The EPA proposed a rule to lower air pollution from vehicles. The Tier 3 Motor Vehicle Emission and Fuel Standards will reduce the sulfur content of gas to 10 ppm on an annual average basis starting in 2017. The vehicle emission standards will be phased in, affecting vehicle models produced between 2017 and 2025. The tailpipe emissions standards for light-duty vehicles will reduce the sum of non-methane organic gases and nitrogen oxides per fleet average from 160 mg per mile to 30 mg per mile. The tailpipe emissions standards for particulate matter will be lowered to 3 mg per mile per vehicle from 10 mg per mile. Evaporative-emission standards would fall 50%. Changes to emission test-fuel specifications are also proposed.

Source: EPA