Clean Air Act (1990)

The 1990 Clean Air Act is a piece of Environmental policy of the United States relating to the reduction of smog and air pollution. It follows the Clean Air Act in 1963, the Clean Air Act Amendment in 1966, the Clean Air Act (1970), and the Clean Air Act Amendments in 1977. It was enacted by the 101st United States Congress.

The roles of the federal government and states
Although the 1990 Clean Air Act is a federal law covering the entire country, the states do much of the work to carry out the Act. For example, a state air pollution agency holds a hearing on a permit application by a power plant or chemical plant or fines a company for violating air pollution limits.

Under this law, the United States Environmental Protection Agency sets limits on how much of a pollutant can be in the air anywhere in the United States. States are not allowed to have weaker pollution controls than those set for the whole country.

The law recognizes that states should lead in carrying out the Clean Air Act, because pollution control problems often require special understanding of local industries, geography, housing patterns, etc.

States must develop state implementation plans State Implementation Plan) that explain how each state enforces the Clean Air Act. A state implementation plan is a collection of the regulations a state will use to clean up polluted areas. The states are obligated to notify the public of these plans, through hearings that offer opportunities to comment, in the development of each state implementation plan.

EPA must approve each SIP, and if a SIP isn't acceptable, EPA can take over, enforcing the Clean Air Act in that state.

The United States government, through EPA, assists the states by providing scientific research, expert studies, engineering designs and money to support clean air programs.

Interstate air pollution
Air pollution often travels from its source in one state to another state. In many metropolitan areas, people live in one state and work or shop in another; air pollution from cars and trucks may spread throughout the interstate area. The 1990 Clean Air Act provides for interstate commissions on air pollution control, which are to develop regional strategies for cleaning up air pollution. The 1990 Clean Air Act includes other provisions to reduce interstate air pollution.

The Acid Rain program, created under Title IV of the Act, authorizes emissions trading to reduce the overall cost of controlling emissions of sulfur dioxide.

Leak detection and repair
The Act requires industrial facilities to implement a Leak Detection and Repair (LDAR) program to monitor and audit a facility's fugitive emissions of volatile organic compounds (VOC).

The program is intended to identify and repair components such as valves, pumps, compressors, flanges, connectors and other components that may be leaking. These components are the main source of the fugitive VOC emissions.

Testing is done manually using a portable vapor analyzer that read in parts per million (ppm). Monitoring frequency, and the leak threshold, is determined by various factors such as the type of component being tested and the chemical running through the line. Moving components such as pumps and agitators are monitored more frequently than non-moving components such as flanges and screwed connectors. The regulations require that when a leak is detected the component be repaired within a set amount of days. Most facilities get 5 days for an initial repair attempt with no more than 15 days for a complete repair. Allowances for delaying the repairs beyond the allowed time are made for some components where repairing the component requires shutting process equipment down.