Toxic air pollutants

Although considerable federal legislation dealing with air pollution has been enacted since the 1950s, the basic statutory framework now in effect was established by the Clean Air Act of 1970 amended in 1974 to deal with energy-related issues amended in 1977, when a number of amendments containing particularly important provisions associated with the approval of new industrial plants were adopted and amended in 1990 to address toxic air pollutants and ozone nonattainment areas. 

The 1990 CAAA introduced a new level of control for hazardous (toxic) air pollutants (HAPs). As a result, EPA has identified 189 HAPs for regulation. Rather than rely upon ambient air qnahty standards to set acceptable exposures to HAPs, the CAAA requires that EPA promulgate through the end of the decade Maximum Achievable Control Technology (MACT) standards for controlling HAPs emitted from specified industries. These standards are based on the level of control estabhshed by the best performing 12 percent of industries in each of the categories identified by EPA. 

Toxic air pollutants are pollutants which are hazardous to human health or the environment but which are not specifically regulated by the CAA. These pollutants are typically carcinogens, mutagens, and teratogens. The CAAA of 1977 failed to result in substantial reductions in the emissions of these harmful substances. 

The toxic air pollution problem is widespread. Information generated from the Superfund "Right to Know" rule From the Superfund Authorization and Recovery Act (SARA Section 313) indicates that more than 2.7 billion pounds of toxic air pollutants are emitted annually in the United States. EPA studies indicate that exposure to such quantities of air toxics may result in 1000 to 3000 cancer deaths each year. 

The CAAA90 offers a comprehensive plan for achieving significant reductions in emissions of hazardous air pollutants from major sources. The new law will improve EPA s ability to address this problem effectively and it will accelerate progress in controlling major toxic air pollutants. 

The law includes a list of 189 toxic air pollutants of which emissions must be reduced. The list of source categories includes (1) major sources emitting 10 tons/year of any one, or 25 tons/year of any combination of those pollutants and (2) area sources (smaller sources, such as dry cleaners). 

EPA, 1992, Work Book of Screening Techniques for Assessing Impacts of Toxic Air Pollutants. EPA-454/R-92-024, December. 

Criteria air pollutants Excluding carcinogenic particles and VOC s (included under luizardous/ toxic air pollutants) ranked low because reittainiitg criteria pollutaitts Itave not been shown to be carcinogens. 

Although the petrochemical and metals industries were the primai y focus of the toxic air pollutants legislation, approximately forty of these substances have been detected in fossil power plant flue gas. Mercury, which is found in trace amounts in fossil fuels such as coal and oil, is liberated during the combustion process and these emissions may be regulated in the future. EPA issued an Information Collection Request (ICR) that required all coal-fired plants to analyze their feed coal for mercury and chlorine. Since these data will be used in making a regulatory decision on mercury near the end ot the year 2000, it is critical that the power industry provide the most accurate data possible. 

Benzene is a known carcinogen. The U.S. Environmental Protection Agency (EPA) has identified benzene as a toxic air pollutant (TAP). Benzene is present in automotive evaporation, refueling vapors, and exhaust. 

The certification of fuels Each refiner, blender, or importer of gasoline must ensure that per-gallon emissions levels of VOCs, NOv, CO, and toxic air pollutants do not exceed the gasoline sold in 1990. 

D.T. Williams et al, Evaluation of Second Derivative Spectroscopy For Monitoring Toxic Air Pollutants , SAM TR-74-19, Proj AF-7164, Contract F 41609-73-C-0011 (1974)... 

Klaassen CD. 1985. Nonmetallic environmental toxicants Air pollutants, solvents, and vapors, and pesticides. In Gilman AG, Goodman LS, Rail TW, et al., eds. Goodman and Gilman s The pharmacological basis of therapeutics. 7th ed. New York, NY MacMillan Publishing Co., 1628-1637. 

Wallace LA, Pellizzari ED, Hartwell TD, et al. 1985. Personal exposures, indoor-outdoor relationships, and breath levels of toxic air pollutants measured for 355 persons in New Jersey. Atmos Environ 19 1651-1661. 

Highly toxic air pollutants fall under Section 112 of the Clean Air Act. Unlike criteria pollutants, these hazardous air pollutants must be controlled to protect the public health with an "ample margin of safety." Implied in this language is the belief in a discrete threshold of exposure below which no effects occur and from which a safety margin can be measured. Subsequent interpretations, however, indicated clearly that Congress did not equate safeguarding the public health with complete risk elimination. 

Pratt GC, Gerbec PE, Livingston SK, Oliaei F, Bollweg GL, Paterson S, Mackay D (1993) An indexing system for comparing toxic air pollutants based upon their potential environmental... 

State of Kentucky. 1986. New or modified sources emitting toxic air pollutants. Natural Resources and Environmental Protection Cabinet, Department for Environmental Protection, Division of Air Pollution (Proposed Regulation). 401 KAR 63 022. 

LA Air Qual. Div. 1998. Louisiana toxic air pollutant ambient air standards. Louisiana Air Quality Division, Department of Environmental Quality. Chapter 51, Subchapter A. 

NH Air Res. Div. 1998. Toxic air pollutants With toxicity classifications and ambient air limits. New Hampshre Air Resources Division, State Department of Environmental Services. NH Code Admin. R. Ann. Env-A 1300,1400. 

SC Bureau Air Qual. 1998. Toxic air pollutants with maximum allowable concentrations. South Carolina Bureau of Air Quality, Department of Health and Environmental Control. 24A SC Code Ann. Regs. 61-62.5 Standard 8. 

WA Air Qual. Program. 1998. Toxic air pollutants and acceptable source impact levels. Washington Air Quality Program, Department of Ecology. Wash Admin Code Section 173-460. 

Petroleum refineries are a somce of hazardous and toxic air pollutants, such as BTEX compounds (benzene, toluene, ethylbenzene, and xylene). They are also a major source of criteria air pollutants particulate matter (PM), nitrogen oxides (NO t), carbon monoxide (CO), hydrogen sulfide (H2S), and sulfur oxides (SO ). 

Louisiana Toxic air pollutant Minimum emission rate 25 pounds/year BNA 2001... 

New Mexico Toxic air pollutant OEL Emissions 0.3 mg/m 0.02 pounds/hour BNA 2001... 

Permutt TJ, Moezzi M, Hudischewskyj AB, et al. 1987. Statistical analysis of concentrations of toxic air pollutants in California and Louisiana. Proceedings of the APCA Annual Meeting 80 87/66.1. 

Lioy PJ, Daisey JM, Morandi MT, et al. 1987. The airborne toxic element and organic substances (ATEOS) study design. In Lioy PJ, Daisey JM eds. Toxic air pollutants A comprehensive study of non-criteria air pollutants. Chelsea, MI Lewis Publishers, Inc., 3-42. 

---