scholarly journals Emission inventory of semi-volatile and intermediate-volatility organic compounds and their effects on secondary organic aerosol over the Pearl River Delta region

2019 ◽  
Vol 19 (12) ◽  
pp. 8141-8161 ◽  
Author(s):  
Liqing Wu ◽  
Xuemei Wang ◽  
Sihua Lu ◽  
Min Shao ◽  
Zhenhao Ling
Keyword(s):  
Organic Compounds ◽  
Pearl River Delta ◽  
Emission Inventory ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Pearl River ◽  
The Pearl River Delta ◽  
Mobile Emissions ◽  
The Pearl River ◽  
Emission Ratios

Abstract. Semi-volatile and intermediate-volatility organic compounds (S–IVOCs) are considered critical precursors of secondary organic aerosol (SOA), which is an important component of fine particulate matter (PM2.5). However, knowledge of the contributions of S–IVOCs to SOA is still lacking in the Pearl River Delta (PRD) region, southern China. Therefore, in this study, an emission inventory of S–IVOCs in the PRD region was developed for the first time for the year 2010. The S–IVOC emissions were calculated based on a parameterization method involving the emission factors of POA (primary organic aerosol), emission ratios of S–IVOCs to POA, and domestic activity data. The total emissions of S–IVOCs were estimated to be 323.4 Gg, with major emissions from central cities in the PRD, i.e., Guangzhou, Foshan, and Shenzhen. On-road mobile sources and industries were the two major contributors of S–IVOC emissions, with contributions of ∼42 % and ∼35 %, respectively. Furthermore, uncertainties of the emission inventory were evaluated through Monte Carlo simulation. The uncertainties ranged from −79 % to 229 %, which could be mainly attributed to mass fractions of OC (organic carbon) to PM2.5 from on-road mobile emissions and emission ratios of IVOCs ∕ POA. The developed S–IVOC emission inventory was further incorporated into the Weather Research and Forecasting with Chemistry (WRF-Chem) model with a volatility basis-set (VBS) approach to improve the performance of SOA simulation and to evaluate the influence of S–IVOCs on SOA formation at a receptor site (Wan Qing Sha (WQS) site) in the PRD. The following results could be obtained. (1) The model could resolve about 34 % on average of observed SOA concentrations at WQS after considering the emissions of S–IVOCs, and 18 %–77 % with the uncertainties of the S–IVOC emission inventory considered. (2) The simulated SOA over the PRD region was increased by 161 % with the input of S–IVOC emissions, and it could be decreased to 126 % after the reaction coefficient of S–IVOCs with OH radical was improved. (3) Among all anthropogenic sources of S–IVOCs, industrial emission was the most significant contributor of S–IVOCs for SOA formation, followed by on-road mobile, dust, biomass burning, residential, and off-road mobile emissions. Overall, this study firstly quantified emissions of S–IVOCs and evaluated their roles in SOA formation over the PRD, which contributes towards significantly improving SOA simulation and better understanding of SOA formation mechanisms in the PRD and other regions in China.

scholarly journals Emission inventory of semi-volatile and intermediate volatility organic compounds and theireffectson SOA over the Pearl River Delta region

2019 ◽  
Author(s):  
Liqing Wu ◽  
Xuemei Wang ◽  
Sihua Lu ◽  
Min Shao ◽  
Zhenhao Ling
Keyword(s):  
Organic Compounds ◽  
Pearl River Delta ◽  
Emission Inventory ◽  
Organic Aerosol ◽  
River Delta ◽  
Pearl River ◽  
The Pearl River Delta ◽  
Mobile Emissions ◽  
The Pearl River ◽  
Emission Ratios

