April 17, 2020
Memorandum
SUBJECT:	Data files related to quantitative analyses included as a part of the review of the secondary National Ambient Air Quality Standards for Particulate Matter
      (EPA-HQ-OAR-2015-0072)

FROM:	Regina Chappell
		Office of Air Quality Planning and Standards

TO:	Rulemaking Docket for the Review of the National Ambient Air Quality Standards for Particulate Matter (EPA-HQ-OAR-2015-0072)


Data files used in the quantitative visibility analyses included as a part of the review of the secondary National Ambient Air Quality Standards (NAAQS) for Particulate Matter (PM), as described in the Policy Assessment and the Notice of Proposed Rulemaking, are listed and briefly described in Table 1 below. The EPA has temporarily suspended its Docket Center and Reading Room for public visitors to reduce the risk of transmitting COVID-19. The data files listed below may be requested through the Docket Center. Please contact the Docket Center through this website for specific information and questions concerning this docket and its content: https://www.epa.gov/dockets/forms/contact-us-about-docket-center-website. The data files in Table 1 are also publicly available at: https://www.epa.gov/air-quality-analysis/particulate-matter-naaqs-review-analyses-and-data-sets.


Table 1. Data file names and descriptions related to quantitative analyses included as a part of the review of the secondary PM NAAQS
                                   File Name
                                   File Size
                               File Description
Site_dv_daily_light_extencton_comparison.xlsx
                                     94 K
Site design value vs visibility index comparison 2015-2017
revised_improve_frh.csv
                                      3 K
f(RH) values for calculating light extinction
 rhum_2m_2015_2017.zip
      Includes:
           rhum.2m.2015.nc
           rhum.2m.2016.nc
          rhum.2m.2017.nc
                                     172 MB
 North American Regional Reanalysis (NARR) relative humidity data as the local time daily average for 2015-2017
 pm25_2015_2017_daily_concentrations.zip
                                      8 MB
 Daily PM2.5 concentrations for 2015-2017
 coarse_2015_2017_daily_concentrations.zip
                                     676 K
 Daily PM10-2.5 concentrations for 2015-2017
 speciation_2015_2017_daily_concentrations.zip
                                     16 MB
 Daily PM2.5 speciation concentrations for 2015-2017

