The 1970 Clean Air Act is the backbone of U.S. air-pollutant control policy. Passed in 1970 during the Nixon administration, the Clean Air Act gave teeth to previous pollution control acts by authorizing the newly created Environmental Protection Agency to set National Ambient Air Quality Standards, identify harmful pollutants, and limit their levels in the air. The agency identifies six ‘criteria’ pollutants: carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, particulate matter, and lead. States are required to develop state implementation plans (SIPs) to administer pollution controls tailored to industrial and mobile sources specific to each area. The act also called for the phasing out of leaded gasoline by the 1980s, which was, according to the watchdog group Environmental Defense, “one of the single most important and successful environmental health initiatives of the last century.” The act gave citizens the right to take legal action against those who violate emissions standards or against the EPA for failing to enforce its own rules.
A 1977 amendment included the New Source Review, which requires new industrial facilities and power plants to meet EPA emissions requirements. Older facilities were not required to meet new Clean Air Act standards. If they were upgraded, however, they would be required to install pollution-control measures to meet requirements.
The effect has been “broadly and hugely positive,” says Judi Greenwald of the Pew Center on Global Climate Change. A 1997 EPA self-assessment saw massive reductions in the criteria pollutants and a nearly 100 percent reduction in lead emissions between 1970 and 1990. The EPA estimates the net economic benefit from reduced medical care costs, improvements in visibility, and reduced damage to agriculture is $22.2 trillion.
1990 Clean Air Act (US)
The 1990 Clean Air Act amendments addressed urban air pollution, toxic air emissions, and acid rain. To combat urban smog, the amendments called on the EPA to tighten pollution standards on cars and trucks and mandated the use of cleaner, “reformulated” gasoline. The act also mandated the use of “Maximum Achievable Control Technology” to reduce emission of additional substances harmful to human health but not covered by the 1970 act. An April 2007 Supreme Court decision may expand the Clean Air Act’s purview, as the court ruled in a 5-4 decision that the EPA has the authority to regulate heat-trapping gases in automobile emissions.
To combat acid rain, the law limits the production of sulfur dioxide by power plants in a cap-and-trade system. Limits are set, and each source is allocated pollution allowances, which polluters can buy or sell according to their own economic needs. They can receive bonus allowances for achieving lower levels. Alan Krupnick, director of Resources for the Future, an environmental analysis think tank, says that the sulfur dioxide allowance trading program has “led the way to a revolution in thinking about the use of market-based instruments for pollution control.” A similar cap-and-trade program for nitrogen oxide—a pollutant that contributes to smog—functions in the Northeast and Mid-Atlantic states.
A 2005 National Acid Precipitation Assessment Program Report found that the 1990 amendments significantly decreased emissions that cause acid rain, a result the EPA credits to the cap-and-trade program. Overall, benefits of the 1990 amendments exceeded implementation costs by a factor of four, with a maximum estimate of $1.4 trillion, according to an EPA assessment. The act also mandated a phase-out of substances that damage the ozone layer, to comply with the stipulations of the Montreal Protocol.
