- Recent and ongoing wildfires have highlighted how climate change contributes to poor air quality.
- Air pollutants are also caused by vehicle emissions, and industrial and agricultural practices, and may also arise indoors.
- Each year, an estimated 7 million premature deaths are attributed to air pollution.
- Breathing in harmful particulate matter can increase the risk of health concerns, including heart disease, respiratory distress, and cancer.
- You can reduce your exposure to air pollution by wearing a face mask or refraining from exercising outdoors when the Air Quality Index (AQI) reaches high levels.
On average, adults take 12–20 breaths per minute. The air we breathe contains much more than vital oxygen — it comprises toxins and particulate matter (PM), high levels of which can have a detrimental effect on health.
Poor air quality is exacerbated daily by multiple pollutants, which could increase the risks of health concerns ranging from heart disease to COPD, cancer, and even dementia. Unhealthy air quality is also associated with premature death.
We might not give the air we’re breathing much thought until we see noticeable changes in the air around us — during wildfire season, for instance, when the sky turns burnt orange and the Air Quality Index (AQI) reaches dangerously high levels.
“Many people may not think about the fact that air that looks clean (has good visibility) still contains pollutants that are harmful to health,” said Shahir Masri, ScD, a specialist in air pollution exposure at the Department of Environmental & Occupational Health at the University of California, Irvine.
If you’re concerned about the health effects of air pollution, it’s important to understand how to protect yourself.
Particulate matter (PM), also known as atmospheric aerosol particles, contain microscopic solid or liquid molecules that are found in the air we breathe.
One type of
“The reason [PM2.5 particulates] are particularly virulent is they float with the air through your upper respiratory system, deep into your lungs into the alveoli [air sacs], where they lodge,” explained Russell Dickerson, PhD, a researcher and professor at the Department of Atmospheric and Oceanic Science at University of Maryland, College Park.
Dickerson explained that once PM2.5 matter is breathed in, it can pass through the sacs’ membrane and into your blood. As a result, inflammation and oxidative stress can occur, leading to various health concerns.
According to Neil Donahue, PhD, a professor of chemical engineering at the College of Engineering at Carnegie Mellon University, PM2.5 “causes more than 10% of all deaths around the world.”
Donahue told Healthline that air quality in the United States is “really quite good compared to other places,” but noted the number of related deaths remains high.
He said around 3.5 million deaths occur in the U.S. each year, 100,000 of which (about 3%) can be attributed to air pollution.
“[This is] not that far off the pandemic and way more than homicide and automobile deaths combined,” Donahue noted.
Air pollution from dangerous particulate matter like PM2.5 could have significant effects on health and well-being, which may vary depending on where you live.
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What’s more, heart disease has been found to occur from long-term PM2.5 exposure, even when pollution levels are below ambient levels of 12 micrograms (μg) per cubic meter (m3).
Huang said another major health concern of air pollution exposure is respiratory disease, the short-term impacts of which may include:
- shortness of breath
Air pollution exposure may also lead to and exacerbate chronic concerns, such as chronic obstructive pulmonary disease (COPD).
For instance, one meta-analysis found that a 10 μg/m3 increase in PM2.5 led to higher hospital visits and admissions among COPD patients. Huang added that air pollution may also lead to respiratory conditions like asthma and lung cancer.
Lung cancer isn’t the only cancer associated with air pollution.
Neurological, cognitive, and mental health
Air pollution may also impact brain health in various ways.
For instance, recent studies show close links between dementia and extended PM2.5 exposure.
There are also effects on cognitive well-being.
While it’s impossible to avoid air pollutants entirely, you can take measures to help minimize your exposure.
According to experts like Masri and Jennifer Vanos, PhD, a scientist at the Julie Ann Wrigley Global Futures Laboratory and associate professor in the School of Sustainability at Arizona State University, these include:
- Wear a face mask outdoors when pollution is high. Make sure it sits tightly against the face; facial hair will prevent effective sealing.
- Don’t exercise outdoors if pollution is bad, and always try to avoid exercising alongside major roads.
- Use an air purifier to reduce pollution in the home (ensure it is suitable for the room size). Place somewhere you spend a lot of time, such as the bedroom, and ensure windows are closed.
- Be aware that events with lots of fireworks (such as the Fourth of July in the U.S.) can increase air pollution.
- Use tape around older windows to seal gaps and prevent fine PM from seeping through.
- If you’re in high pollution areas, change your clothes after returning home.
- When using central air conditioning, switch the setting to recirculate air.
- If possible, live away from industrial areas and major roads.
The United States Environmental Protection Agency (EPA) and the World Health Organization have different levels of “maximum” acceptable air pollution.
