Air Quality - Lesson 6 : What Has Been Done About Air Pollution?

Most of the air pollution laws in the United States have been enacted within the past 100 years. In the United States, smoke abatement ordinances, which originally prohibited emissions of dense black smoke, began to appear during the late 1800s in urban centers such as St. Louis, Pittsburgh, and Chicago. The original federal Clean Air Act (CAA) was enacted in 1963 with amendments in 1970 that set up an air pollution program at the national level. The federal Clean Air Act Amendments of 1990 contain many programs to address a number of air pollution problems including air toxics, acid rain, and stratospheric ozone depletion. Michigan’s first major Air Pollution Act was enacted in 1965. The current Michigan Air Pollution Control Rules have been adopted pursuant to Part 55, Air Pollution Control, of the Natural Resources and Environmental Protection Act, 1994 PA451.

The federal Clean Air Act sets standards for common air pollutants that can injure health, harm the environment, and cause property damage. EPA calls these pollutants criteria air pollutants because the agency has based regulation standards on healthbased criteria (science-based guidelines). One set of limits (primary standard) protects health; another set of limits (secondary standard) is intended to prevent environmental and property damage. A geographic area that meets or does better than the primary standard is called an attainment area; areas that do not meet the primary standard are called nonattainment areas.

Although the Clean Air Act (CAA) is a federal law setting limits on the amount of pollutants that can be in the air anywhere in the country, individual states do much of the work to carry out the Act. States have to develop state implementation plans (SIPs) that explain how each state will do its job under the CAA. A state implementation plan is a collection of the regulations a state will use to clean up polluted areas.

Michigan began issuing state air permits to facilities in 1967. The 1990 Clean Air Act Amendments put into place a federal permit program, known as Title V (“five”) or a renewable operating permit, for larger sources that release pollutants into the air. The federal permit includes information on which pollutants are being released, how much may be released, and what kinds of steps the source’s owner or operator is taking to reduce and monitor pollution. Businesses seeking permits pay permit fees much like car owners pay for car registrations. The money from the fees helps to pay for state air pollution control activities. An inventory of air emissions is required yearly for some facilities. Inspectors from the Michigan Department of Environmental Quality’s (MDEQ) district offices determine whether a facility is in compliance with air quality regulations.

There have been dramatic improvements in some pollutant levels since the inception of the “command and control” strategies in federal and state regulations. Command and control means there are specific requirements prescribing how to comply with specific standards defining acceptable levels of pollution. Pollution control devices are installed to meet standards. Examples are baghouse filters and electrostatic precipitators to remove particulates and scrubbers for removing sulfur dioxide. Also, many companies have undertaken pollution prevention programs to reduce their air emissions.

The 1990 Clean Air Act Amendments have many features designed to clean up air pollution as efficiently and inexpensively as possible, letting businesses make choices on the best way to reach pollution cleanup goals. These new flexible programs are called market or market-based approaches (“cap and trade”). For instance, the Acid Rain Program caps the amount of sulfur dioxide emissions for utilities, but it offers them choices as to how they reach their pollution reduction goals. The acid rain program includes pollution allowances that can be traded, bought, or sold. Another approach is to allow offsets. An increase in a criteria air pollutant can be offset with a reduction of the pollutant from some other stack at the same plant or another plant owned by the same company or some other company in the nonattainment area. Since total pollution will continue to go down, trading offsets among companies is allowed.

The MDEQ and EPA track air quality based on actual measurements of pollutant concentrations through a network of monitoring stations. Michigan began sampling contaminants in the atmosphere in 1956. Trends are derived by averaging direct measurements from these monitoring stations on a yearly basis. Also, the EPA and MDEQ estimate emissions of the 6 principal air pollutants and the 188 toxic air pollutants regulated under the Clean Air Act. These estimates are based on many factors, including actual monitored readings, levels of industrial activity, fuel consumption, vehicle miles traveled, and other activities that cause pollution. Both the EPA and MDEQ periodically report the levels of air pollutants in publications such as the National Air Quality Status and Trends Report and the MDEQ Annual Air Quality Report.

Currently, all areas of Michigan are in compliance with National Ambient Air Quality Standards (NAAQS) for lead, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Although Michigan met earlier particle and ozone standards, the standards became more stringent as of 1998. In 2004, many counties in Michigan’s Lower Peninsula were designated by the EPA to be in nonattainment for the new ozone standard. In that same year, the Detroit area was designated to be in nonattainment for particle pollution, specifically the fine particles (PM2.5).

We can anticipate even more improvements in air quality. Rules continue to be developed for a variety of industrial categories emitting air toxics. In 2004, as part of its Clean Diesel Programs, the EPA finalized a comprehensive rule to reduce emissions from non-road diesel engines by integrating engine and fuel controls as a system to gain the greatest emission reductions. The new engine standards will reduce particle pollution and NOX emissions by 90%. In 2005, the EPA issued the Clean Air Interstate Rule (CAIR), a rule that will achieve the largest reduction in air pollution in more than a decade. CAIR will permanently cap emissions of sulfur dioxide (SO2) and nitrogen oxides (NOX) in the eastern United States. When fully implemented, CAIR will reduce SO2 emissions in these states by over 70% and NOX emissions by over 60% from 2003 levels. This will result in a savings of $85 to $100 billion in health benefits and nearly $2 billion in visibility benefits per year by 2015 and will substantially reduce premature mortality in the eastern United States. Actions by EPA and MDEQ as well as the federal Executive and Judicial branches of government are part of the ever changing landscape of air quality regulations. EPA and MDEQ have updates on their air quality web pages that are useful for this lesson.


Michigan Department of Environmental Quality.

Air Quality Division. Michigan’s Air. Retrieved June 20, 2005,


U.S. Environmental Protection Agency. Office of Air

and Radiation. Retrieved June 20, 2005, from

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