Socioeconomics And Pollution: A Complex Relationship

Socioeconomic status can affect pollution exposure and susceptibility to its health effects. Research has shown that people with lower socioeconomic status are more likely to be exposed to higher levels of air pollution and experience greater health risks as a result. This is known as environmental inequality or injustice, and it disproportionately affects racial and ethnic minorities, as well as those with lower incomes and less education.

Various factors contribute to this disparity, including the location of pollution sources near disadvantaged communities, limited political power to influence land-use decisions, and individual characteristics such as health status, stress, and access to healthcare.

Socioeconomic status also influences an individual's susceptibility to the health effects of air pollution. For example, people with lower socioeconomic status may have poorer health, face more psychosocial stressors, and have less access to healthcare, making them more vulnerable to the adverse effects of air pollution.

Additionally, higher socioeconomic status can provide resources to mitigate exposure to air pollution, such as private transportation, indoor work environments, and improved housing conditions.

Research on the relationship between socioeconomic status and air pollution has primarily been conducted in North America and Europe, with limited studies from other regions like Asia, Africa, and New Zealand. The findings suggest that the distribution of air pollution and resulting health outcomes are often unequal across socioeconomic groups, with lower socioeconomic communities bearing a disproportionate burden.

Socioeconomic status and air pollution exposure

Socioeconomic status is a complex construct, with various indicators such as income, education, occupation, and poverty. Research has shown that low socioeconomic status is linked to higher exposure to air pollution, particularly in North America and some parts of the world. However, the relationship between socioeconomic status and air pollution exposure is more complex in Europe, with mixed findings. This review will explore the existing literature on the association between socioeconomic status and air pollution exposure, focusing on the distribution of air pollutants across different socioeconomic groups.

North American Studies

Most North American studies have consistently found that lower socioeconomic status individuals and communities are exposed to higher concentrations of air pollutants. For example, studies have shown that areas with lower socioeconomic status have higher levels of particulate matter (PM), nitrogen dioxide (NO2), and other criteria air pollutants. However, there are some exceptions to this pattern, with a few studies finding higher pollutant concentrations in higher socioeconomic areas, particularly in New York City, Toronto, and Montreal. These exceptions may be due to the clustering of high socioeconomic individuals around busy roadways, which often offer scenic views and better access to urban amenities.

European Studies

The findings from European research on the association between socioeconomic status and air pollution exposure are more varied. Some studies have found a positive association between socioeconomic status and air pollution, while others have found a negative association or no association at all. For instance, a study in Strasbourg, France, found that only the highest socioeconomic quintile had lower NO2 concentrations, while the other quintiles had similar concentrations. Additionally, a European-wide analysis revealed non-linear trends, with middle-income populations having lower PM10 concentrations than both higher and lower-income groups. The choice of socioeconomic metrics and the unit of analysis also seem to play a role in the mixed findings.

Studies from Other Regions

Limited research from other parts of the world, including New Zealand, Asia, and Africa, has shown a similar trend to North America, with lower socioeconomic status groups experiencing higher exposure to air pollution. For example, studies in New Zealand found that low-income and high-deprivation neighborhoods had higher PM10 concentrations compared to higher socioeconomic areas. The lone study from Africa, conducted in Ghana, also indicated an inverse association between community socioeconomic status and air pollution levels.

Methodological Considerations

It is important to consider the methodological approaches used in the studies, as they can impact the findings. The unit of analysis, such as census tracts, cities, or regions, can influence the results, with smaller geographic units often providing more reliable and accurate data. Additionally, the choice of statistical methods, such as regression models, and the adjustment for potential confounders, such as population density and land use, can also affect the findings.

In conclusion, the existing literature suggests that socioeconomic status plays a role in air pollution exposure, with lower socioeconomic status groups generally facing higher exposure to air pollutants. However, the relationship between socioeconomic status and air pollution exposure is complex and influenced by various factors, including geographic location, methodological choices, and the specific pollutants studied. Further research is needed, particularly in regions with limited data, to better understand the association between socioeconomic status and air pollution exposure and to inform policy interventions aimed at reducing environmental inequalities.

Air pollution and health effects

Air pollution is a risk for all-cause mortality as well as specific diseases. The specific disease outcomes most strongly linked with exposure to air pollution include stroke, ischaemic heart disease, chronic obstructive pulmonary disease, lung cancer, pneumonia, and cataract (household air pollution only).

There is suggestive evidence also linking air pollution exposure with increased risk for adverse pregnancy outcomes (i.e. low-birth weight, small for gestational age), other cancers, diabetes, cognitive impairment and neurological diseases.

The children, elderly and pregnant women are more susceptible to air pollution-related diseases. Genetics, comorbidities, nutrition and sociodemographic factors also impact a person’s susceptibility to air pollution. Maternal exposure to air pollution is associated with adverse birth outcomes, such as low birth weight, pre-term birth and small for gestational age births.

Socioeconomic status also appears tied to greater harm from air pollution. Multiple large studies show evidence of that link. Low socioeconomic status consistently increased the risk of premature death from fine particle pollution among 13.2 million Medicare recipients studied in the largest examination of particle pollution-related mortality nationwide.

