Urban Pollution and TRAP’s Health Effects

Chapter 1: Introduction

1.1. Background

Traffic-related air pollution, also known as TRAP, can be defined as a category of air pollution resulting from the harmful emissions of the vehicles (National Institute of Environmental Health Sciences, 2019). In the urban sector, TRAP is one of the significant sources of pollution. In this regard, it can be highlighted that in the period of globalization, air pollution is impacting the environment and health of human beings that has been a significant concern. In a recent study, it has been stated that emissions from vehicles, pollutants in the atmosphere, road dust, and tire wear together forms TRAP. Human exposure to these mixture results in different health effects ranging from congenital disabilities to dementia (Matz et al., 2019). A study conducted by Health Effects Institute in the year 2010 identified that different health effects of TRAP include asthma, cardiovascular mortality, lung infection, atherosclerosis, and myocardial infarction, among others (Matz et al., 2019). Other harmful effects of human exposure to TRAP include eye irritation, skin problem, and chronic diseases such as cancer. The other sources adding to TRAP are, for instance, the emission of harmful gases from the industrial sites. Besides, the other human activities causing air pollution are the burning of woods and fossil fuel combustion that increases air pollution. Furthermore, the natural sources contribute to air pollution in the urban areas, such as a fire in forests, dust storms, and volcanic eruptions, among others (Francova et al., 2017. According to the report of the World Health Organization (2005), in modern life transport plays the most vital role. The economic development of a nation is also ensured by developing better contact through transport mode. However, these positive factors are all linked with human health issues caused by transport. The present situation of increased transport volume increases the threat to health due to the low quality. In this context, it can be stated that the quality of life of living people is dependent on the quality of the air environment. According to the statistics of the World Health Organization (2020), the world has 7 million deaths every year due to air pollution, out of which approximately 4.2 million deaths are due to (outdoor) air pollution. The data also reflects that 9 out of 10 in the low and middle-income economies are breathing in the air that exceeds the actual limit of pollutant-free air. Therefore, it becomes vital to take the initiatives and necessary steps to reduce the effects of TRAP and improve the quality of air (World Health Organization, 2020).

1.2. Research Aim and Objectives

The prime aim of this study is to conduct a systematic review to understand the impacts on the health of human being exposed to traffic-related air pollution.

The following are the objectives of the study based on the aim.

To identify the reasons behind traffic-related air pollution

To suggest suitable recommendations for mitigating the issue of traffic-related air pollution for improving the air quality and providing the scope to improve the health of individuals globally

1.3. Research Questions

Based on the aim and objectives, the following questions have been designed for the study.

R1. What is traffic-related air pollution?

R2. What are the factors causing traffic-related air pollution?

R3. What are the different health impacts of traffic-related air pollution on human beings?

R4. What are the recommended suggestions for improving the quality of air and mitigating the issue of traffic-related air pollution?

1.4. Brief Methodology

The research design followed in this study is the systematic review of the secondary sources of information. Additionally, a systematic review in this study has helped in gathering valid as well as reliable data for achieving the research aim and objectives. In this study, relevant articles were selected from Google Scholar to maintain the authenticity of the information provided. Besides, under the inclusion/exclusion criteria, the articles published between 2015 to a recent year were used and exclusively focused on the health impacts of traffic-related air pollution. For data analysis, tools such as MS Word and MS Excel were used to keep track of information gathered that can be used by the researchers to analyse these findings.

1.5. Rationale for this Research

In the recent period, research conducted has highlighted the impact of outdoor pollution on human beings' health. In this regard, most of the evidence has supported that air pollution from transport is the major contributor to pollution. In this regard, this particular study offers a systematic review of the existing literature associated with the TRAP and health hazards linked with such corruption. This study enables gaining an in-depth understanding of air pollution mostly related to transport in urban areas and the risk to human beings' health. Furthermore, research in this area helps identify the pattern of activities that increase the intensity of transport emission.

