How Does the Establishment of an Ozone Transport Region Affect I/M?
Emissions from cars and trucks are a major contributor to ozone nonattainment problems in our cities. For that reason, additional measures are taken in an Ozone Transport Region to bring these emissions under control. In an Ozone Transport Region, the Clean Air Act requires that enhanced I/M be implemented in all Metropolitan Statistical Areas with a population of 100,000 or more regardless of attainment status. This is because hydrocarbons and oxides of nitrogen emitted by vehicles in areas where ozone pollution is not a problem can be transported on the wind to nearby urbanized areas and contribute to ozone nonattainment there.
