Climate Change and Air Quality: What You Need to Know

Since the creation of the Clean Air Act of 1963, the U.S. has made great strides in reducing human-made air pollution. While our current air quality is much better than it was in the early 20th century, there’s growing evidence that the effects of climate change have started reversing some of that progress. In many parts of the country, climate-driven weather patterns, including heat waves, droughts, and wildfires, often increase outdoor air pollution to unsafe levels. For example, between 2000 and 2021, the western U.S. saw a 477% increase in poor air quality days, mostly due to particle pollution from wildfire smoke.

Around the world, air pollution plays a part in over four million deaths each year — a number that’s only expected to increase as the climate continues changing. Clean air is essential to human health, and increased exposure to air pollution is likely to lead to increased hospitalizations, respiratory illnesses, and cardiovascular conditions over the coming decades. As we explore the impact of climate change on air quality, it’s easier than ever to recognize the importance of protecting the air we breathe.

Air pollution and climate change

Climate change and air quality are inextricably linked — you just can't separate one from the other — and different types of air pollution impact our climate in different ways. For example, greenhouse gases like carbon dioxide (CO2) and ozone (O3) trap heat in the atmosphere and raise the planet's average temperature. Black carbon, a type of particle pollution created by wildfires and other forms of combustion, also has a warming effect on the environment. On the other hand, sulfur particles, a pollutant made by burning fossil fuels like gasoline, have a cooling effect on the atmosphere. Together, all the effects of different types of pollution lead to long-term disruptions in Earth's climate and weather patterns.

Climate change and air quality

Climate change affects air quality by disrupting weather patterns, including precipitation and temperature, in ways that increase airborne pollutants. For example, higher temperatures can increase ground-level ozone pollution, and longer spring and summer seasons lead to higher levels of pollen in the air. As droughts become worse and more frequent in some parts of the country, we also see a rise in particle pollution caused by windblown dust and wildfire smoke. 

Climate-driven changes to air quality can increase pollution exposure and impact public health, worsening respiratory and heart conditions and leading to increased hospital visits and premature deaths.

Ground-level ozone

Ground-level ozone (one of the main pollutants in smog) forms when sunlight meets smoky emissions from vehicle exhausts and other sources. Hot weather and stagnant air create the perfect conditions for ozone formation, and thanks to climate change, those conditions occur more and more often. The top 10 warmest years in recorded history have all happened in the past decade, and 2023 was the world’s warmest year on record. Temperatures are expected to keep rising, and large parts of the U.S. are likely to see increased ozone levels, even with current efforts to reduce ozone pollution. Exposure to ground-level ozone can cause coughing, trouble breathing, increased asthma attacks, and worsened lung diseases such as asthma, emphysema, and chronic bronchitis.

Wildfires

Wildfire smoke is the biggest driver of air pollution in the western U.S., and a new study in the Lancet Planetary Health Journal estimates that it’s caused an increase of at least 670 premature deaths each year since 2000. As climate change drives hotter temperatures and more severe droughts, wildfire season stretches longer and fires grow larger and more frequent. Particle pollution from wildfire smoke has increased so much that it’s actually started to counteract long-term air quality improvements from cutting down human-made pollution emissions. 

In 2020, wildfires burned more than 10 million acres of land across the U.S., setting a new record. Though the areas near fire sites see the most significant impact on air quality, places hundreds or thousands of miles away may still see unhealthy levels of particle pollution from wildfire smoke. Smoke exposure can lead to coughing, asthma flare-ups, and increased symptoms from respiratory illness, including chronic obstructive pulmonary disease (COPD) and bronchitis.

Extreme weather events

Climate-driven disruptions to weather patterns also increase the risk of extreme weather events, such as flooding and dust storms. For example, rising water levels, more frequent hurricanes and heavy storms, and increased snowmelt all increase flood risk in different parts of the country. Homes with water damage from floods or other weather events often see mold growth, bacteria, and other kinds of indoor air pollution.

In other parts of the country, long-term droughts and higher temperatures dry out the soil, increasing particle pollution from windblown dust. Climate change is expected to drive even greater increases in floods, hurricanes, dust storms, heat waves, and other extreme weather events that can affect air quality.

Airborne allergens

People with allergies and asthma will probably notice another effect of climate change — longer, more severe allergy seasons. With temperatures and carbon dioxide levels on the rise, plants can produce more pollen throughout the year. Increasing exposure to airborne ragweed pollen and other allergens can worsen allergic reactions and lead to more allergy-related illnesses, including asthma and hay fever. Exposure to other types of air pollution on top of increased pollen levels can make respiratory symptoms even worse.

Indoor air quality

Any changes in outdoor air quality — like higher levels of ozone, particulate matter, pollen, and other pollutants — can impact indoor air pollution levels too. Climate-related increases in severe droughts and storms can also create conditions that produce other indoor pollutants, including mold, dust mites, and bacteria. Exposure to indoor air pollution is linked to short-term symptoms like headaches and eye, nose, and throat irritation, as well as long-term effects, including heart and respiratory diseases and cancer.

Preparing for poor air quality

Though individuals, companies, and governments continue fighting to slow climate change, increased outdoor air pollution is our current reality. As air quality gets worse, it’s even more important to learn how to protect yourself from unhealthy pollutants in the air. You can use the EPA’s Air Quality Index (Airnow.gov) to find air quality data for your area. Monitoring your local air quality will help you choose when and how to spend time outdoors without exposing yourself to unhealthy air pollution. (The EPA’s Air Quality Guide for Particle Pollution offers more detailed recommendations on outdoor activities for different pollution levels.)