Chapter 2: Literature Review

2.1. Causes of Traffic-Related Air Pollution

According to the views of Suh & Zanobetti(2010), traffic congestion tends to escalate vehicle emissions while, on the other hand, it is found to degrade ambient air quality. According to the present studies, it has been noted that enormous morbidity and death take place for the drivers, individuals, and commuters who live near roadways. In most areas, vehicle emission has proved to be one of the primary sources of air pollutants that comprise carbon monoxide, volatile organic compounds, nitrogen oxides, and particulate matter. The rising severity, along with the period of traffic congestion, tends to possess the scope to raise the pollutant emission and also degrade the overall quality of the air. It becomes essential to divide all types of traffic-related pollutant impacts, along with risks, into two main parts. The first type of effect is congestion-free impacts, which imply traffic over volumes that lead to significant congestion. In such cases, the added vehicle in the road doesn't change traffic patterns. It can be explained by Greenwood et al. that the speed, along with travel time of some other cars, does not tend to be impacted. Furthermore, the vehicle emission factors are not at all, dependent on the traffic volumes. Hence, the additional vehicle's marginal impact tends to be in equilibrium with the vehicle fleet's average impact. However, this doesn't prove to be right in congestion, which is the second category. It has been identified by Warburton & Et. Al. (2010) that congestion can be identified as duration when the traffic volumes are higher than road capacity. Recurring congestion can be identified as congestion in high traffic volumes in weekday peak hour periods. In the case of congestion-related impacts, there are multiple interactions taking place with congestion. Here it is noted that congestion tends to minimize the average speed, thereby increasing the travel time and exposure over a per vehicle basis. It is also said that the congestion tends to reduce the scattering of vehicle-related pollutants because vehicle induced turbulence tends to be dependent on the speed of a particular vehicle. When the vehicle's speed is low, it is likely to raise the pollutant concentrations basically from roadway sources. It can further be noted that there is an alteration in the driving patterns because of congestion that leads to a rise in several speedups, stops, and starts, which raises the level of emission in comparison to the cruise conditions. It can be revealed that it is quite essential to segregate the congestion-free and congestion-related impacts because emissions, risks, and effects tend to vary, and such types of analyses can inform decisions that have been associated with traffic and air quality management along with impact and risk analysis. As per the views of Gaffney & Et. Al. (2016) it is quite significant to assess the value of air pollution impacts and health risks to the population living on and near roads taking place because of the recurring congestions during Monday to Friday rush hour traffic. It is frequent congestion that can lead to repeated and chronic exposures and a rise in the long term risks over the health. Incident congestion, which occurs because of an accident or disabled vehicles such as one that takes place by an accident or disabled car, has not been discussed in this study. However, such events also prove significant for acute health-related outcomes, such as asthma exacerbation.

2.2. Impact of traffic-related air pollution on human health

Moher & Et. Al. (2019) states the fact that air pollution has always been linked with different health issues that comprise of worsening of heart conditions and vast risks of asthma, stroke, heart attacks, and premature mortality. WHO recognizes the fact that ambient air pollution leads to 6.7% of all deaths. It is Particulate Matter that can be considered as one of the central air pollutions that tends to be linked with adverse health effects. Gaseous pollutants have also been associated with adverse health outcomes. Although ambient air pollutant concentration is declining entirely, pregnant women, children and the elderly, and the ones living with chronic medical conditions or the person with weak immune systems tends to be vulnerable to air pollution exposure, and there is a need for special precautions. In-person with coronary artery disease, air pollution has been linked with complications such as premature mortality and a rise in cardiovascular disease-related hospitalization and premature mortality. Several methods have been linked with increased risks, such as alteration in the blood viscosity, vascular dysfunction, altered autonomic function, and inflammation. As revealed by Kwon & Et. Al. (2017) it has been mentioned that routine exercise, as well as physical activity involvement, can be considered as significant for secondary prevention of CAD. Nonetheless, it is not clear when the advantages of physical activity tend to outweigh the short-term risks that have been linked with exercising in a polluted place. When the adverse long term health effects of air pollution have been developed, it is not known if the people living with CAD tends to suffer more from short term adverse cardiovascular events in comparison to the general population. The most well-known fact has been that the patients who live with CAD tend to live with hypertension also. It is a beta-blocker medication. It is found to moderate the interaction taking place between short-term exposure to air pollution and cardiovascular function. Lipsett & Et. Al. (2015) reveals the fact that technological enhancements and stricter emission standards would minimize vehicle-specific emissions. However, it is to be stated that distinct factors such as growth in transport, rise in the number of diesel cars, increasing short trips and traffic congestion would counterbalance the advantages that are derived from such enhancements. In the coming decade, other vehicle technologies might not make significant inroads to the market or might possess any impact on air quality. Some other factors might contribute towards preventing the minimization of people's introduction to transport-related air pollution. The elements are expanding the urban areas, rise in the commuting time, and massive traffic congestion. The trends in such contributing factors are likely to counteract the average enhancement of air quality, basically about specific gaseous pollutants. It is indicated by Barth & Boriboonsomsin (2008) that minimizing this pollution would reduce acute asthma attacks in children along with medical care. When there is a decline in long-term air pollution levels, there is also a decline in the rate of bronchial hyperreactivity in yearly trends in the death from all causes along with respiratory and cardiovascular diseases. Such types of decreases tend to be linked with gains in life expectancy.

