Organic functional groups in aerosol particles from burning and non-burning forest emissions at a high-elevation mountain site

Abstract

Abstract. Ambient particles collected on teflon filters at the Peak of Whistler Mountain, British Columbia (2182 m a.s.l.) during spring and summer 2009 were measured by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFG). The project mean and standard deviation of organic aerosol mass concentrations (OM) for all samples was 3.2±3.3 (µg m −3 ). Measurements of aerosol mass fragments, size, and number concentrations were used to separate fossil-fuel combustion and burning and non-burning forest sources of the measured organic aerosol. The OM was composed of the same anthropogenic and non-burning forest components observed at Whistler mid-valley in the spring of 2008; during the 2009 campaign, biomass burning aerosol was additionally observed from fire episodes occurring between June and September. On average, organic hydroxyl, alkane, carboxylic acid, ketone, and primary amine groups represented 31 %±11 %, 34 %±9 %, 23 %±6 %, 6 %±7 %, and 6 %±3 % of OM, respectively. Ketones in aerosols were associated with burning and non-burning forest origins, and represented up to 27 % of the OM. The organic aerosol fraction resided almost entirely in the submicron fraction without significant diurnal variations. OM/OC mass ratios ranged mostly between 2.0 and 2.2 and O/C atomic ratios between 0.57 and 0.76, indicating that the organic aerosol reaching the site was highly aged and possibly formed through secondary formation processes.

Organic functional groups in the submicron aerosol at 82.5° N, 62.5° W from 2012 to 2014

“…There were 4 weeks with detectable carbonyl groups and with OM / nss-SO 3). For those weeks, the carbonyl groups correlate strongly with EC and nss-K + (CoD > 0.96 and t stat > 7), and the average functional groups' composition (45 % alkane groups, 36 % carbonyl groups and 9 % amine groups) corresponds closely with the OFG pattern of Takahama et al (2011). The 4 weeks were during periods with significant forest fire activity in the Northern Hemisphere and warmer temperatures at Alert.…”

“…A higher fraction of carbonyl groups and higher OM / nss-SO = 4 can be prominent features of BB particles (e.g., Takahama et al, 2011). There were 4 weeks with detectable carbonyl groups and with OM / nss-SO 3).…”

Liquid–liquid phase separation in particles containing organics mixed with ammonium sulfate, ammonium bisulfate, ammonium nitrate or sodium chloride

“…The organics investigated had a wide range of oxygen-to-carbon elemental ratios (O : C) (from 0.29 to 1.33), covering the most of the range of O : C often observed in atmospheric particles (approximately 0.1 to 1.0) Chen et al, 2009;Jimenez et al, 2009;Hawkins et al, 2010;Heald et al, 2010;Ng et al, 2010;Takahama et al, 2011). The organic species studied herein also included several functional groups observed in atmospheric samples (e.g.…”

ORACLE (v1.0): module to simulate the organic aerosol composition and evolution in the atmosphere

“…In contrast to highly populated areas, long-term observations of OA over forests are unavailable; therefore we have collected OA data measured during the short-term field campaigns of DABEX, DODO, and AMMA over subtropical West Africa (Capes et al, 2008(Capes et al, , 2009); AMAZE-08 and SAMBBA over the Amazon rainforest (Chen et al, 2009;Brito et al, 2014); and measurement data collected over the Canadian boreal forest (Schwartz et al, 2010;Takahama et al, 2011). Capes et al (2008) …”