Proposed Revisions to Ambient Monitoring Quality Assurance and Other Requirements

On September 11, 2014, the Environmental Protection Agency (EPA) proposed “Revisions to Ambient Monitoring Quality Assurance and Other Requirements” (40 CFR Part 58) by providing clarity to reduce the compliance burden on monitoring agencies operating ambient air monitoring networks for criteria pollutants. The rulemaking applies to state, territorial, and local air management programs and it proposes to make revisions to the monitoring requirements of 40 CFR Part 58, the associated Appendices A, D, new Appendix B along with operating schedules, development of annual monitoring network plans, data reporting and certification requirements, public notice requirements, revising network design criteria for non-source Lead (Pb) monitoring, addressing air quality surveillance requirements and operation of required quality assurance (QA) program. A brief summary of some of the revisions are listed categorically as follows:

Subpart A - General Provisions (Definitions)

The naming of certain terms are revised to ensure uniformity, clarity and also broaden the definitions across the entire array of monitoring regulations. New definitions are added to accommodate the new terms under Appendix B. Certain terms are deleted to ensure consistency between the National Ambient Air Quality Standards (NAAQS) rulemakings for criteria pollutants.

Subpart B - Monitoring Network

Multiple revisions have been proposed under this subpart which cover various topics ranging from network assessments, monitoring network plans, technical requirements, operating schedules, data certifications, data submittals and archiving requirements. The revisions also include language with associated changes arising from updated Appendix A and new Appendix B. The summary of changes are as follows:

  • Revisions to the comment process by updating the regulatory language in 40 CFR 58.10(a) for the monitoring agencies to collect and include public comments along with the network modification plans before submitting plans to the EPA regional offices. The rule also proposes to update the content list under 40 CFR 58.10(b) by adding network description and associated language in the annual monitoring network plans.
  • Revisions to the sampling frequency are proposed by updating the regulatory language in 40 CFR 58.12 with respect to design values and their relation to sampling frequencies.
  • Revise the regulatory language in 40 CFR 58.14(a) to submit the findings of 5-year network assessments as part of the annual monitoring network plans.
  • Revisions to the data certification requirements to formulate a streamlined process. It is also proposed that these air quality system (AQS) reports be submitted to the Regional Administrator as opposed to the usual practice of submitting via the Regional Administrator to the Administrator.
  • Revision to remove the language pertaining to AQS reporting requirements of daily average temperatures and average pressure related to PM2.5 and Pb measurements.
  • Revision to change the reporting schedule in 40 CFR 58.16(b) and (d) from 90 days to 6 months at the end of each quarter for PM2.5 chemical speciation data which allows adequate review time and provide flexibility for EPA and the monitoring agencies.
Appendices A and B

Appendix A is being reorganized due to separation of Appendix B from A. The entire Appendix A is being reprinted but EPA is accepting comments solely on the provisions that are revised as part of this proposed rulemaking. The proposed rule has revisions associated with reorganization of Appendices A and B. The existing Appendix A has the monitoring requirements for Prevention of Significant Deterioration (PSD), State or Local Air Monitoring Stations (SLAMS) and Special Purpose Monitors (SPM). PSD monitoring is for projects that are subject to PSD air permitting requirements (i.e., they are pursued by owner/operator seeking a PSD permit). SLAMS and SPM are required for implementation of and compliance with NAAQS (i.e., responsibility of state/local agency). In other words, the responsible entities for handling these programs are different. Historically, there were issues with misinterpretations of regulations and also the requirements to perform necessary quality control (QC) requirements depending on the type of monitoring program. The current rule proposes to separate the PSD QA requirements from Appendix A and move them to Appendix B to create flexibility, ease future rulemaking(s), and avoid confusions between the responsible agencies. Other proposed revisions outlined for the monitoring programs under Appendices A and B include information and procedures for quality system requirements, QC checks for gases, particulate monitors and calculations for data quality assessments.

Appendix D

The two revisions proposed are related to the measurements taken as part of the NCore network. The first one addresses a minor change associated with deleting the requirements to measure the speciated PM10-2.5 to ensure consistency across the different sections of Appendix D. The second revision addresses the deletion of requirement to measure Pb at urban NCore sites, both Pb in Total Suspended Particles (Pb-TSP) or as Pb-PM10.

The USEPA will accept comments on this proposed rule until November 10, 2014. Comments can be submitted online by visiting, or by emailing