EPA (2015), according to initial estimates, it has been made evident that tens of thousands of deaths in a year tends to be linked with transport-related air pollution in the region. It is using a traffic management system that can be considered as one of the primary tools for minimizing the exposure of the residents belonging to the urban areas. Along with these, the coordination of the environmental and health considerations in urban planning can be enhanced. Urban planning would make use of integrative measures that lower the rate of emission, such as the promotion of service-oriented and clean public transport, highly efficient transport. It has been revealed by Dales (2014) that different technologies help in lowering the emission levels taking place from traditional vehicles. It is essential to promote their developments and enhanced control methods to remove gross pollutants and ill-maintained vehicles. It is alternative vehicle technologies and fuel substitutes that might lead to massive depreciation in the emission of hazardous air pollutants. As per Noland & Quddus (2006), there is a requirement to consider different measures that might impact travel. For instance, zoning offices, non-residential functions in urban highways, bicyclists from road traffic, and initiating various actions that might offer different disincentives to making use of private vehicles might lower the overall emission rate. These types of measures would pay more attention to a shift in favour of public transport and a rise in bicycling as well as walking that tends to possess positive impacts on health. It is also essential to have different control methods such as mandatory car inspections for minimizing the gross polluters and avoiding poorly maintained vehicles.

2.3. Recommendations for controlling traffic-related air pollution

It can be mentioned by Berglind & et al. (2009) that urban areas are considered to be the hot spots for human exposure to the air pollution that takes place basically from road traffic. It is significant to comprehend the efforts to control air pollution in urban areas. By the end of 2050, two-third of the globe's population is likely to live in urban areas by the end of the year 2050, which implies more people would be at risk of exposure to TRAP. Though there is high awareness regarding the link between traffic, exposure, air pollution, and severe health impacts, it has been identified that most of the cities in the globe find it difficult to meet the air quality standards that have been set to shield the public health. It is significant to understand the policy interventions, which implies a set of strategies or measures for attaining policy objectives. Public policies tend to minimize air pollution significantly; exposure tends to be underestimated because of personal choices. According to competent evidence, it is stated that there is a need to limit physical exertion outdoors during high pollution times and near air pollution sources, minimizing near-roadway exposures while commuting, making use of the air quality alert systems to plan activities, and also wearing of masks whenever needed. These strategies are likely to assist people in overcoming the negative impacts of air pollution. As per the views of Chuang & Et. Al. (2015) there are some more strategies that can comprise of avoiding cooking with solid fuels for minimizing the eruption of harmful smoke from it. Houses and offices need to possess portable air cleaners fitted with high-efficiency particulate air filters. It can further be stated that there is a need for well-created prospective studies for developing and validating interventions that shall prove to be advantageous to respiratory health. There is a need for proper urban planning so that there are concerns about air pollution. The city centers need to be appropriately designed so that living and working both becomes attractive. It shall avoid any types of a slump and also make active transport quite realistic. As revealed by Grabow & Et. Al., (2012) the individuals need to act actively to minimize the root causes of fossil fuel dependence. It can as well be stated that health care professionals need to assist vulnerable patients to shield themselves from the negative impacts of air pollution. Health care practitioners need to be equipped with up-to-date scientific evidence for prescribing, minimizing techniques to the patients. As per the views of Zanobetti & Et. Al. (2010) it shall permit the health care practitioners to influence their position as trusted messengers and thus take their responsibilities to educate and support preventives measures instead of merely offering reactive treatment. It is essential to shift from the car or any public transport use towards active transportation such as cycling and walking. It possesses enormous advantages from minimization in traffic volume and air pollution emission, thereby leading to health benefits. As per Henschel & Et. Al. (2012) it is also essential to make use of the up-to-date real-time information over local air quality such as news feeds and websites, mobile phone application for guiding route and timing. It is also noted that the children tend to be highly exposed to air pollution and possess a faster respiratory rate that leads to their exposure towards black carbon being relatively high. Children's direction can be minimized by avoiding intersections, queuing traffic, and walking over the least trafficked side of the road.

