EPA brochure describing the health and environmental effects of haze.
Report by William Malm, National Park Service and Colorodo State Institute for Research on the Atmosphere
Visibility is improving, but we can do more to protect America’s magnificent views and scenic vistas from pollution.
In 1999, the U.S. Environmental Protection Agency announced a major effort to improve air quality in national parks and wilderness areas.
The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants (also known as “criteria air pollutants”).
Ozone can be “good” or “bad” for health and the environment depending on where it’s found in the atmosphere.
National Ambient Air Quality Standards (NAAQS) for ground-level ozone, or ozone pollution, specify a maximum allowed measurement for ozone (O3) to be present in outdoor air.
The Clean Air Act requires EPA to designate areas in the United States after the agency sets a new National Ambient Air Quality Standard (NAAQS) or revises an existing standard
PM stands for particulate matter (also called particle pollution): the term for a mixture of solid particles and liquid droplets found in the air.
National Ambient Air Quality Standards (NAAQS) for PM pollution specify a maximum amount of PM to be present in outdoor air.
How do we know if an area is not meeting particulate matter (PM) standards?
CO is a colorless, odorless gas that can be harmful when inhaled in large amounts.