Air Pollution's Dark Reflection Across America

Air pollution is a pressing issue in the United States, with nearly half of the population exposed to unhealthy levels of pollution, according to the American Lung Association's 2025 State of the Air report. While air quality has improved since the 1970s due to regulations like the Clean Air Act, certain areas still struggle with poor air quality, threatening the health and welfare of Americans. The report highlights the impact of climate change, with extreme heat and wildfires contributing to increased particle pollution and ozone levels, affecting millions. Additionally, the COVID-19 pandemic has brought new challenges, with air pollution exacerbating respiratory issues. The U.S. Environmental Protection Agency (EPA) plays a crucial role in monitoring and regulating air pollution, but faces threats from staffing and funding cuts. Furthermore, the issue of air pollution reflects racial inequalities, with communities of color disproportionately exposed to unhealthy air and more vulnerable due to higher rates of chronic conditions.

The impact of racist policies from the 1930s

In the 1930s, in the wake of the Great Depression, the US federal government graded neighbourhoods in hundreds of cities for real estate investment. Black and immigrant areas were typically outlined in red on maps to denote risky places to lend. This practice, known as redlining, entrenched discriminatory practices whose effects are still felt today.

A 2022 study found that urban neighbourhoods that were redlined by federal officials in the 1930s tended to have higher levels of harmful air pollution eight decades later. The study, published in the journal Environmental Science & Technology Letters, looked at neighbourhoods in 202 cities and their exposure to two pollutants harmful to human health: nitrogen dioxide and dangerous microscopic particles known as PM 2.5. The study found that people in redlined neighbourhoods experienced levels of nitrogen dioxide that were twice as high as in the areas that federal surveyors in the 1930s designated as "best" or most favoured for investment.

The lead author of the study, Haley M. Lane, said she was surprised to find that the differences in air pollution exposure between redlined and better-rated districts were even larger than the well-documented disparities in exposure between people of colour and white Americans. Lane noted that there are many other effects creating these disparities, and the delineations by redlining are just one factor.

Joshua S. Apte, an assistant professor of civil and environmental engineering at Berkeley who worked on the study, said he had assumed the differences between neighbourhoods would be more pronounced in certain regions, like the South. Instead, the patterns he and his colleagues found were remarkably consistent across the country. "This history of racist planning is so deeply ingrained in American cities basically of any stripe, anywhere, "We went looking for this regional story, and it’s not there."

The racial makeup of some cities has also changed over the past decade due to gentrification and other factors. More research is needed to determine how this has affected pollution inequalities. However, disparities in Americans' exposure to air pollution in those cities are often evident. For example, concrete plants often end up being built in minority neighbourhoods because developers believe people there are less likely to object. Language barriers deter some residents from participating in public hearings.

The Clean Air Act's effectiveness

The Clean Air Act, a comprehensive federal law, has been instrumental in reducing air pollution in the United States over the past 50 years. The Act, enacted in 1970, gave the Environmental Protection Agency (EPA) the authority to regulate air pollutants and polluting industries.

The EPA has set and implemented emissions standards to control pollution from various sources, including vehicles, heavy-duty trucks, buses, construction and farm equipment, and marine engines. These standards have led to the adoption of modern automotive technologies, resulting in cleaner and more efficient cars. The EPA's efforts have also sparked innovation in the industry, with companies developing new technologies to meet the standards.

The Clean Air Act Amendments of 1990 were a significant milestone, targeting four key areas: acid rain, urban air pollution, toxic air emissions, and ozone depletion. The Acid Rain Program, for example, has led to a substantial reduction in sulfur dioxide and nitrogen dioxide emissions. The 1990 amendments also required the EPA to identify industrial sources of nearly 190 toxic air pollutants and implement appropriate pollution controls.

Since the Clean Air Act was enacted, the combined emissions of criteria and precursor pollutants have dropped by 78%. Air quality has improved despite increases in population, economic activity, and vehicle miles traveled. The EPA's efforts have resulted in healthier air for Americans and improved public health.

However, challenges remain. Despite the progress, approximately 140 million people in the US lived in counties with pollution levels above the primary NAAQS in 2023. Extreme weather events, such as heatwaves, droughts, and wildfires, are also contributing to worsening air quality in some regions. The EPA is now focusing on addressing the critical challenge of climate change, with the transportation sector being one of the largest sources of carbon pollution.

The EPA's role in protecting Americans' health

Air pollution is a serious environmental health hazard, and it is a major threat to global health and prosperity. It is responsible for millions of deaths each year globally, and this number has increased over the past two decades. In the United States, air pollution continues to harm people's health and the environment, despite dramatic progress in cleaning the air since the 1970s.

The US Environmental Protection Agency (EPA) plays a vital role in protecting Americans' health from the harmful effects of air pollution. The Clean Air Act, which was established in 1970, defines the EPA's responsibilities for improving and protecting the nation's air quality and the stratospheric ozone layer. The Act has been successful in reducing national emissions of air toxics and common pollutants such as particles, ozone, lead, carbon monoxide, nitrogen dioxide, and sulfur dioxide. The EPA has achieved this through various initiatives and partnerships, such as the National Clean Diesel Campaign, Clean School Bus USA, and the SmartWay Transport Partnership.

