Zhang, Xiaolu Kim, Hwajin Parworth, Caroline L. Young, Dominique E. Zhang, Qi Metcalf, Andrew R. Cappa, Christopher D. 2024-01-20T05:01:00Z 2024-01-20T05:01:00Z 2021-09-05 2016-02-16 0013-936X https://pubs.kist.re.kr/handle/201004/124378 The optical properties, composition and sources of the wintertime aerosols in the San Joaquin Valley (SJV) were characterized through measurements made in Fresno, CA during the 2013 DISCOVER-AQ campaign. PM2.5 extinction and absorption coefficients were measured at 405, 532, and 870 nm along with refractory black carbon (rBC) size distributions and concentrations. BC absorption enhancements (E-abs) were measured using two methods, a thermodenuder and mass absorption coefficient method, which agreed well. Relatively large diurnal variations in the E-abs at 405 nm were observed, likely reflecting substantial nighttime emissions of wood burning organic aerosols (OA) from local residential heating. Comparably small diurnal variations and absolute nighttime values of E-abs were observed at the other wavelengths, suggesting limited mixing-driven enhancement. Positive matrix factorization analysis of OA mass spectra from an aerosol mass spectrometer resolved two types of biomass burning OA, which appeared to have different chemical composition and absorptivity. Brown carbon (BrC) absorption was estimated to contribute up to 30% to the total absorption at 405 nm at night but was negligible (<10%) during the day. Quantitative understanding of retrieved BrC optical properties could be improved with more explicit knowledge of the BC mixing state and the distribution of coating thicknesses. English American Chemical Society PM2.5 SOURCE CONTRIBUTIONS PARTICLE SOOT PHOTOMETER ABSORPTION CROSS-SECTION AMBIENT BLACK CARBON SAN-JOAQUIN VALLEY BROWN CARBON LIGHT-ABSORPTION ORGANIC-CARBON COMPREHENSIVE CHARACTERIZATION AIRCRAFT INSTRUMENT Optical Properties of Wintertime Aerosols from Residential Wood Burning in Fresno, CA: Results from DISCOVER-AQ 2013 Article 10.1021/acs.est.5b04134 1 Environmental Science & Technology, v.50, no.4, pp.1681 - 1690 Environmental Science & Technology 50 4 1681 1690 scie scopus 000370454200007 2-s2.0-84958267803 Engineering, Environmental Environmental Sciences Engineering Environmental Sciences & Ecology Article PM2.5 SOURCE CONTRIBUTIONS PARTICLE SOOT PHOTOMETER ABSORPTION CROSS-SECTION AMBIENT BLACK CARBON SAN-JOAQUIN VALLEY BROWN CARBON LIGHT-ABSORPTION ORGANIC-CARBON COMPREHENSIVE CHARACTERIZATION AIRCRAFT INSTRUMENT