Spatial and seasonal variations of secondary organic aerosol from terpenoids over China

Abstract

A majority of global secondary organic aerosol (SOA) comes from terpenoids. In this study, we carried out a 1 year nationwide observation of pinenes (α‐ and β‐pinene) and SOA tracers from monoterpenes (SOAM) and β‐caryophyllene (SOAC) over China for the first time. SOAM and SOAC tracers ranged from 9.80 to 49.0 ng m−3 and 1.72 to 7.72 ng m−3, respectively, with high levels in southern China. Pinenes ranged from 34 to 102 parts per trillion by volume, with α‐pinene dominant over β‐pinene. SOAM tracers were correlated between paired sites, suggesting a regional impact of SOAM, while pinenes were uncorrelated between sites due to their rapid oxidation. High levels of SOAM tracers were observed in spring and summer. However, at the Hailun site in Northeast China, SOAM tracers increased during winter. The positive correlation between SOAM tracers and the biomass burning (BB) tracer levoglucosan during winter at Hailun indicated that the unexpected increase of SOAM was associated with BB. The SOAC tracer, β‐caryophyllenic acid, increased during winter and was positively correlated with levoglucosan, suggesting substantial contributions from BB to SOAC production in wintertime. Together with SOA tracers from isoprene, these tracers were applied to estimate biogenic secondary organic carbon (BSOC) from isoprene, monoterpenes, and β‐caryophyllene. The annual average BSOC was 0.91 ± 0.41 μgC m−3,with the majority from monoterpenes and the highest level in Southwest China. BSOC was elevated from April to September and was lowest in January and February. BSOC composition dramatically changed from a monoterpene majority in fall‐spring to an isoprene majority in summer.

Molecular characterization of organic aerosols in the Kathmandu Valley, Nepal: insights into primary and secondary sources

“…The annual average concentration 440 of the total M-SOA tracers was 59.3±24.6 ng m -3 (Table 1). The concentration of M-SOA tracers was higher than those reported in the previous studies from the urban site in Kunming (annual average: 44.1 ±38.8 ng m -3 ) (Ding et al, 2016b), three cities (Ohio, Michigan and California) in North America (summer: 30.4-60.6 ng m -3 ) (Stone et al, 2009) and a forest site in Hyytiä lä , Europe (summer: 15.1-33.3 ng m -3 ) .…”

Contribution from Selected Organic Species to PM2.5 Aerosol during a Summer Field Campaign at K-Puszta, Hungary

“…Considering that various uncertainties are associated with the approach of Kleindienst et al [39], as also indicated by these authors and in other publications since then [3,43,44,46], we estimate that the uncertainty that is associated with the SOC M and SOC I contributions to the OC is at least a factor of 2.…”

“…Considering that the annual average OC at the 12 sites ranged from 22 to 54 µgC/m 3 , this means that the percentages of SOC M and SOC I in OC were only around 1% each. Ding et al [46] also noted that biogenic SOC was elevated from April to September and was lowest in January and February, and that its composition changed dramatically from a monoterpene majority in fall-spring to an isoprene majority in summer. The authors further stated that the relative standard deviations were 53% for SOC M and 47% for SOC I and that because of various other uncertainties involved in the approach, their results should have underestimated the total amount of biogenic SOC in the air in China.…”

“…Also, for some recent studies in China, use was made of the Kleindienst et al [39] approach. For their one-year study at 12 sites across six regions of China, Ding et al [46] found average annual concentrations of 0.17 to 0.83 µgC/m 3 for SOC M and 0.03 to 0.63 µgC/m 3 for SOC I . Considering that the annual average OC at the 12 sites ranged from 22 to 54 µgC/m 3 , this means that the percentages of SOC M and SOC I in OC were only around 1% each.…”

Impact of anthropogenic emissions on biogenic secondary organic aerosol: observation in the Pearl River Delta, southern China

“…In polluted regions, the increase in O 3 levels due to high emissions of NO x and VOCs likely results in significant SOA formation via the ozonolysis of BVOCs (Sipilä et al, 2014;Riva et al, 2017). In addition, the large emission and formation of anthropogenic organic matter (OM) in urban areas enhance the incorporation of BVOC oxidation products into the condensed phase (Donahue et al, 2006). Recently, Carlton et al (2018) found that the removal of anthropogenic emissions of NO x , SO 2 , and primary OA in the Community Multiscale Air Quality Model (CMAQ) simulations could reduce BSOA by 23 %, 14 %, and 8 % in summertime, respectively.…”