Volatile Organic Compound Exemptions
What are VOC?
Volatile Organic Compounds (VOC) react with nitrogen oxides on hot summer days to form ozone (smog). Car exhaust, gasoline-powered lawn and garden equipment, gasoline dispensing stations, industrial coating operations, printing shops, paints, household chemicals - are some of the sources of VOC. There are thousands of individual chemical species of VOC that can react to form ozone. The regulatory definition of VOC, including those compounds determined to have negligible photochemical reactivity, has been published at 40 CFR 51.100(s).
What are VOC Exemptions?
Some VOC react slowly and changes in their emissions have limited effects on local or regional ozone pollution episodes. Those VOC, determined to have low photochemical reactivity by approved test methods, may be excluded from the VOC definition for certain regulatory purposes. These determinations are made by regulation and are commonly referred to as VOC Exemptions. Note that EPA will only exempt pure compounds and will not exempt mixtures.
The policy of excluding negligibly reactive compounds from the regulatory definition of VOC was first laid out in the “Recommended Policy on Control of Volatile Organic Compounds” (42 FR 35314, July 8, 1977) and was supplemented subsequently with the “Interim Guidance on Control of Volatile Organic Compounds in Ozone State Implementation Plans.” Exemption of a compound from the EPA’s VOC definition in 40 CFR 51.100(s) does not exempt it from other regulation, such as due to its toxicity, greenhouse gas formation potential or other properties.