Abstract. Semi-volatile and intermediate volatility organic compounds (S/IVOCs) are considered as critical precursors of secondary organic aerosol (SOA), which is an important component of fine particulate matter (PM2.5). However, the knowledge on the contributions of S/IVOCs to SOA is still poorly understood in the Pearl River Delta (PRD) region, southern China. Therefore, in this study, an emission inventory of S/IVOCs in the Pearl River Delta (PRD) region was developed for the first time for the year 2010. The S/IVOCs emission was calculated based on a parameterization method involving the emissions factors of POA (primary organic aerosol), emission ratios of S/IVOCs to POA, and domestic activity data. The total emission of S/IVOCs was estimated to be 323.4 Gg, with major emissions from central cities in PRD, i.e., Guangzhou, Foshan, and Shenzhen. On-road mobile sources and industries were the two major contributors of S/IVOC emissions, with contributions of ~ 42 % and ~ 35 %, respectively. Furthermore, uncertainties of the emission inventory were evaluated through Monte Carlo simulation. The uncertainties ranged from −79 % to 229 %, which could be mainly attributed to mass fractions of OC (organic compound) to PM2.5 from on-road mobile emissions and emission ratios of IVOCs/POA. The developed S/IVOC emission inventory was further incorporated into the Weather Research and Forecasting with Chemistry (WRF-Chem) model with a volatility basis-set (VBS) approach to improve the performance of SOA simulation and to evaluate the influence of S/IVOCs on SOA formation at a receptor site (Wan Qing Sha (WQS) site) of PRD. The following results could be obtained: (1) The model could resolve about 34 % on average of observed SOA concentrations at WQS after considering the emissions of S/IVOCs, and 18 %–77 % with the uncertainties of the S/IVOC emission inventory considered. (2) The simulated SOA over the PRD region was increased by 161 % with the input of S/IVOC emissions, and it could be decreased to 126 % after the reaction coefficient of S/IVOCs with OH radical was improved. (3) Among all anthropogenic sources of S/IVOCs, industrial emission was the most significant contributor of S/IVOCs for SOA formation, followed by on-road mobile, dust, biomass burning, residential, and off-road mobile emissions. Overall, this study firstly quantified emissions of S/IVOCs and evaluated their roles in SOA formation over PRD, which contribute towards significantly improving SOA simulation and better understanding of SOA formation mechanisms in PRD and other regions in China.

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

2019 ◽  
Vol 19 (22) ◽  
pp. 14403-14415 ◽  
Author(s):  
Yu-Qing Zhang ◽  
Duo-Hong Chen ◽  
Xiang Ding ◽  
Jun Li ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
River Delta ◽  
Pearl River ◽  
Anthropogenic Emissions ◽  
Anthropogenic Pollutants ◽  
The Pearl River Delta ◽  
The Pearl River ◽  
The Impact

Abstract. Secondary organic aerosol (SOA) formation from biogenic precursors is affected by anthropogenic emissions, which are not well understood in polluted areas. In this study, we accomplished a year-round campaign at nine sites in polluted areas located in the Pearl River Delta (PRD) region during 2015. We measured typical biogenic SOA (BSOA) tracers from isoprene, monoterpenes, and β-caryophyllene, as well as major gaseous and particulate pollutants and investigated the impact of anthropogenic pollutants on BSOA formation. The concentrations of BSOA tracers were in the range of 45.4 to 109 ng m−3 with the majority composed of products from monoterpenes (SOAM, 47.2±9.29 ng m−3), isoprene (SOAI, 23.1±10.8 ng m−3), and β-caryophyllene (SOAC, 3.85±1.75 ng m−3). We found that atmospheric oxidants, Ox (O3 plus NO2), and sulfate correlated well with later-generation SOAM tracers, but this was not the case for first-generation SOAM products. This suggested that high Ox and sulfate levels could promote the formation of later-generation SOAM products, which probably led to the relatively aged SOAM that we observed in the PRD. For the SOAI tracers, both 2-methylglyceric acid (NO/NO2-channel product) and the ratio of 2-methylglyceric acid to 2-methyltetrols (HO2-channel products) exhibit NOx dependence, indicating the significant impact of NOx on SOAI formation pathways. The SOAC tracer was elevated in winter at all sites and was positively correlated with levoglucosan, Ox, and sulfate. Thus, the unexpected increase in SOAC in wintertime might be highly associated with the enhancement of biomass burning, O3 chemistry, and the sulfate component in the PRD. The BSOAs that were estimated using the SOA tracer approach showed the highest concentration in fall and the lowest concentration in spring with an annual average concentration of 1.68±0.40 µg m−3. SOAM dominated the BSOA mass all year round. We also found that BSOA correlated well with sulfate and Ox. This implied a significant effect from anthropogenic pollutants on BSOA formation and highlighted that we could reduce BSOA by controlling the anthropogenic emissions of sulfate and Ox precursors in polluted regions.

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