EPA states PM2.5 levels should not exceed 35 μg/m3 in 24 hours. WHO’s limit is lower, at 15 μg/m3 per 24 hours.
The situation is consistently worse in other countries. For instance, in India, the average individual is regularly exposed to PM2.5 at 75-100 μg/m3.
However, without smog or significant smoke, it’s almost impossible to visualize how much pollution is in the air.
To check PM2.5 and ozone levels in your area, the U.S. government maintains an Air Quality Index (AQI) called Air Now.
“[Air Now] allows residents to input their zip code to identify their local air quality and determine whether the air is healthy for outdoor activity, and so on,” Masri explained.
The World Air Quality Index Project’s interactive map also shows levels of PM2.5 and ozone in towns and cities across the globe.
But technological developments mean you can check air quality from your backyard using small air sensors, typically costing $100–300.
For instance, Masri noted that PurpleAir sells “low cost air quality sensors which provide real-time PM2.5 data throughout the U.S. and abroad.”
“The AtmoTube company also sells small mobile sensors at a similar cost. Both devices have been validated for their accuracy in monitoring PM2.5,” Masri added.
Although many pollutants are in the air (including “natural” ones, such as pollen), two types have the greatest effects on health.
Fine particulate matter
Microscopic PM2.5 particles are so small they measure about 1/40th of the width of a human hair, Masri told Healthline.
Various sources release chemicals and toxins that contribute to PM2.5, Dickerson said. These particularly include those which involve the burning of fossil fuels, such as:
- cars and trucks
- industries (i.e., electricity, steel production, manufacturing)
Some forms of PM2.5 are more harmful than others, Vanos noted.
“PM2.5 from wildfires are of greatest concern [to health] due to a more toxic composition (which depends on what is being burned in addition to trees; e.g., houses, cars) than other types of PM2.5,” she told Healthline.
You’ve likely heard of the “good” ozone layer, which sits in the Earth’s stratosphere and helps block the sun’s harmful UV rays.
However, ozone gases also float at ground level — and Masri noted these are known as a “secondary pollutant.” This is because they aren’t emitted directly from sources such as cars.
Instead, they form “after vehicle emissions linger in the atmosphere for a while and react with sunlight and other pollution (volatile organic compounds, also known as VOCs),” he said.
Wildfires in recent years have been a prime example of how climate change contributes to poor air quality.
Driven by rising global temperatures and drier landscapes, the number of wildfires is estimated to double by the end of the century.
A 2023 study links wildfire smoke to an increased risk of all-cause, non-accidental, and neoplasm (abnormal excess tissue growth) mortalities.
Donahue explained it’s the dense volume of PM2.5 that causes the reddish smoke haze following wildfires.
But it isn’t the only climate change factor exacerbating air pollution.
Burning fossil fuels releases carbon dioxide and acts as a precursor for PM2.5 and ozone, Donahue said.
Ozone pollution is also known to worsen in high temperatures. This is because the chemical reaction in ozone generation occurs when it’s very sunny, through a process called photochemistry, explained Dickerson.
“When it’s very hot, [the air is] stagnant, and winds are very weak,” he continued, “and that exacerbates the problem.”
These weather conditions also cause high pressure, said Dickerson, which means air cannot move vertically as much, preventing pollution from “escaping” upward. Furthermore, hot weather causes some chemical reactions in pollutant creation to occur much faster.
Finally, as temperatures rise, so does electricity consumption — thanks to reliance on cooling systems. This involves even more burning of fossil fuels, which “contributes to higher sulfur and nitrogen pollution of the atmosphere, [and] higher PM2.5 pollution,” Masri shared.
While a solution to our growing air pollution problem has yet to be determined, the future isn’t all doom and gloom.
North America and Europe have made “huge progress” in reducing air pollution over the past couple of decades, said Dickerson — with EPA data revealing that PM2.5 levels decreased 42% between 2000 and 2022.
Ozone levels have also dropped, although not quite to the same degree: decreasing 29% between 1980 and the present day.
“Other pollutants, such as carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead, are much less of a problem than they once were over,” Donahue noted. “This is a huge success story of clean air regulation.”
He added that reformulations of fuel and catalytic converters in vehicles have also led to notable reductions in harmful auto emissions.
That said, it’s no excuse for complacency. The burning of fossil fuels remains high, accounting for 80% of the world’s energy supply.
Plus, noted Dickerson, “we’ve not made much progress on greenhouse gases” — the key driver behind climate change.
“As the climate changes, air quality is going to get worse,” he said. “They’re very tightly linked.”