Air Quality Index: a Guide to Air Quality and Your Health

"The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect public health ..."
Air Quality Index

EPA Proposes Clean Air Standards for Harmful Soot

"In response to a court order, the U.S. Environmental Protection Agency (EPA) today proposed updates to its national air quality standards for harmful fine particle pollution, including soot (known as PM2.5). These microscopic particles can penetrate deep into the lungs and have been linked to a wide range of serious health effects, including premature death, heart attacks, and strokes, as well as acute bronchitis and aggravated asthma among children. A federal court ruling required EPA to update the standard based on best available science. Today’s proposal, which meets that requirement, builds on smart steps already taken by the EPA to slash dangerous pollution in communities across the country. Thanks to these steps, 99 percent of U.S. counties are projected to meet the proposed standard without any additional action..."

The Clean Air Act Where You Live

"This Administration has taken a series of reasonable, common-sense steps under the Clean Air Act – many of which are decades over due and issued in response to court orders – to reduce emissions of mercury, acid gas, particulate matter, arsenic and other harmful chemicals from some of the biggest polluters in the nation. Two of these, the Cross State Air Pollution Rule and the proposed Mercury and Air Toxics Standards, will save tens of thousands of lives, prevent hundreds of thousands of asthma and heart attacks and avert millions of missed school and work days – yielding hundreds of billions of dollars in benefits to our communities. The Cross State Air Pollution Rule ensures that hundreds of millions of Americans from the midwest to the East Coast are not forced to breathe air pollution from other states."

EPA Report Underscores Clean Air Act’s Successful Public Health Protections/Landmark law saved 160,000 lives in 2010 alone
"A report released today by the U.S. Environmental Protection Agency (EPA) estimates that the benefits of reducing fine particle and ground level ozone pollution under the 1990 Clean Air Act amendments will reach approximately $2 trillion in 2020 while saving 230,000 people from early death in that year alone. The report studied the effects of the Clean Air Act updates on the economy, public health and the environment between 1990 and 2020.

The EPA report received extensive review and input from the Council on Clean Air Compliance Analysis, an independent panel of distinguished economists, scientists and public health experts established by Congress in 1991..."