In light of current delays in federal funding, the EPA has issued a final rule providing more time to states to meet their requirements for near-road nitrogen dioxide (NO2) monitoring operations.  The current action specifically replaces the previous January 1, 2013, deadline established in a February 2010 rule that amended the NO2 national ambient air quality standards (NAAQS) with a phased approach that spaces out deadlines for both submitting monitoring plans and for activating monitoring equipment between July 1, 2013, and January 1, 2017.  Timing for two other monitoring provisions—areawide monitoring and monitoring to characterize NO2 exposures for susceptible and vulnerable populations—are unchanged from the February 2010 rule.

1-hour NO2 NAAQS

In the February 2010 action, the EPA established a new 1-hour standard of 100 parts per billion NO2 to supplement the existing annual standard.  The rule also requires that states meet new NO2 monitoring requirements based on a tiering approach.  In Tier 1, all core-based statistical areas(CBSA) with a population of 500,000 or more must have at least one monitor at a location of expected maximum hourly NO2 concentrations and a second monitor at a roadway segment with 250,000 or greater annual average daily traffic counts. 

In Tier 2, areawide monitors must be placed in a location of expected highest NO2 concenrations in any CBSA with a population of 1 million or more.  Tier 3 monitors must be placed to ensure protection of susceptible and vulnerable populations.  States were required to submit plans for establishing all required NO2 monitoring sites by July 1, 2012, and all sites were required to be operational by January 1, 2013.

Tier 1

The current amendments make the following changes, which are applicable only to Tier 1. 

• In each CBSA with 1 million or more persons, one near-road NO2 monitor must be reflected in the state annual monitoring network plan submitted July 1, 2013, and that monitor must be operational by January 1, 2014.
• In each CBSA required to have two near-road NO2 monitors (i.e., any CBSA with a population of 2,500,000 or more persons, or any CBSA with a population of 500,000 or more persons that has one or more roadway segments with 250,000 or greater annual average daily traffic counts), a second near-road NO2 monitor must be reflected in the state annual monitoring plan submitted July 1, 2014, and that monitor must be operational by January 1, 2015.
• In each CBSA with 500,000 or more persons (but less than 1 million), one near-road NO2 monitor must be reflected in the state annual monitoring plan submitted July 1, 2016, and that monitor must be operational by January 1, 2017.

In making the timing changes, the EPA said there will always be a need to balance monitoring objectives and requirements with available resources.  “The agency believes that the phased approach is the best solution to match the forecasted availability of federal funding, which will have to occur over multiple years, to allow the implementation of the required near-road NO2 network,” states the Agency.

The final rule also amends regulatory language to direct states to submit their annual monitoring plans to the Agency’s regional administrators rather than the EPA administrator.

Final changes to the NO2 NAAQS monitoring requirements were published in the March 14, 2013, FR.