For people living or working near busy roads, a national monitoring decision and a local pollution reading answer different questions. EPA's December 30, 2016 final rule removed the scheduled near-road nitrogen dioxide monitoring requirement for Core Based Statistical Areas with at least 500,000 but fewer than 1,000,000 people. This January 1 retrospective concerns that earlier decision, which took effect December 30. [2016-31645]

The removed installation requirement had been due January 1, 2017. Its removal does not document a closure of existing stations. Nor does it remove the separate area-wide or vulnerable-population monitoring requirements. EPA described those as distinct parts of the network, with different purposes from the near-road tier affected by this action. A smaller area's population alone cannot describe every resident's exposure. [2016-31645]

The May 16 proposal supplied the rationale: available near-road measurements were below the relevant national standards, and EPA expected similar or more likely lower concentrations in smaller areas. But the proposal also described variation with traffic, vehicle mix, terrain and weather. Data collection had begun at different times across sites, and the proposal's 2015 analysis used only the first three quarters. [2016-11507]

That leaves a concrete public-interest distinction. The documents support an explanation of why EPA reduced the required network; they do not supply a measurement for every unmonitored location or establish that all local air is safe. Proposal and final rule are one agency evidence chain. Residents evaluating the change need the difference between a population-based monitoring obligation and evidence about the particular road beside them kept visible. [2016-31645][2016-11507]

Source documents

  1. Revision to the Near-road NO2 Minimum Monitoring Requirementshttps://www.govinfo.gov/content/pkg/FR-2016-12-30/html/2016-31645.htm
  2. Revision to the Near-Road NO2 Minimum Monitoring Requirementshttps://www.govinfo.gov/content/pkg/FR-2016-05-16/html/2016-11507.htm