Review of Sunset OC/EC Instrument Measurements During the EPA’s Sunset Carbon Evaluation Project
Steven Brown,
Hilary Minor,
Theresa O’Brien,
Yousaf Hameed,
Brandon Feenstra,
Dustin Kuebler,
Will Wetherell,
Robert Day,
Richard Tun,
Elizabeth Landis,
Joann Rice
Affiliations
Steven Brown
Sonoma Technology, Inc., 1450 N. McDowell Blvd., Suite 200, Petaluma, CA 94954, USA
Hilary Minor
Sonoma Technology, Inc., 1450 N. McDowell Blvd., Suite 200, Petaluma, CA 94954, USA
Theresa O’Brien
Sonoma Technology, Inc., 1450 N. McDowell Blvd., Suite 200, Petaluma, CA 94954, USA
Yousaf Hameed
Department of Air Quality, Clark County, 4701 W. Russell Rd. Suite 200, Las Vegas, NV 89118, USA
Brandon Feenstra
South Coast Air Quality Management District, 21865 Copley Dr. Diamond Bar, CA 91765-4178, USA
Dustin Kuebler
Missouri Department of Natural Resources, P.O. Box 176, Jefferson City, MO 65102, USA
Will Wetherell
Missouri Department of Natural Resources, P.O. Box 176, Jefferson City, MO 65102, USA
Robert Day
Department of Energy and Environment, Government of the District of Columbia, 1200 First Street, N.E. 5th Floor, Washington, DC 20002, USA
Richard Tun
Department of Energy and Environment, Government of the District of Columbia, 1200 First Street, N.E. 5th Floor, Washington, DC 20002, USA
Elizabeth Landis
U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Ambient Air Monitoring Group, Mail Code C304-06, Research Triangle Park, NC 27711, USA
Joann Rice
U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Ambient Air Monitoring Group, Mail Code C304-06, Research Triangle Park, NC 27711, USA
To evaluate the feasibility of the Sunset semicontinuous organic and elemental carbon (OC/EC) monitor, the U.S. Environmental Protection Agency (EPA) sponsored the deployment of this monitor at Chemical Speciation Network (CSN) sites with OC and EC measurements via quartz fiber filter collection in Chicago, Illinois; Houston, Texas; Las Vegas, Nevada; St. Louis, Missouri; Rubidoux, California; and Washington, D.C. Houston, St. Louis, and Washington also had collocated Aethalometer black carbon (BC) measurements. Sunset OC generally compared well with the CSN OC (r2 = 0.73 across five sites); the Sunset/CSN OC ratio was, on average, 1.06, with a range among sites of 0.96 to 1.12. Sunset thermal EC and CSN EC did not compare as well, with an overall r2 of 0.22, in part because 26% of the hourly Sunset EC measurements were below the detection limit. Sunset optical EC had a much better correlation to CSN EC (r2 = 0.67 across all sites), with an average Sunset/CSN ratio of 0.90 (range of 0.7 to 1.08). There was also a high correlation of Sunset optical EC with Aethalometer BC (r2 = 0.77 across all sites), though with a larger bias (average Sunset/Aethalometer ratio of 0.56). When the Sunset instrument was working well, OC and OptEC data were comparable to CSN OC and EC.
