35 Year Old Nitrogen Dioxide Standard Begs for Revision
The current standard for nitrogen dioxide — an annual average standard — was set in 1971 and has not been revised since then. In the past 35 plus years there has been a great deal of evidence pointing to the need for a short-term standard. Short-term exposures to nitrogen dioxide are associated with increased airway responsiveness, particularly in children and asthmatics. Studies of respiratory symptoms, emergency department visits and hospital admissions report increased risks with nitrogen dioxide even in areas where daily concentrations never go above the level of the current annual average standard (53 ppb).
EPA is currently reviewing the National Ambient Air Quality Standards (NAAQS) for nitrogen dioxide, and issued a draft risk and exposure assessment for public comment. The American Lung Association’s technical comments on the draft are posted below.
