US EPA proposes to strengthen NAAQS standards for ozone

26 November 2014

The US Environmental Protection Agency (EPA) has proposed to strengthen the National Ambient Air Quality Standards (NAAQS) for ozone to within a range of 65 to 70 ppb, while taking comment on a level as low as 60 ppb. The current 8-hour ozone standard of 75 ppb was set in 2008. Under the US Clean Air Act, the EPA is supposed to review the standards every five years.

EPA scientists examined more than 1,000 new scientific studies published since the last update. The studies indicate—said the agency—that exposure to ozone at levels below 75 ppb can pose serious threats to public health, harm the respiratory system, cause or aggravate asthma and other lung diseases, and is linked to premature death from respiratory and cardiovascular causes. Ground level ozone forms in the atmosphere when emissions of nitrogen oxides and volatile organic compounds react in the sun from sources like cars, trucks, buses, industries, power plants and certain fumes from fuels, solvents and paints. People most at risk from breathing air containing ozone include people with asthma, children, older adults, and those who are active or work outside. In the United States, 1 in 10 children has been diagnosed with asthma, said the EPA.

According to EPA’s analysis, strengthening the ozone standard to a range of 65 to 70 ppb will provide significantly better protection for children, preventing from 320,000 to 960,000 asthma attacks and from 330,000 to 1 million missed school days. Strengthening the standard to a range of 70 to 65 ppb would better protect both children and adults by preventing more than 750 to 4,300 premature deaths; 1,400 to 4,300 asthma-related emergency room visits; and 65,000 to 180,000 missed workdays.

The agency is also proposing to strengthen the “secondary” ozone standard to a level within 65 to 70 ppb to protect plants, trees and ecosystems from damaging levels of ground-level ozone.

The EPA anticipates that the vast majority of US counties with ozone monitors would meet the proposed standards by 2025 with the pollution reduction rules and programs that are already in place or underway.

However, the proposal is likely to face opposition in the US Congress. Oklahoma Senator Jim Inhofe, the incoming chairman of the Senate Environment and Public Works Committee, issued a statement saying that the proposed standards would harm the economy and that the EPA proposal “will face rigorous oversight” from the new Congress.

The EPA will seek public comment on the proposal for 90 days following publication in the Federal Register. The agency plans to finalize the new ozone standards by October 1, 2015.

Source: US EPA