Chapter 3: Research Methodology

Research methodology deals with all processes and procedures applied by the researcher to answer the research questions (Kothari, 2013). It is essential to select a suitable research methodology to ensure the reliability and validity of the research study. The following section explains the research methodology that has been applied in this research study, including research design, data collection, and data analysis tools and techniques.

3.1 Design

Research studies are grouped into two main categories that include a systematic literature review and empirical analysis. This study involves the use of a systematic literature review as a chosen research design. Accordingly, a systematic literature review consists of conducting a research study to achieve the research aim and objectives by identifying and evaluating the existing literature on the issue being investigated in the study (Wallace & Wray, 2011; Knoll et al., 2018). It is important to note that the methods and tools employed in the systematic literature review are different from the empirical study. The key differences between the two are that the systematic literature review uses secondary data or existing literature relevant to the issue being studied in the research. In contrast, the empirical study involves using primary data collected directly from the field, analyzed using statistical tools and techniques (Knoll et al., 2018).

3.2 Data Sources

There is a bulk of published journals, articles as well as bibliographic databases. It is often very challenging for the researcher to locate and identify the most relevant literature competently and effectively. Notably, the research studies that involve the investigation of the complex issue like human health impact exposure to traffic-related air pollution, it requires the researcher to make considerable effort and thoughts in locating and identifying the relevant literature for the review purpose (Cooper et al., 2018; Knoll et al., 2018). Therefore, in this research study, only those databases were considered for the collection of data that were identified to be relevant to the research topic and issue. In this study, electronic databases like MEDLINE, CINAHL, EMBASE, PsycINFO, PubMed, and Google scholar were used for locating the relevant literature for conducting the systematic review. Accordingly, these databases index a large volume of peer-reviewed journals and articles on different fields of study and subjects (Haddaway et al., 2015). The use of these databases is thus considered to allow the researcher to gather vast knowledge and information related to air pollution and its impacts on human being's health conditions.

3.3 Inclusion/ Exclusion Criteria

After conducting a literature search across the different databases, a bulk of literature is obtained. However, not all literature is relevant to the research issue being investigated in the study. The researcher needs to sort out this literature to determine the most relevant literature for answering the research questions (Subramanyam, 2003). Hence, to sort-out this literature, it is important to define inclusion and exclusion criteria clearly. The section below defines the inclusion and exclusion criteria considered in this systematic literature review study.

Inclusion Criteria

This study included only those data sources if:

They are about perspective and cross-sectional studies on short-term and long-term exposure to traffic-related air pollution.

They are etiological research on various diseases caused because of exposure to air pollution, mainly focusing on traffic-related air pollution.

Exclusion Criteria

This study excluded data sources if:

They are exclusively focused on indoor air pollution exposure

They are unpublished documents and scientific papers

3.4 Selection of research papers

In this study, articles and journals were selected and finalized in three phases.

First Phase: In the first phase, the titles and abstracts of the articles and journals were carefully screened and examined based on defined inclusion and exclusion criteria.

Second Phase: The full text of the shortlisted articles and journals were critically evaluated against the predefined inclusion and exclusion criteria.

Third phase: The bibliography of the selected articles and journals were scrutinized, and the most relevant papers were evaluated against the inclusion and exclusion criteria

3.6 Data Analysis

Data analysis is considered; there are two broad types of data analysis techniques: quantitative and qualitative data analysis. In this research study, the qualitative data analysis technique has been applied because this data analysis technique is considered to be the most widely used data analysis technique in the systematic literature review study. Moreover, there are different qualitative data analysis techniques, including content analysis, narrative analysis, and grounded theory. This study involves the use of the narrative analysis technique. Accordingly, narrative analysis is an iterative approach for summarising the findings of the included articles and journals.

3.7 Data Analysis Tools

For keeping track of the research process, the useful data analysis tool is word processing software, including Microsoft Word, and spreadsheets are used. Data Analysis required for this research paper has been conducted using Microsoft excel and spreadsheets where the proper track of the collected information and data can be adequately maintained, and it further helps the researcher to analyse the collected findings critically.

