serious complication of the lung disorders, associated with high mortality rates.

The second perceived effect observed for air pollution on 40 – 60 years old people was CVD. Most of the research’s papers have shown that, the presence of NO2, SO2 and CO were responsible in increasing the prevalence of CVD in 40 – 60 years old population. Moreover, it was observed that PM10 led to CVD associated mortalities due to air pollution.

However, it has been observed that this CVD was prevalent as a complication of respiratory disorders among the pollution exposed group. In other words, it can be said that till now, the perceived effects of air pollution included respiratory and CVD associated problems for the human health. As cardiovascular health is based on circulation that is in turn connected with respiration it can be said that they affect the respiratory health of individuals also.

CVD associated with COPD have been observed to give rise to severe destruction of respiratory system in human beings. However, the other perceived health effects were observed to include neurological problems due to air pollution. In other words, it can be stated that apart from respiratory health problems, some other health disorders have been observed to be associated with UK people due to air pollution. 

However, apart from the respiratory health disorders, some other health effects of air pollution were also observed. The research study has dived deeper into the effects of air pollution on nervous system of human beings.

On the other hand, it was also observed that Parkinson’s disease and Alzheimer’s disease risks were also heightened by air pollution in the selected population. Higher levels of air pollution also led to increase in the prevalence of depression and anxiety, due to the existence of other health disorders.

These perceived respiratory health effects were directly associated with diseases caused in the population. However, it was also observed that air pollution led to the development of smog. This development of smog decreased the vision of car drivers of more than 56 years of age. The condition leads to an increasing prevalence of road accidents, which is directly associated with the highest causes of mortality rates in most of the nations. 

Therefore, depending on all the above evidence pieces, it can be said that air pollution has a detrimental effect on the respiratory health, followed by the overall heath among the population of 40-60 years old people. Based on all the evidence based outcomes and their critical justification in relevance to previously available evidences, it can be said that recommendations should be made to neutralise the perceived effects.

The recommendations will be targeted to reduce the levels of PM in air that will in turn decrease the overall prevalence of respiratory disorders among the whole population of UK. Finally, it can be stated that the research findings have well addressed the aim and objectives of the current study. 

6.2. Self reflection (awareness of knowledge and skills)

As a result of the completion of the research study, as the author, I have learnt about the current condition of Air pollution in UK. Furthermore, I have learnt to use keywords to search for research evidences, that can be used to perform a systematic literature review. I am also aware of the fact that air pollution still needs to be reduced in UK, to save the people from respiratory health disorders. Finally, I can say that the dissertation completion has increased by awareness in public health research in UK. 

6.3. Public health Implications of the research

The research findings have a major implication in the category of public health (PH). The evidences imply that air pollution imposes a huge burden on PH. Although the selected population was comprised of 40-60 years old people, air pollution has similar effects in all sections of the human population. Air pollution has been observed to be associated with a wide spectrum of health disorders that include complex respiratory diseases such as COPD, respiratory health disorders well as neurological conditions. Moreover, it was observed that heightened levels of mortality as well as hospital visits indicated by the studies have posed severe impacts on the human population.

Thus, policies should be developed to address the increasing level of air pollution in UK (Huang et al., 2020). There is thus the requirement of policies and programmes launched by the government and local bodies to reduce air pollution in the urban areas. These strategies will further help in neutralizing the observed health challenges. Health policies should also be made accessible to everyone in UK, so that they can avail those services for the treatment of their respiratory disorders (Parra et al., 2022).
In other words, it can be said that the government of UK should take necessary steps to reduce air pollution in UK. 

The research findings have also implied some recommendations for urban planning as well as policies to save the environment. The presence of strong association between reduced road safety and air pollution prevalence as stated by the findings creates a necessity to analyse all the urban areas and their levels of air pollution. In other words, it can be said that green spaces, promotion of electric cars and reducing the burning of fossil fuels will help in decreasing the prevalence of air pollution in the countries. The recommendations will be helpful in reducing the prevalence of air pollution. Governmental bodies and policy makers will be needed to use these strategies to protect both the human health as well as develop a more sustainable environment. 

The findings of the current study has talked of several equity and social implications based on vulnerable demographic groups. The research findings also imply towards the consideration of environmental justice. In other words, it can be stated that if cleaner air is made available in all nations, the harmful health effects of air pollution will no longer exist.

Therefore, the policies and awareness campaigns should be targeted towards making the air cleaner, in order to reduce the burden of respiratory disorders among the middle aged to older adults in UK. In other words, it can be stated that public awareness should also be increased about air pollution.

Although the research study has been performed in middle aged adults and elderly people, the implications are for the future of human community in every nation. The research study also implies that if the existing level of air pollution is not controlled, mortality rates among the 40-60 years old people will increase as they age.
Therefore, the population of UK must be more made more aware regarding the levels of air pollution in UK. These processes will help in protecting their health and will also ensure that they lead a high quality life in future. 

On a summarizing note, it can be said that air pollution effects on the health of middle aged and elderly people are multi-faceted in nature. However, it needs to be neutralized and well addressed in order to increase health quality of human beings.

The implications are mainly for the human population only, for every section of the society. These implications can also be utilized by the government and local bodies to develop policies and recommendations to tackle increasing air pollution. Future research works must be conducted after neutralizing the existing limitations of the current research study and considering the implications of the current research.

Top Healthcare Samples

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Appendices

Appendix 1: Data extraction table