Air Pollution's Worst Offenders: A Global Crisis

Air pollution is a significant health problem in modern industrial society, causing approximately 7 million premature deaths annually and reducing the average life expectancy of those affected by around 2.3 years. According to the World Health Organization (WHO), only seven countries, or less than 4% of the world, met the air quality standards in 2023. Bangladesh was ranked as the most polluted country in 2023, with pollutant levels exceeding the safe annual limit by more than 15 times. Other countries with poor air quality include India, Pakistan, Tajikistan, Burkina Faso, and Vietnam, with Hanoi being specifically mentioned as a highly polluted city. China's air pollution data is questionable, with some reports estimating through satellite images and studies, while others rely on sparse CCP data. Developing countries, particularly in Africa, South America, and Southeast Asia, tend to have higher air pollution levels due to their reliance on fossil fuels, coal power plants, and solid fuels for cooking, heating, and lighting.

Los Angeles, California: worst for ozone pollution

Los Angeles, California, has the worst ozone pollution in the United States. According to the 2019 State of the Air report, which compared data across 229 metropolitan areas, Los Angeles has the worst ozone air pollution in the country. The report also noted that the LA-Long Beach region ranked highest for ozone pollution.

Ozone is a gas pollutant formed when sunlight reacts with nitrogen oxides and organic substances. Vehicle exhaust contains both the nitrogen oxides and reactive organic substances needed to form ozone, so traffic is frequently identified as a leading source of ozone pollution. The Southern California region has long been particularly susceptible to bad ozone levels due to the combination of warm weather and harmful pollutants from fuel emissions. The summer months of June, July, and August tend to be more polluted than other months for both PM2.5 and ozone. This is because of drier conditions, less rainfall, higher temperatures, and a higher frequency of wind-blown dust and wildfires fanned by the Santa Ana winds.

The 2020 wildfire season, which saw four of the five largest wildfires in California's history, also contributed to the increase in ozone pollution in Los Angeles. The record-breaking wildfire season resulted in 41 out of 45 counties in California showing increased particle pollution days. The report also found that climate change is degrading air quality across the country, with rising temperatures and other impacts associated with climate change contributing to increased ozone pollution and more frequent and intense wildfires.

The health implications of ozone pollution are significant. Ozone, along with PM2.5, forms the smog that Los Angeles is often known for. Exposure to ozone can lead to respiratory infections and inflammation and has been linked to premature death. According to the County of Los Angeles Public Health Department, one in ten children have been diagnosed with asthma, and the overall risk for cancer has increased by 900 for every million, as reported by the South Coast Air Quality Management District. Lower-income communities and communities of color are disproportionately affected by ozone pollution, as they are more likely to live near sources of harmful truck, train, and shipping pollution.

Bakersfield, California: worst for short-term particle pollution

Bakersfield, California, has been ranked as the worst in the United States for short-term particle pollution. This is due to a variety of factors, including emissions from oil refineries, agriculture, industry, rail freight, and road traffic. Together, these sources create one of the country's worst concentrations of air pollution.

The American Lung Association's State of the Air 2016 report highlighted the poor air quality in Bakersfield, with an average reading of 40.5 micrograms per cubic meter of fine particulate matter (PM2.5) in a 24-hour period. PM2.5 refers to particulate matter that is 2.5 micrometers in diameter or less, small enough to be absorbed into the bloodstream upon inhalation. These particles contribute to a range of pulmonary and cardiovascular diseases and can affect nearly every organ system in the body.

The geography and topography of the San Joaquin Valley, where Bakersfield is located, also play a role in the city's poor air quality. The valley is surrounded by mountain ranges, creating a bowl-like shape that makes the area particularly vulnerable to smog formation and the concentration of pollutants when weather conditions are unfavourable.

The health impacts of Bakersfield's air pollution are significant, with a high prevalence of respiratory and cardiovascular diseases in the area. It is estimated that about 70,000 people in the wider metro area have asthma, 40,000 have cardiovascular disease, and 27,000 have chronic obstructive pulmonary disease.

Despite the efforts of local activists and improvements in air quality in recent years, Bakersfield continues to struggle with the negative consequences of air pollution. The political dynamics and influence of the local pollution control district have also posed challenges to implementing effective legislation and regulations to address the issue.

Climate change: increases risk of wildfires, which cause particle pollution

Air pollution is one of the biggest health problems of modern industrial society and is responsible for more than 10% of all deaths worldwide (that's nearly 4.5 million premature deaths in 2019, according to The Lancet). It can affect almost every organ and system in the human body and also negatively affects nature.

The sources of air pollution are varied and can be both natural and manmade. Natural sources include volcanic activity, wildfires, dust, and sandstorms. The impact of natural sources depends on the local environment. For example, locations near large deserts are more susceptible to windblown dust and sand, while forested areas are more prone to wildfires. Manmade sources are the leading contributors to air pollution in cities and include various forms of combustion, such as transportation and industrial businesses.