3.8 Methods of Quality appraisal

This study uses the ‘CONSORT (Consolidated Standards of Reporting Trials) statement,’ which provides researchers with standard way and recommendations for reporting trial results and findings (Boutron et al., 2017). CONSORT statement has been used in this study for ensuring validity and improving the reporting style of the results of the trial results. Furthermore, the CONSORT statement has been used in the study because it helps the researcher ensure complete and transparent reporting Boutron et al., 2017). Also, this study uses the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analysis) statement. PRISMA statement is defined as an evidence-based minimum set of recommendations for reporting in systematic reviews (Welch et al., 2016). PRISMA statement is used in this study to improve the reporting of systematic reviews and help researchers in the appraisal of interventions and their interpretations (Welch et al., 2016).

3.9 Ethical Consideration

As the systematic review did not involve primary data collection, and there was no direct participation involved in this study. Hence, the systematic review will not have any ethical implications. However, a simple consideration application has been submitted for the approval of this research, where it is necessary to protect the secondary data's authenticity. The researcher duly filled the ethical form for the secondary research, where the validity and reliability of the collected data are managed well. The researcher ensured that the gathered data and information are utilized only for the research purpose, not for any other purpose. Additionally, the information from the secondary data sources was correctly cited with an appropriate reference list to maintain the authenticity of the research.

Chapter 4: Findings

The following table demonstrates the selected articles and journals.

The following table provides a description of the relationship between air pollution caused due to traffic and its impact on human health.

The following table demonstrates the findings and outcomes obtained from the chosen articles.

Chapter Five: Discussion

5.1 Overall Discussion

Once the relevant data has been gathered using literature review and findings attained from the systematic literature review, it becomes significant to have a proper discussion for achieving useful insights into it. The chief objective of the chapter has been to link the findings attained from secondary data with that of the literature review so that the research objectives can be easily achieved. It is using this chapter that there is a need for proper interpretation of the findings that have been attained from the research. The chief research question has been to determine the distinct health impacts of traffic-related air pollution on human beings. The research design that the study tends to follow has been a systematic review of the secondary sources of information. To analyze the data, different tools such as MS Word as well as MS excel has been utilized to keep track of data that has been gathered. It can be discussed about the findings of the study and literature review that air pollution along with its public health impacts is attaining huge concerns from environmental regulatory agencies, environmental health research agencies, industries, and the public. The quality of the air, either indoors or outdoors, tends to be linked with morbidity and mortality from different types of cardiovascular and respiratory diseases (Kwon & et al., 2017). Some of the common air pollutants are particulate matter, carbon monoxide, nitrogen dioxide, lead, polycyclic aromatic hydrocarbons. The danger of vehicles as being one of the primary sources of air pollution tends to be exacerbated by the fact that different harmful substance tends to enter into the air in human respiration areas. It can be revealed that atmospheric air can be one of the leading life-supporting components of the ecosystem. Pollution can be considered as one of the primary and permanent factors of impact on humans as well as the environment. The specific characteristics of the air pollution using vehicle emission can be located in the complex spatial structure of the urban highways, their immersion in the urban development, close propinquity to the recipient, and the low location of emission sources above the ground. Hence, the total share of the transport in the context of emission of pollutant in the atmosphere is equal to 35%-60%. On the other hand, it can be discussed that the corresponding share of the pollution in the surface air layer in most of the urban areas tends to be 70% to 90% (EPA, 2015). This leads to the fact that vehicles in different cities tend to develop sustainable and extensive areas where the sanitary and hygienic air pollution standards are exceeded most of the time. It can therefore be discussed about the findings of the research and the literature review that road transport can be categorized to be one of the most dangerous sources of pollution. Epidemiological research has demonstrated that external air pollution tends to support the use of premature mortality and morbidity. Health impact assessment of exposure to air pollution tends to be linked to city level adequate particle concentration. It tends to undervalue the health outcomes related to altering local traffic. Exposure towards traffic oriented air pollution might be assessed at high resolution using modeling levels of NO2 (Chuang & et al., 2015). It can be discussed about the literature review of the study and findings of the research that to mitigate air pollution issues, several efforts need to be taken into consideration to decrease the pollutants emission that arises from people. The citizens of the country might assist in the mitigation of the air pollutants using the overall change in the behaviours and through minimization of energy consumption in transportation, household, and supply. It can be discussed that because of the respiratory disorders, lack of oxygen in all the tissues of the human body is noted. Along with it, hazardous road transport compounds tend to be carried with blood, and it tends to be deposited in different organs of the body. The impacts of this contamination might be evident years later in chronic diseases or even as cancer. The changes that are linked with the adverse effects of vehicles tend to become global day by day. With the pace of time, they might lead to the collapse of the ecosystem that is prevailing on the planet and would affect the lives of people, air as well as the atmosphere to a great extent. The requirement to consider emissions from distinct sources, their mutual influence tends to place significant focus on the work of the environmental services in different cities. Ascertainment of the surface concentration of pollutants by computation tends to permit simplifying and speeding up of the calculation methods to attain a clear picture of spreading of the harmful substances' emissions in the nearby areas about the actual scale of the site to evaluate the efficiency of different measures to minimize the emissions (Matz & et al., 2019).

