The Smog Blog:

For the first time in 35 years, the EPA has proosed setting a new one-hour standard and establishing a roadside monitoring network for nitrogen dioxide, a widespread, noxious air pollutant. 

The Agency will be takinig public comment on the proposal at two public hearings in early August:

August 3, 2009 at the EPA Potomac Yard Conference Center in Arlington, Virginia; and

August 6, 2009 at the Sheraton Los Angeles Downtown.

EPA has proposed setting a 1-hour standard between 80-100 ppb, but the American Lung Association supports a standard of 50 ppb to protect the health of sensitive popultions with an adequate margin of safety.  An hourly standard of 50 ppb is needed to keep kids with asthma out of the emergency room due to serious asthma attacks. 

• Since EPA’s last review in 1996, over 50 peer-reviewed community health studies have been published examining the effects of short-term nitrogen dioxide concentrations on the rate of hospital admissions and emergency room visits for breathing problems. Effects occur when daily levels are well below the current annual standard of 53 ppb.

• A synthesis of data from 19 controlled human exposure studies of adults found that 66 percent of mild asthmatics experienced increased airway responsiveness following 1-hour exposures to 100 ppb.  This twitchiness of the airways is a hallmark of asthma.  In setting standards, safety factors must be incorporated to account for potential effects on infants, children, and those with moderate or severe asthma who were not tested. 

• EPA’s draft benefits analysis shows that an hourly standard of 50 ppb would provide the greatest benefit to public health by reducing asthma exacerbations and hospital admissions and emergency room visits for respiratory causes.

Hundreds of recent studies have reported associations between residence near heavily trafficked highways and adverse health effects, but there is currently no national minitoring network for traffic pollution.  The proposal to do roadside monitoring for nitrogen dioxide is a step in the right direction but it needs to be expanded to include other traffic pollutants such as fine particles. 

To speak at the public hearings, sign up with EPA's Tricia Crabtree at crabtree.tricia@epa.gov, or 919-541-5688. 

Written comments are due by Spetember 14, 2009.  More information is available at www.CleanAirStandards.org. 

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