Climate change and air pollution are closely linked and influence each other. Human activities, such as burning fossil fuels, transportation, and industrial processes, release greenhouse gases and black carbon emissions, which fuel climate change. These pollutants trap heat in the atmosphere, causing global warming and erratic weather patterns. This, in turn, increases the risk of wildfires, especially by exacerbating drought conditions that make forests more vulnerable to fires.

Wildfires are a significant contributor to air pollution. They release a range of pollutants into the atmosphere, including black carbon, carbon monoxide, nitrogen oxides, and particulate matter. These pollutants can combine with existing air pollution, further increasing the harmful effects on human health and the environment. For example, the 2023 wildfires in Chile caused a drastic increase in short-term ozone exposure, leading to a declared state of environmental emergency in the affected regions.

The relationship between climate change, wildfires, and air pollution forms a vicious cycle. As climate change increases the likelihood of wildfires, the resulting fires further contribute to air pollution, which in turn exacerbates climate change. Breaking this cycle requires a joined-up approach that addresses the interconnectedness of these issues.

Nearly half of Americans live in places with unhealthy pollution levels

Air pollution is a critical global health issue, causing over 4.5 million premature deaths in 2019, according to The Lancet. It is a particular concern in developing countries, where environmental standards are often not met. Natural sources of air pollution include volcanic activity, wildfires, dust, and sandstorms, while manmade sources, such as combustion from transportation and industrial activities, are the leading contributors in cities.

In the United States, nearly half of Americans, approximately 156 million people, live in areas with unhealthy levels of air pollution. This issue is highlighted in the American Lung Association's (ALA) "State of the Air" 2025 report, which found that 46% of the population resides in places with failing grades for ozone or particle pollution. This is a significant increase from the previous year's report, with 25 million more people breathing unhealthy air.

Several factors contribute to the worsening air quality in the US. Climate change, extreme heat, drought, and wildfires are among the primary reasons for the deteriorating air quality across the country. The impact of these factors is evident in the increase in ozone and particle pollution, which pose significant health risks to those exposed.

Some communities are disproportionately affected by air pollution. According to the ALA report, Hispanic individuals are nearly three times more likely than white individuals to live in communities with failing grades for air quality. Additionally, people of color and those with lower incomes are more vulnerable to the negative health impacts of air pollution. The report also criticizes cuts to the Environmental Protection Agency (EPA), stating that reductions in federal staff, programs, and funding are leaving families more vulnerable to harmful air pollution.

The cities with the worst annual pollution in the US include Casper, Wyoming; Urban Honolulu, Hawaii; St. George, Utah; Anchorage, Alaska; and Colorado Springs, Colorado. Bakersfield, California, has the worst level of year-round particle pollution for the sixth consecutive year, while Los Angeles continues to rank highly for ozone pollution. These findings underscore the urgent need to address air pollution and protect the health and well-being of communities across the country.

Pollution disproportionately affects communities of colour

Air pollution is a critical global health issue, responsible for over 10% of all deaths worldwide. It is a particular problem in emerging and developing countries, where environmental standards are often not met. However, it is important to recognise that the burden of air pollution is not evenly distributed. Poorer people and racial and ethnic minority groups are often disproportionately impacted by air pollution.

In the United States, people of colour are exposed to higher levels of particulate air pollution, regardless of income level or region. This includes African Americans, Hispanics, Asians, and other racial minorities. Fine particulate matter (PM2.5) is a regulated pollutant that poses serious health risks, including lung and heart problems. The sources of this pollution vary and include industry, agriculture, vehicles, construction, and residential sources.

Systemic racism has played a significant role in this disparity. Housing policies and other factors have led to people of colour being pushed into areas with higher pollution levels. Pollution sources, such as industrial facilities, power plants, and major roadways, tend to be located near disadvantaged communities, increasing the exposure of people of colour to harmful pollutants. This has resulted in marginalised communities, particularly those with larger African American populations, experiencing higher rates of premature deaths and asthma attacks due to particle pollution.

Furthermore, socioeconomic status is closely linked to the harm caused by air pollution. Multiple studies have shown that low socioeconomic status increases the risk of premature death from fine particle pollution. This is often compounded by other factors such as chronic stress due to discrimination, which can further impact the health of marginalised communities.

Addressing these disparities requires recognising the systemic racism that has contributed to the problem. Regulations and policies must be designed to combat environmental injustice and reduce the exposure of marginalised communities to air pollution. Incentivising vehicle electrification and removing high-emitting combustion engine vehicles can also help improve air quality and reduce health burdens on disadvantaged groups.

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