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EPA Proposes Tightening Air Quality Standards for Ground Level Ozone

Late last month, the U.S. EPA unveiled plans to tighten the nation’s air quality standard for ground level ozone pollution. Ozone forms in the atmosphere when nitrogen oxides and volatile organic compounds combine in the presence of sunlight. The agency periodically reviews and assesses the need for such tightening, and in the case of ozone (sometimes called smog) it has lowered the permissible pollution levels several times since the 1990s. The latest proposal would, if finalized, lower levels from their current level of 75 parts per billion (ppb) to somewhere within a range of 65–70 ppb. EPA however also intends to consider comments on setting a level as low as 60 ppb. An EPA Fact Sheet indicates that the expected health benefits of such a rule would be valued at $6.5–$13 billion annually in 2025 if the standard were set at 70 ppb and $19–$38 billion annually if the level is set at 65 ppb; cost calculations exclude benefits associated with California because it likely would come into compliance later. The Fact Sheet also indicates that most areas of the country will meet the new standard by 2025 based on programs currently in place or under way.

EPA intends to take comment on the proposal and issue final rules by October 2015. It would then have until October 2017 to designate the attainment and non-attainment areas across the country. States would have until 2020 to 2037 to come into compliance and achieve attainment with the new standard. Compliance deadlines would vary by the severity of non-attainment. The new rule also includes a requirement to expand period of the year in which states must record pollution readings for ground-level ozone. Tightening of the standards likely will put added pressure on the need to lower motor vehicle pollution, a major source of emissions of nitrogen oxides and volatile organic compounds. Comments on the proposal will be due 90 days from publication in the Federal Register.

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