Characteristics of Organic and Elemental Carbon in PM2.5 and PM0.25 in Indoor and Outdoor Environments of a Middle School: Secondary Formation of Organic Carbon and Sources Identification

Abstract

Secondary organic carbon (SOC) formation and its effects on human health require better understanding in Chinese megacities characterized by a severe particulate OPEN ACCESSAtmosphere 2015, 6 362 pollution and robust economic reform. This study investigated organic carbon (OC) and elemental carbon (EC) in PM2.5 and PM0.25 collected 8-20 March 2012. Samples were collected inside and outside a classroom in a middle school at Xi'an. On average, OC and EC accounted for 20%-30% of the particulate matter (PM) mass concentration. By applying the EC-tracer method, SOC's contribution to OC in both PM size fractions was demonstrated. The observed changes in SOC:OC ratios can be attributed to variations in the primary production processes, the photochemical reactions, the intensity of free radicals, and the meteorological conditions. Total carbon (TC) source apportionment by formula derivation showed that coal combustion, motor vehicle exhaust, and secondary formation were the major sources of carbonaceous aerosol. Coal combustion appeared to be the largest contributor to TC (50%), followed by motor vehicle exhaust (25%) and SOC (18%) in both size fractions.

Assessment of Indoor-Outdoor Particulate Matter Air Pollution: A Review

“…The recurrence of the use non-typical PM classes (i.e., PM 5 , PM 4 , PM 1 ) is also found in many studies, frequently joint with the most-used indicators [49,50,54,57,62,71].…”

Air pollution of beauty salons by cosmetics from the analysis of suspensed particulate matter

“…Ambient elemental carbon (EC) comes from incomplete combustion of materials containing carbon; in southern Poland, in spring and summer, PM-bound EC comes mainly from car exhaust emissions (Rogula-Kozłowska et al 2014; Rogula-Kozłowska 2014, 2015). Indoor PM-bound organic and elemental carbon comes from outdoor air or indoor sources (Gupta and Bhandari 2011;Xu et al 2015;Rogula-Kozłowska et al 2017).…”

“…The ambient secondary compounds arising from VOCs in photochemical reactions or from organic vapor condensation have relatively low molecular weights and boiling temperatures (Froines and Garabrant 1986;Cosmetic Ingredient Review 2008;Xu et al 2015;Lachenmeier et al 2017). During the analysis of PM for OC, they are released as OC1 at the temperature not exceeding 200 °C (Cavalli et al 2010).…”

The Roles of N, S, and O in Molecular Absorption Features of Brown Carbon in PM2.5 in a Typical Semi‐Arid Megacity in Northwestern China

“…PM 2.5 samples were collected on pre-combusted quartz filters (780°C for 5 h) using a mid-volume (50 L min −1 ) air sampler (HVS-PM 2.5 , Thermo-Anderson Inc., Waltham, MA, USA) from January 1 to January 6 (winter) and from July 24 to August 5 (summer), 2017. Compared with the winter data presented in Zeng et al (2020), sampling in summer was added to gain a full understanding of BrC in Xi'an because the large discrepancies of emissions, diffusion, and transformation between the two seasons (Du et al, 2013;Shen et al, 2008;Xu et al, 2015). Highly time-resolved PM 2.5 samples were collected on each sampling day with time-intervals of 00:00-03:00, 03:00-07:00, 07:00-10:00, 10:00-13:00, 13:00-18:00, 18:00-21:00, and 21:00-00:00 LST.…”