Outdoor air quality has improved since the 1990s, but many challenges remain in protecting Americans from air quality problems. Ground-level ozone, the main part of smog, and particle pollution are just two of the many threats to air quality and public health in the United States.
Learn how ground-level ozone can harm your health — and what you can do to protect yourself.
Information about potential health effects caused by volcanic ash and gases, and precautions you can take.
Find information on public health issues related to air quality, including asthma, heart disease and stroke, and more.