Air Pollution Causes, Effects, and Solutions

How dirty air costs you money

Black smoke billows from a brick smokestack, fouling the sky above a stately oak tree.

Tahreer Photography / Getty Images

Air pollution is the presence of gases and solid particles that result in adverse health effects. They are either natural or human-made. Common air pollutants include ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate matter.

Here's what you need to know about air pollution, and what's being done about it.

The Threats of Air Pollution

The greatest threats to human health In the United States are ground-level ozone and airborne particles. The first threat, ground-level or "bad" ozone, is not emitted directly into the air. It is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.

The second threat comes from fine solid particles that mix with airborne liquid droplets to form particulate matter. The Environmental Protection Agency (EPA) highlights two kinds of particulate pollution: PM10 and PM2.5. PM10 are inhalable particles that are 10 micrometers in diameter or less. They include dust and mold. PM 2.5 are particles with diameters 2.5 micrometers or less. These include combustion particles, metals, and organic compounds. 

The EPA measures both gas and particulate air pollution with the Air Quality Index (AQI). It reports on five of the six air pollutants regulated by the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The AQI values range from 0 to 500. They are divided into six levels and the higher the number, the greater the risk. For example, 0 to 50 reflects “good” or "green" air quality, and 51-100 is “moderate” or "yellow." On the harmful end of the scale, an AQI of 301 to 500 is “hazardous” or "maroon," and it indicates emergency conditions affecting the entire population.

Health and Economic Effects of Air Pollution

The deadliest type of pollution is air pollution, according to the World Bank. It's the fourth leading risk factor for premature deaths worldwide. In 2013, those deaths cost the global economy $225 billion in lost labor. One reason the costs are so high is that nine out of 10 people in the world breathe highly polluted air. According to the World Health Organization, air pollution kills 7 million people each year. 

A 2020 study from the American Lung Association found that nearly half of Americans—some 150 million people—live where the air is unhealthy. Those who live with unhealthy air are at greater risk of asthma, lung cancer, and respiratory problems. Research in 2018 found air pollution is also linked to Alzheimer's and dementia. 

The Organisation for Economic Co-Operation and Development (OECD) estimates that, by 2060, air pollution will impose a 1% drag on global gross domestic product. In other words, air pollution is expected to cost the global economy roughly $2.6 trillion every year in the coming decades. As the economic costs increase, the toll on human life will, as well. The OECD also estimates that air pollution will cause as many as 9 million premature deaths every year by 2060.

Air pollution has some indirect costs, too, including unexpected impacts on school and work performance. A study found that the productivity of pear packers in Northern California was measurably lowered by certain types of air pollution. Another study found that Chinese call center workers take more breaks on high pollution days. A third study found that there were more absences in Texas school districts when carbon monoxide levels increased.

Sources and Causes of Air Pollution

More than half of all nitrogen oxide pollution is caused by burning fossil fuels for transportation. The transportation sector is also responsible for emitting cancer-causing particles like benzene, acetaldehyde, and diesel exhaust.

The nation’s 600 coal and oil-fired electric generating plants emit as much as 60% of the nation's toxic metal pollution. They spew 77% of the acid gases in the atmosphere, 50% of the mercury, and 62% of the arsenic.

Other sources of air pollution include industrial processes, agriculture, chemical production, and residential heating and cooking. Farms emit ammonia and methane from fertilizer and livestock. They combine with vehicle emissions to create particulates. A 2016 study found that particulate emissions from farms and ranches were greater than from any other man-made source. 

Volcanoes, wildfires, and dust storms are examples of natural sources of air pollution. However, unlike ongoing manmade sources of pollution, these sources are events—they only pollute while they are happening. 

Climate Change and Air Pollution

Climate change is making air pollution worse. Higher temperatures increase the amount of ozone in the lower atmosphere, for example. Even though ozone has been steadily increasing, the latest American Lung Association study on air pollution recorded a significantly sharp uptick in ozone levels compared with recent years. Wildfires are also getting worse—and creating more air pollution—as climate change worsens and exacerbates drought conditions.

Regulatory Actions to Reduce Air Pollution

In 1955, the passage of the Air Pollution Control Act marked the first time the federal government became concerned about combating air pollution. This act funded research to identify the causes and scope of air pollution. The first act to reduce air pollution was the Clean Air Act of 1963. This was followed by the regulation of interstate pollutant transport with the Air Quality Act of 1967.

The Clean Air Act of 1970 established air quality standards. It required states to meet those standards or face penalties. This act allowed states to control emissions from stationary sources and motor vehicles. The U.S. Environmental Protection Agency was established by Congress to implement these requirements.

The Clean Air Act had an immediate impact on the nation’s health. Clean air is important for good mental functioning, and one study found a significant relationship between the cleaner air after the passage of that act and the workforce participation and earnings of children born just the law took effect.

The 1990 amendments to the Act controlled 189 toxic pollutants. The amendments included rules that aimed to phase out the production of chlorofluorocarbons (CFCs), which deplete the Earth's ozone layer. A 2020 study by the National Aeronautics and Space Administration (NASA) found that the hole in the ozone layer is healing thanks to regulatory efforts on CFCs that began in the late '80s.

Unlike harmful ground-level ozone, stratospheric ozone is beneficial to humans. It absorbs harmful ultraviolet radiation. The radiation causes skin cancer, suppresses immune systems, and damages plant life.

In 2009, as President Barack Obama rolled out an auto bailout, the administration also moved to force automakers to improve fuel efficiency standards. These standards were finalized in 2012. It required vehicles to average 54.5 miles per gallon by the model year 2025. The goal was to cut 6 billion tons of carbon dioxide emissions from vehicles sold between 2012 and 2025. Those greenhouse gases cause global warming. The standards would also make the U.S. auto industry more competitive in foreign markets that already required stronger emission standards.

The Clean Power Plan was created to cut carbon pollution by 32% from 2005 levels. This plan, launched by the Obama administration in August 2015, would prevent 1,500 to 3,600 early deaths and 90,000 childhood asthma attacks each year.

To cut power plant emissions, the EPA set custom goals for each state. To get there, states could switch from coal to gas, renewables, or nuclear. They could impose Pigouvian taxes or carbon taxes.

On the state level, California leads the nation by setting higher standards for automobile emissions. Through the Clean Air Act, Congress allowed California to set its own standards. In 2002, it did so for light-duty vehicles. Thirteen other states, representing 40% of new vehicles sold, follow its lead. As a result, automakers design cars to meet California's standards, improving air quality nationwide.

However, President Donald Trump later moved to undo many Obama-era standards. On September 19, 2019, the Environmental Protection Agency announced it would relax vehicle efficiency rules and pre-empt any state-level attempts to impose stricter emissions standards on their own. This meant challenging California's laws.

The Biden Administration on Air Pollution

President Joe Biden campaigned on a platform that included calls for reduced air pollution. On his first day in office, he signed an executive order calling for an "emergency review" of all EPA actions during the Trump administration. While this review will likely result in the rollback of Trump-era policies, it may take a while for these efforts to be finalized in law. The boldest proposals from the administration are also expected to face legal challenges, which will slow their implementation.

The Bottom Line

Air pollution is deadly and costly, that’s why the World Bank regards it as the deadliest form of pollution. Although the U.S. and other governments have passed laws to address air pollution, the problem persists.

Individuals can reduce air pollution by making lifestyle changes. Auto use is a major polluter, so reducing personal auto use would have a significant effect. Limiting the consumption of beef and dairy products would reduce farm emissions.