The EPA's research provides critical information to understand the health impacts of air pollution and to develop regulations to protect public health. For example, EPA research has shown that air pollution exposure is associated with oxidative stress and inflammation in human cells, which can lead to chronic diseases and cancer. The EPA has also established that short-term exposure to higher levels of outdoor air pollution is linked to reduced lung function, asthma, and cardiac problems. This research informs the EPA's Integrated Science Assessments and helps make regulatory decisions on the National Ambient Air Quality Standards (NAAQS).

In addition to research and regulation, the EPA also works to reduce air pollution through voluntary partnership programs and regulatory programs. For instance, the Clean Air Act partnership programs have been successful in reducing conventional air pollution, improving energy efficiency, and reducing oil imports. The EPA also provides flexibility to industries on controlling emissions while maintaining accountability for achieving emissions reductions.

Despite the EPA's significant contributions to protecting Americans' health, its work is currently under threat due to staffing and funding cuts. These cuts endanger the EPA's ability to continue its vital research and regulatory functions, which are essential for safeguarding public health and the environment from the harmful effects of air pollution.

The impact of climate change

Climate change and air pollution are closely intertwined issues. While climate change affects air quality, certain air pollutants can also contribute to climate change.

Climate change has led to an increase in ground-level ozone, a harmful greenhouse gas that contributes to climate change by trapping heat in the atmosphere. The 10 warmest years on record have occurred in the last decade, and temperatures are expected to continue rising. This warming is caused by the increase in greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, in the atmosphere. These gases are produced by human activities, including burning fossil fuels, vehicle exhaust, industrial sources, and agricultural emissions. The warming climate has resulted in more frequent and severe heat waves, which further increase ground-level ozone and contribute to poor air quality.

In addition to higher temperatures, climate change has also caused an increase in pollen production and allergen potency. Rising temperatures and carbon dioxide levels lengthen the pollen season and increase the amount of pollen produced by plants, leading to worsened pollen allergies. This has significant health implications, particularly for individuals with asthma, as pollen peaks can trigger asthma attacks.

Climate change has also led to an increase in extreme weather events, such as flooding, storm surges, and droughts. These events can have indirect impacts on air quality. For example, flooding and storm surges can result in water damage to buildings, creating damp conditions that foster the growth of harmful pollutants like mold and bacteria. Additionally, droughts can increase particulate matter in the air, causing air quality issues.

Furthermore, climate change has contributed to more frequent and intense wildfires, which produce smoke that lowers air quality and poses risks to human health. The impact of climate change on air quality varies by region, with certain areas being more vulnerable to specific climate-driven changes in weather conditions.

Mitigation Efforts

Efforts to reduce air pollution can also help mitigate climate change. Initiatives such as the Clean Air Act and the Clean Power Plan have successfully reduced harmful emissions from transportation, power plants, and manufacturing. Additionally, regulatory measures, partnership programs, and individual actions can play a role in reducing air pollutants and greenhouse gas emissions, thereby improving air quality and mitigating climate change.

The air pollution inequalities

Air pollution inequality in the United States disproportionately affects racial and ethnic minorities, with people of colour experiencing higher levels of air pollution than their white counterparts. This disparity is evident across income levels and regions, indicating that race is a significant factor in exposure to air pollution. Studies have found that African Americans, Hispanics, Asians, and other people of colour are exposed to higher levels of harmful particulate matter (PM2.5) in the air they breathe, which can lead to serious health issues, including lung and heart problems.

While economic inequality has been suggested as a potential root cause of environmental inequality, recent research challenges this notion. Data suggests that the relationship between income, wealth, and pollution exposure is relatively weak. For example, non-Hispanic Black individuals face higher pollution exposure than non-Hispanic White individuals at every income level. Additionally, large income windfalls only lead to modest reductions in pollution exposure, indicating that addressing income inequality alone may not significantly reduce environmental inequality.

Residential segregation plays a significant role in the air pollution inequalities faced by racial and ethnic minorities. Due to historical and systemic racism, people of colour are more likely to live in areas with greater exposure to air pollution. This pattern is observed across the United States, with higher-than-average Black, Asian, and Hispanic or Latino populations experiencing higher levels of PM2.5 pollutants. Socioeconomic status also contributes to the inequality, as low-income communities are often located near pollution sources and face greater health risks from fine particle pollution.

Furthermore, certain demographic factors can exacerbate the impact of air pollution on specific groups. For instance, the elderly, African Americans, Mexican Americans, and people living near central cities have higher rates of diabetes, making them more vulnerable to the health effects of air pollution. Additionally, communities with higher unemployment rates or higher reliance on public transportation have been found to be at greater risk of premature death from air pollution.

Addressing air pollution inequalities requires a comprehensive understanding of the interplay between race, ethnicity, income, and geographic location. While the EPA aims to provide equal protection from environmental hazards, more research is needed to fully grasp the complex dynamics of air pollution inequalities and develop effective solutions.

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