is not emitted directly into the air, but is created by chemical reactions. Volatile organic compounds (VOCs) along with nitrogen oxides (NOx) in the presence of sunlight form ground-level ozone. You can view this process at EPA’s AIRNOW video
. Once emitted, VOCs and NOx may be transported beyond state boundaries and undergo complex chemical reactions along the way, including ozone and fine particulate formation.
Clean Air Act Provisions on Interstate Air Pollution Transport
The Clean Air Act in Section 110, known as the “good neighbor” provision is designed to prevent one state significantly contributing to a National Ambient Air Quality Standards
(NAAQs) violation in another state. Section 176A authorizes the EPA administrator to establish, by rule, a transport region for a pollutant where the EPA administrator believes that the interstate transport of such air pollutants from one or more states contributes significantly to a violation of a NAAQS
in one or more other states. In the 1990 Clean Air Act Amendments, Congress established a specific 12-state transport region for ozone (OTR), extending from Maine south to northern Virginia, pursuant to Section 184 of the act. Section 176A enables EPA administrator to add a state to the transport region or a state may be added by a petition to the administrator. A petition or request under Section 176A must be approved or disapproved by the EPA within 18 months of receipt. In addition to the transport region, the act also authorizes the establishment of a transport commission. The Ozone Transport Commission (OTC) is a multi-state organization responsible for advising the EPA on transport issues and developing and implementing solutions to address ground-level ozone problems.
Key Ozone Transport Information