Climate change is expected to result in greater risks of unhealthy outdoor air. Great progress has been made in cleaning our air, but climate change complicates efforts to attain and/or maintain safe air quality.
Ground-level ozone and particulate matter are of particular concern. Both pollutants are the result of emissions from diverse sources, travel long distances and travel across state lines. And both are likely to worsen with the changing climate. Both can have significant health impacts.
Climate change is expected to result in higher temperatures, which contribute to increased ground level ozone, both more days with elevated levels and increases in ozone levels on specific days. Metropolitan and suburban areas see some of the higher ozone levels, because the emissions in populous areas are contributors to ozone formation, but because emissions can travel long distances, high ozone levels can occur in remote areas as well.
Particulate matter means tiny particles of pollution, one tenth or less the diameter of a human hair. Longer and more intense droughts and extreme heat events increase the likelihood of wildfires, which release significant amounts of particulate matter into the air and threaten public health. As the climate changes, wildfires are expected to increase in many parts of the country. Higher temperatures and drought can also lead to drier conditions and more dust.