On March 7, 2013, EPA issued a final rule delaying deadlines to install near-road nitrogen dioxide air quality monitors. The near-road monitoring program, included in EPA's 2010 update to then nitrogen dioxide NAAQS, initially required a 126 new nitrogen dioxide  monitors to be installed by January 1, 2013. State and local air officials voiced concern that they would not be able to meet the monitoring mandate because they lacked sufficient financial resources to install and operate the new monitoring sites. 

As a part of its final rule, EPA has instituted a phased approach whereby an initial wave of monitors must be installed by January 1, 2014 (52 monitors in urban areas with a population of one million or more), with another set of monitors due on January 1, 2015 (23 additional monitors for densely populated and high-traffic areas), and a final set due on January 1, 2017 (51 remaining required monitors). EPA did not respond, however, to comments requesting that it delay attainment designations until the full monitoring network is operational.

This final rule applies to the deadlines for near-road monitors, but does not affect requirements in the 2010 nitrogen dioxide NAAQS related to additional area-wide monitors and monitors to measure nitrogen dioxide impacts on vulnerable populations. Under these provisions, the requirement to install 40 additional monitors nationwide took effect January 1, 2013.