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Panel: Steve Risotto
Media: Sarah Scruggs

Regulation to Control Ground Level Ozone

Ground-level ozone is the main component of urban smog. It is formed by the photochemical reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the atmosphere. In order to reduce ozone levels, the Clean Air Act regulates man-made emissions of both VOCs and NOx.  There are several significant sources of VOC emissions, including natural or “biogenic” sources such as trees and vegetation, and man-made sources such as vehicle emissions, petroleum refining and distribution, and combustion sources. Significant VOC emissions also come from the use of organic solvents, most of which are classified as VOCs.

Areas of the country that do not meet national standards for ground-level ozone are referred to as “ozone nonattainment areas.” Under the Clean Air Act, these areas generally are required to reduce VOC emissions within their boundaries (not including vehicle emissions) by 3 percent each year until the national standard is met.

Emissions of VOCs, in and of themselves, do not necessarily give rise to health or environmental concerns. In many areas, however, they react with oxides of nitrogen (NOx) in the presence of heat and sunlight to form ground-level ozone – the primary component of “smog.” For that reason, they are regulated as “ozone precursors” under the federal Clean Air Act and similar state laws.

In order to reduce ozone levels, federal and state agencies have developed regulations to reduce VOC emissions from a variety of sources, including products that contain solvents. In some cases, for major coating operations, for example, these regulations require the installation of a control device such as an incinerator or a solvent recovery system. In other cases, they limit the amount of solvent that can be used in products but do not prohibit their use.

In most cases, a specific set of regulations has been or will be developed for each different industry or type of emission source. For industries that use solvents in coatings, the regulations often set emission standards based on the VOC content of these coatings. Typically, the State or local agency will issue regulations limiting VOC emissions – often based on EPA guidance. In some cases, however, the Clean Air Act authorizes EPA to issue regulations. For example, EPA has promulgated regulations limiting the VOC content of architectural coatings, automobile refinish coatings and certain household consumer products such as cleaning products, personal care products, and insecticides. As discussed later, end users have several options for meeting such a standard.

Some specific examples of federal VOC guidance and regulations include the following:

  • Alternative Control Techniques Documents: These EPA guidance documents provide specific recommendations for State and local agencies to incorporate into their rules for controlling VOC emissions. Solvent-related documents include: 
    • Industrial Cleaning Solvents (1994) (EPA-453-R-94-015)
    • Auto Refinishing (1994) (EPA-453/R-94-031)
    • Offset Lithography (1994) (PB95-201018)
    • Plastic Parts (1994) (EPA-453/R-94-017)
    • Shipbuilding (1994) (EPA-453/R-94-032)

  • Beyond VOC RACT CTG Requirements (1995) (EPA-453/R-95-010): This EPA guidance document identifies State and local requirements that are more stringent than EPA’s RACT (reasonably available control technology) “Control Technique Guidelines,” or CTGs. CTGs are used by State and local governments to identify requirements for VOC reductions. Source categories addressed in this guidance include: solvent metal cleaning, surface coating of automobiles and light-duty trucks, graphic arts, and surface coating of cans, fabrics, large appliances, metal coils, metal furniture, magnet wire, miscellaneous metals parts, flat wood paneling and paper.
  • National Volatile Organic Compound Emission Standards for Automobile Refinish Coatings. 40 C.F.R. Part 59, Subpart B (§§59.100 – 59.111)
  • National Volatile Organic Compound Emission Standards for Consumer Products. 40 C.F.R. Part 59, Subpart C (§§59.201 – 59.214).
  • National Volatile Organic Compound Emission Standards for Architectural Coatings. 40 C.F.R. Part 59, Subpart D (§§59.400 – 59.413).
Other guidance may be available, and some of these guidance documents and regulations may be outdated or supplanted. Check with EPA for the most up-to-date guidance and regulations.


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