Is Air Pollution Making You Sick?

Air pollution has serious health effects on both the lungs and the cardiovascular system.

Current air pollution levels in the U.S., which are much better than they were before the passage of the Clean Air Act of 1970, are still responsible for more than 88,000 deaths a year, according to Robert Brook, MD, a professor of medicine at the University of Michigan who studies air pollution and health. Some studies even put that number at over 100,000.

There are a number of different types of air pollutants, but experts typically list two major categories: particulate pollution and ozone.

Particulate pollution, which is made up of inhalable microscopic particles emitted from a variety of sources including wildfires and fossil fuels, can peak at any time of the year, depending on weather conditions and how people use energy. 

On the West Coast, these levels often spike over the summer because of wildfires, says John Balmes, MD, a professor of medicine at the University of California, San Francisco, and a spokesperson for the American Lung Association (ALA). Wildfires (this time originating in Canada) have caused the recent record-setting spikes in particulate pollution on the East Coast as well. And it’s early in fire season; air pollution events could continue even after current conditions subside. This is the worst start to the Canadian wildfire season on record. 

Wildfire season is starting earlier and stretching later in some places, but ozone levels always spike during the summer. That’s because ozone is what’s called a “secondarily generated pollutant,” Brook says. When sunlight hits certain pollutants—including those emitted by power plants, industrial boilers, air conditioners, and perhaps most importantly, cars—it creates ozone.

Those pollutants are emitted as people turn on their ACs to try to stay cool and as fumes are pumped out of their vehicle’s exhaust pipes as they drive to work. Then they’re cooked in the hot sun, creating ozone levels that rise throughout the day. Those levels peak at some point in the afternoon and start to fall again after the sun goes down. Long, sunny days will have more ozone. That’s why walking outside or trying to jog on some particularly hot days can feel like you’re trying to breathe through a pillow. 

Ozone and particulate pollution are linked to cardiovascular illness and respiratory problems. Particulate pollution is more directly linked to events like heart attacks, Brook says, while there’s more evidence that ozone affects lung diseases like asthma and chronic obstructive pulmonary disease (COPD). That might help explain why breathing problems are often exacerbated on hot summer days.

Present-day levels of air pollution in the U.S. are half what they were in the 1970s, according to Brook, due to stricter regulations on air pollution. Yet we still have more than twice as many deaths from air pollution (PDF) as we do from traffic accidents.

The number of record-setting air quality alert days for particulate pollution in recent years is part of a worrisome trend, according to the ALA’s State of the Air report. Experts say that factors related to the changing climate as well as the political environment could put our improved air quality in jeopardy.

“That’s why it’s really important that we don’t allow any weakening of air quality [standards],” Brook says. “We’ve made such headway.”

Yet in the past decade, improvements in particulate pollution levels have slowed, according to Cromar, and there’s been little to no change with regard to ozone.

Stricter fuel standards and a large transition away from coal for energy helped us get to where we are now, Cromar says. But further improvements in particulate pollution levels will require even stricter regulations, he says, and reducing ozone levels will require a coordinated effort from local, regional, and federal governments.

Plus, he says, a lot of big cities that already have high ozone levels have growing populations, which means a larger number of people will be exposed to ozone—and contribute to its formation.

At the same time, climate change will lead to more warm, sunny days and more air conditioner use, Balmes says, which will lead to more ozone. Climate change is also linked to greater intensity and frequency of wildfires, according to the Environmental Protection Agency, creating more fine particulate pollutants.

Certain steps can help you reduce your exposure to air pollution, which is particularly important on what’s often referred to as an air quality action or alert day. (Different health departments use different names.) You can always check your local air quality on the EPA’s AirNow website, and your local government may have additional resources or alerts for particular days. 

• Check the forecast. The AirNow site often has recommendations for days with high pollution. When ozone levels are high, it will say that children and people with lung disease should avoid prolonged exertion outdoors. If particulate pollution is high, it may advise people with cardiovascular conditions to reduce outdoor exposure. Sometimes conditions will get bad enough that it will recommend that everyone avoid extended exertion outdoors.
• Don’t skip exercise, but listen to recommendations about avoiding outdoor activity. For a healthy person, the benefits of exercise generally outweigh the risks of air pollution, Brook says. “But it’s silly to exercise in pollutants when you don’t have to,” he adds. Exercise indoors if particulate pollution is high. Because ozone levels fall over the course of the night and won’t rise again until the sun has had time to generate them, outdoor exercisers can minimize ozone’s effects on the lungs by getting out early, Balmes says. The American Lung Association (ALA) also recommends staying away from busy streets while exercising, because pollution levels are much higher near traffic.
• Don’t make the problem worse. The ALA also says that trying to limit your own production of pollutants can help. Don’t smoke indoors, avoid burning wood or trash, carpool or use public transit, and use electric rather than gas-powered appliances when possible.
• Filter the air. If you need to spend time outdoors, Balmes says masks that are specified to filter out PM 2.5 pollutants are effective when particulate pollution is high. Research suggests that wearing a mask can be beneficial for adults and kids, though better-fitting masks designed to filter out tiny particles—like an N-95—are significantly more protective than surgical masks. Indoors, there’s growing evidence that air purifiers may help lessen the effects of air pollution, Balmes says. In one 2018 trial, Brook and colleagues found that using an indoor air purifier with a HEPA filter was associated with a blood pressure reduction roughly equal to switching from a high-salt to a low-salt diet. Consumer Reports tests how well portable air purifiers clean dust, smoke, and pollen from the air; members can check out our ratings here.
• Listen to your lungs. It’s helpful to check out the daily levels of air pollution, but you should also trust your own feelings of discomfort, Cromar says, because everyone reacts slightly differently. When the air is starting to make you feel bad, that’s a sign you should avoid strenuous outdoor activity.