Based on its review of the air quality criteria for oxides of nitrogen and the primary national ambient air quality standard (NAAQS) for oxides of nitrogen as measured by nitrogen dioxide (NO<INF>2</INF>), EPA is making revisions to the primary NO<INF>2</INF> NAAQS in order to provide requisite protection of public health. Specifically, EPA is establishing a new 1-hour standard at a level of 100 ppb, based on the 3-year average of the 98th percentile of the yearly distribution of 1-hour daily maximum concentrations, to supplement the existing annual standard. EPA is also establishing requirements for an NO<INF>2</INF> monitoring network that will include monitors at locations where maximum NO<INF>2</INF> concentrations are expected to occur, including within 50 meters of major roadways, as well as monitors sited to measure the area-wide NO<INF>2</INF> concentrations that occur more broadly across communities.