One of the mitigation strategies for minimizing air pollution using the industrial sector has been implementing advanced technologies in industrial methods. Clean coal technologies can be utilized in an efficient manner that doesn't possess substantial environmental impact. It is quite possible to enhance the quality of the air by promoting online work and by avoiding unnecessary car movement on roads (Warburton & et al., 2010).

Chapter 6: Conclusion And Recommendations

6.1 Summary of the entire study

This particular chapter of the study aims at offering a summary of the whole survey. Air pollution can be considered one of the main threats to the environment, and it tends to impact everyone, such as humans, animals, cities, forests, and aquatic ecosystems. It generally takes place because of the presence of the toxic substance in the atmosphere that is generated by human activities. Although it becomes quite impossible to determine the whole extent of actual and the potential damages caused by all types of air pollution, some of them have been studied clearly. Humans' continual exposure to air pollutants tends to be responsible for the damage to human health. Air pollution can be considered as one of the main factors for human health conditions, thereby leading to allergies and different types of respiratory and cardiovascular diseases. The decline in air pollutant concentration might be attributed to minimizing emissions from vehicles and other industrial sources. Despite several enhancements in the overall air quality, the one spending massive time over and near major roads as well as highways such as commuters might be at high risk of exposure towards traffic-related air pollution. The children, seniors, and people with adverse health conditions might be more vulnerable to ill health impacts related to TRAP exposure. Most of the institutions serving the vulnerable population, such as elementary schools along with long-term care homes for seniors, are found to be located in TRAP exposed areas. Specific evidence tends to demonstrate that the minimization of such pollution may directly minimize acute asthma attacks and the requirement for related medical care among the children. Long term decline in the air pollution levels tends to be linked with gains in life expectancy rates and a reduction in bronchial hyperreactivity. Current policies might lead to enhanced air quality. Increasing traffic congestion along with the growth in the traffic volumes in most of the cities are weakening the advantages to urban air quality that leads to the introduction of cleaner fuels, strict emission limits on new vehicles, and road management. In case additional measures are not taken, then the annual nitrogen dioxide is expected to exceed present EU limit values of urban population because of the broad emission. Road transport would grow in the EU region in the coming decades. About technological issues, traditional diesel and petrol engines would dominate for another 10-20 years. The market share of diesel-fuelled vehicles would increase, and the carper kilometer's emission rate would minimize. It can be revealed that alternative vehicle technologies such as hybrid cars and fuel cells might not become too important in the coming years. It was expected that by the end of the year 2020, 20 % of conventional fuels need to be replaced by different substitutes such as biofuels, hydrogen, and natural gases. The dominant driving force for this initiative has been policies over climate change. Urban planning might try to attain integrative measures that would decline the rate of emissions, such as the promotion of highly efficient and clean public transport.

6.2 Recommendations

It can be recommended that the creation of technologies that would lower the emission levels of conventional vehicles needs to be promoted to a great extent. Control methods of proven efficiencies need to be utilized effectively. Substitute fuels tend to hold the potential for a future reduction in emissions of hazardous air pollutants. It can be recommended that some of the knowledge required to develop effective action is lacking behind. There is a need for research for quantifying the harmful impacts of transport-related air pollution on vulnerable groups such as older adults, children, and people already suffering from chronic conditions. Research is required to assess populations' exposure to air pollution and to transport-related air pollution that is rising. There is a need to ascertain what constituents of traffic emission tend to be accountable for observed health effects in the human populations that comprise of making studies regarding the role of the diesel emission as well as new pollutants.

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