National Air Quality Events and Trends
The federal government's involvement in air pollution control began in 1955 with the passage of Public Law 159. Congress adopted this measure in response to deteriorating air quality in the nation's industrial centers during the 1940s and 1950s. Eight years later, the passage of the Clean Air Act was the first bill that gave the federal government authority to get involved in solving the nation's pollution problems.
For the past 35 years, Congress has continued to expand and strengthen its role in promoting air quality management through a series of amendments designed to protect public and environmental health. Today, federal, state, and local governments continue to promote improved air quality in communities across the country.
photo courtesy of Montana Historical Society
Donora's Deadly Smog
In 1948, in a mill town 28 miles south of Pittsburgh, Pennsylvania, an air pollution disaster occurred that shocked the nation and, ultimately, gave birth to the Clean Air Act of 1970.
Donora, Pennsylvania, was home to the American Steel and Wire Co. zinc and iron works, where a large number of local residents were employed. On October 28, 1948, an inversion layer trapped sulfur dioxide emissions from the zinc works, exposing residents to a deadly cloud of sulfuric acid. Within a day, some elderly people were gasping for breath. One day later, nauseated patients crowded the area's two hospitals. By the third day, people in Donora were dying—the first known deaths from air pollution in America.
All told, 20 Donorans died before the acrid smog cleared, and 6,000 residents—nearly half of Donora's population—were temporarily sickened. The tragedy in this tiny Monongahela River town became a national symbol, often cited as proof that pollution can kill.
Within 20 years, American Steel and Wire Co. closed. The Donora tragedy (compounded by similar occurrences elsewhere in the country) prompted federal legislation to address air pollution.
Timeline of Significant National Air Quality Legislation and Events
1955
Congress adopts Public Law 159, which authorizes federal research on the nature
and extent of the country's air pollution problems and develops air quality criteria.
1962
The publication of Silent Spring by Rachel Carson in 1962 focuses public attention on the
increasing use of DDT and other pesticides, and the impact of these chemicals on wildlife.
It is credited by many for creating public interest and enthusiasm in environmental issues
across the United States.
1963
Congress passes the Clean Air Act of
1963 to provide grants to state and local agencies for regional
pollution control programs. The Clean Air Act also gives the
federal government the authority to mediate interstate pollution
problems.
1965
Congress passes the Motor Vehicle Air Pollution Control Act
stating that national standards should be set for automobile exhaust.
1967
Congress passes the Air Quality Act, expanding and strengthening federal authority over
interstate pollution issues.
1970
Clean Air Act Amendments give EPA the authority to develop the National Ambient Air Quality
Standards (NAAQS) for airborne pollutants that have harmful effects on public health.
These amendments require states to develop State Implementation Plans (SIPs) to reach these
national standards and maintain good air quality. For the first time, citizens also gain the right
to participate in pollution control through public hearings.
1970
The first Earth Day celebration is held April 22, 1970. Stunning photographs from the
Apollo space missions showing the earth from space and the surface of the moon, plus
heightening awareness of environmental issues, makes the first observance of Earth Day
successful. Newspapers throughout the country publish environmental information, and
campuses and communities sponsor lectures and rallies to raise environmental awareness.
1977
Federal government adopts additional Clean Air Act Amendments to regulate pollutants that
have harmful effects on public and environmental health; ensure compliance with national
and regional air quality standards; and establish special programs for hazardous air
pollutants, visibility in national parks, and other air quality issues.
1980
Mount St. Helens erupts May, 1980 spewing volcanic dust and ash into atmosphere,
depositing ash throughout the western U.S., including Montana. The eruption demonstrates
that naturally caused events outside the state's borders can have a major impact
on air quality within the state.
1984
In 1984 in Bhopal, India, a Union Carbide plant accidentally releases a highly toxic chemical,
methyl isocyanate, into the air. At least two thousand people die as a result of exposure to
the chemical and many more thousands suffer adverse health effects. Soon after this incident, Congress
passes the Emergency Planning and Community Right-to-Know Act (EPCRA) to
require businesses to notify state and local authorities about toxic chemicals stored on site
and released into the air.
1990
Federal government further amends the Clean Air Act, establishing additional programs to
deal with nonattainment areas where the national standards have been exceeded, as well
as vehicles and fuels, air toxics, acid rain, and operating permits for pollution sources.
1991
Congress passes the Intermodal Surface Transportation Efficiency Act (ISTEA).
ISTEA provides funding for the national transportation system including the surface highway system,
interstate system, transit and other transportation programs. ISTEA is a milestone in
transportation planning because of the requirements for planning criteria to include environmental
issues and energy efficiency. The next reauthorization of federal transportation funding, called
TEA-21 or the Transportation Efficiency Act for the 21st Century, passes in June, 1998.
TEA-21 continues the effort to tie transportation planning to air quality planning.
The 1977 Clean Air Act Amendments established several new programs to better protect public and environmental health. These programs addressed three major areas:
- Widespread and Pervasive Pollution Problems
Regulates emissions of criteria pollutants (carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide) and major sources of pollution (power plants, gas stations, smelters, and residential wood burning stoves. - New and Modified Stationary Sources
Requires that new and modified pollution sources control emissions and comply with national and regional air quality standards. - Special Pollution Problems
Establishes national standards for hazardous air pollutants and new programs to protect visibility in national parks.
The 1990 Clean Air Act Amendments established five programs to regulate the sources and consequences of specific air pollutants:
- Title I: Nonattainment Program
Addresses problem pollutants in nonattainment areas, where national standards have been exceeded, and helps revise SIPs to bring these areas back into compliance. - Title II: Mobile Sources, Fuels, and Fuel Additives
Requires automobile manufacturers to reduce tailpipe emissions of hydrocarbons, carbon monoxide, and nitrogen xides. This program also requires reformulated gasoline in areas with excessively high carbon monoxide and ozone levels. - Title III: Air Toxics
Controls hazardous air pollution by targeting the sources of pollution. Title III requires that major pollution sources use the best available control technologies to limit the amount of hazardous pollution released into the air. Title III also requires small businesses to comply with control technology standards for the same purpose. - Title IV: Acid Rain
Controls acid rain by reducing emissions of sulfur dioxide and nitrogen oxides, hich come primarily from power plants and industrial facilities. - Title V: Operating Permit Program
Requires each state to develop an operating permit program that meets all federal regulations and includes emission limits, compliance schedules, and monitoring and reporting requirements. Title V also creates small business assistance programs to help small businesses with pollution prevention and accidental release detection.
