College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
Sci Total Environ. 2021 Sep 20;788:147795. doi: 10.1016/j.scitotenv.2021.147795. Epub 2021 May 15.
Real-world vehicle emission factors (EFs) for the total intermediate volatile organic compounds (total-IVOCs) and volatile organic compounds (VOCs) from mixed fleets of vehicles were quantified in the Yangtze tunnel in Shanghai. Relationships of EFs of IVOCs with fleet compositions and vehicle speed as well as secondary organic formation potentials (SOAFPs) from IVOCs and VOCs were studied. Multiple linear regression (MLR) was used to estimate EFs of total-IVOCs for gasoline and diesel vehicles. IVOCs were classified into unresolved complex mixtures (unspeciated cyclic compounds and branched alkanes (b-alkanes)) and speciated targets (11 n-alkanes and ten polycyclic aromatic hydrocarbons (PAHs)). The results showed that the average EF of total-IVOCs was 24.9 ± 7.8 mg/(km·veh), which was comparable to that of VOCs. Unspeciated cyclic compounds and b-alkanes dominated the main composition (77% and ~19%), followed by n-alkanes (4%) and PAHs (~1%). EFs of IVOCs showed a significant, positive relationship with diesel vehicle fractions (p < 0.05). EFs of IVOCs dropped notably with the decrease of the diesel vehicle fractions. SOAFP produced by the total organic compounds (IVOCs + VOCs) was 8.9 ± 2.5 mg/(km·veh), in which up to 86% of SOAFP was from IVOCs. Estimated EFs of total-IVOCs for gasoline vehicles and diesel vehicles were 15.3 and 219.8 mg/(km·veh) respectively. Our results demonstrate that IVOCs emitted from diesel vehicles are the main emission sources under real world conditions and significant contributions of IVOCs emissions to SOA formation is evident, which indicates the necessity of making control policies to reduce IVOCs emissions from vehicles.
在上海的长江隧道中，量化了混合车队的总中间挥发性有机化合物 (总-IVOC) 和挥发性有机化合物 (VOC) 的实际车辆排放因子 (EF)。研究了 IVOCs 的 EF 与车队组成、车辆速度的关系以及 IVOCs 和 VOCs 的二次有机形成潜力 (SOAFP)。多元线性回归 (MLR) 用于估算汽油和柴油车的总-IVOCs EF。将 IVOCs 分为未解析的复杂混合物 (未指定的环状化合物和支链烷烃 (b-烷烃)) 和指定的目标 (11 个正构烷烃和十个多环芳烃 (PAHs))。结果表明，总-IVOCs 的平均 EF 为 24.9 ± 7.8 mg/(km·veh)，与 VOCs 相当。未解析的环状化合物和 b-烷烃占主要成分 (77%和 ~19%)，其次是正构烷烃 (4%)和 PAHs (~1%)。IVOCs 的 EF 与柴油车比例呈显著正相关 (p < 0.05)。随着柴油车比例的降低，IVOCs 的 EF 明显下降。总有机化合物 (IVOCs + VOCs) 产生的 SOAFP 为 8.9 ± 2.5 mg/(km·veh)，其中高达 86%的 SOAFP 来自 IVOCs。估算的汽油车和柴油车总-IVOCs EF 分别为 15.3 和 219.8 mg/(km·veh)。我们的结果表明，在实际情况下，柴油车排放的 IVOCs 是主要的排放源，IVOCs 排放对 SOA 形成的贡献显著，这表明有必要制定控制政策来减少车辆的 IVOCs 排放。