People in low socioeconomic neighborhoods and communities may be more vulnerable to air pollution because of many factors. Proximity to industrial sources of air pollution, underlying health problems, poor nutrition, stress, and other factors can contribute to increased health impacts in these communities.

A growing body of evidence suggests that air pollution may affect diabetes and neurological development in children.

Air pollution and individual and neighbourhood socioeconomic status

Socioeconomic status (SES) is a complex construct, often operationalised with a variety of different measures, including income, education, and occupation.

North America

Most North American studies have shown that areas where low socioeconomic status (SES) communities dwell experience higher concentrations of criteria air pollutants. However, some studies have found the opposite association, with higher SES census tracts having higher concentrations of pollutants. Other North American studies have found differences by pollutant, with high poverty clusters in Los Angeles having similar NO2 and PM2.5 concentrations compared to low poverty clusters, but higher concentrations of other pollutants. Several North American studies also found that higher SES groups are exposed to higher concentrations of O3 compared to lower SES groups.

Europe

Findings in the European literature were quite mixed. Several studies found non-linear patterns of inequality, with only the high SES quintile having lower NO2 concentrations, compared to the other 4 quintiles that had similar concentrations. Other studies found the choice of SES metric relevant to findings, where some SES measures were positively associated with air pollution and others negatively. A few European studies from England and Sweden found patterns of inequality similar to those seen in the U.S.

New Zealand, Asia, and Africa

Studies from New Zealand, Asia, and Africa also showed negative associations between SES and air pollutants. The lone study to address air pollution inequalities in Africa was from Ghana, which found community SES was inversely associated with both PM2.5 and PM10.

Methodological issues

The appropriate unit of analysis and the accompanying modifiable areal unit problem (MAUP) in environmental inequality studies has been discussed. Very few studies rely exclusively on larger geographic units such as counties or cities. Most of the studies use something similar to or smaller than a U.S. census tract. A few studies use very small geographic areas such as parcel data, building of residence, or British postcode.

Many of the studies reviewed use a spatial regression approach to evaluate the association between SES and air pollution. However, among studies using regression methods, many do not use methods that account for the clustering of air pollutants across space.

Air pollution exposure assessment

Most of the studies reviewed used either dispersion models, land use regression (LUR) models, or a hybrid approach to predict air pollution at unmeasured locations. Very few studies use proximity-based or weighted approaches.

SES metrics

SES is a complex construct that has been operationalised with a variety of different measures, including income, education, and occupation. SES measures take different forms in less industrialised countries, where housing type, water and electricity access, and assets in the form of cattle and televisions are often used. In terms of area-level measures of SES, the British have led the way in articulating the need for a deprivation index, an index composed of several individual metrics to measure a relative lack of resources along several dimensions.

Air pollution and environmental justice

Air pollution is a pressing issue that disproportionately affects communities of colour and low-income communities. Research has shown that certain populations are more susceptible to air pollutants, with residents of low-income communities experiencing increased health impacts from air pollution due to various environmental, social, and economic factors.

Factors Leading to Disproportionate Impact

People of colour are 1.5 times more likely to live in areas with poor air quality than white people. This disparity is caused by various factors, including racism, class bias, housing market dynamics, and land costs, which result in pollution sources being located near disadvantaged communities. Additionally, low-income neighbourhoods often have major roadways, ports, and factories nearby, increasing exposure to harmful pollutants.

Health Effects

The health effects of air pollution are more pronounced in older adults, children, pregnant women, and people with pre-existing cardiopulmonary disease. These vulnerable groups are at a higher risk of developing asthma, reduced lung function, cardiovascular disease, and premature death due to air pollution.

Addressing Environmental Justice

To address environmental justice, the American Lung Association advocates for the formulation and enforcement of health and environmental policies that reduce air pollution in these communities. They also emphasise the need to prioritise clean-up efforts in areas near highways, ports, industrial boilers, and power plants.

Research and Initiatives

The US Environmental Protection Agency (EPA) is conducting research to better understand the relationship between poor air quality and health disparities. They are also developing strategies to reduce the impacts of poor air quality and providing communities with tools and information for air quality monitoring.

Air pollution disproportionately affects communities of colour and low-income communities, leading to various health issues and an economic burden. Addressing environmental justice requires targeted policies and initiatives to reduce harmful emissions and exposures in these vulnerable communities.

Air pollution and health inequalities

Several studies have found a correlation between air pollution and mortality rates, with people of colour and low SES individuals experiencing higher rates of premature death from fine particle pollution. Furthermore, air pollution can worsen existing health conditions, such as asthma and diabetes, which are more prevalent in certain racial and ethnic groups.

The impact of air pollution on health is not limited to physical ailments but also extends to mental health. Stress and psychosocial factors associated with living in disadvantaged communities can further increase susceptibility to the negative health effects of air pollution.

Addressing air pollution and health inequalities requires a multifaceted approach. It involves reducing emissions and pollution sources near vulnerable communities, improving access to healthcare and healthy food options, and promoting equitable access to quality education and economic opportunities.

Overall, the evidence suggests that air pollution disproportionately affects vulnerable populations, and mitigating these health inequalities requires targeted interventions and policies that address the underlying social and environmental factors.

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