Skip to Content
Streetsblog USA home
Streetsblog USA home
Log In
Air Quality

EPA Strengthens Nitrogen Dioxide Rules for First Time in 35 Years

The Environmental Protection Agency (EPA) today announced a new "one-hour standard" aimed at limiting Americans' short-term exposure to nitrogen dioxide (NO2), a pollutant created by cars, power plants, and other industrial sources.

US_regulate_national_auto_emissions.jpg(Photo: TreeHugger)

NO2, a main ingredient in smog, is linked to adverse respiratory health effects such as chronic asthma. In creating a new one-hour NO2 exposure limit of 100 parts per billion (ppb), the EPA noted that the risk of short-term NOX exposure is particularly acute near major highways.

As EPA chief Lisa Jackson said in a statement:

This new one-hour standard is designed toprotect the air we breathe and reduce health threats for millions ofAmericans. For the first time ever, we are working to preventshort-term exposures in high risk NO2 zones like urban communities andareas near roadways. Improving air quality is a top priority for this EPA. We’re movinginto the clean, sustainable economy of the 21st century, defined byexpanded innovation, stronger pollution standards and healthiercommunities.

The rule will be enforced by setting up monitors near roads in areas with more than 500,000 residents, according to the agency, with a deadline of 2013 for the beginning of pollutant tracking. The EPA said it plans to work directly on 40 new monitors for cities and towns with the most significant NO2 exposure.

It's worth noting, however, that major cities have remained out of compliance with EPA air-quality standards for years without losing significant amounts of federal highway money, as the federal government often threatens. Moreover, the EPA has not changed the current annual NO2 standard of 53 ppb.

Stay in touch

Sign up for our free newsletter

More from Streetsblog USA

Advocates Get D.C. Mayor To Release Buried Report On The Potential Benefits Of Congestion Pricing

How many other conversations about congestion pricing across the country are being suppressed — and how many have never even gotten started?

March 19, 2026

Why Some Congresspeople Want to Go Big on Greenways

A new bill would multiply federal funding for walking and biking paths — even as some powerful congresspeople threaten to take away what we've already got.

March 18, 2026

Wednesday’s Headlines Would Walk if We Could

It would be nice if the Trump administration would let us.

March 18, 2026

Opinion: The Federal Railroad Administration’s Proposed Amtrak Restructuring is Worth Considering

The federal push to overhaul Amtrak operations is promising, but it must be done with care

March 18, 2026

Why Transit Advocates Aren’t 100% Behind This Senator’s Bold Bill To Slash Highway Funding

A new Republican bill could bring rampant highway overspending to a halt and slash emissions by one-fifth. But don't get too excited because it would hurt transit, too.

March 17, 2026

Tuesday’s Headlines Are Underwater

More and more people can't afford their car payments or associated costs — which wouldn't be as big of a problem if they had a choice other than driving.

March 17, 2026
See all posts