Volatile organic compounds (VOCs) play a vital role in the formation of photochemical smog and haze in large urban environments. Previous source apportionment studies have focused on the contribution of different sources to VOC concentration with a view to pinpointing the major culprits for effective emission mitigation. However, different VOC sources may have different ozone (O₃) and secondary organic aerosol (SOA) formation potentials. From a control perspective, it would be more rational to consider the role of individual VOC sources in secondary pollution; therefore, here, we propose a tiered source identification method that considers the formation potentials of O₃ and SOA, which we applied in Calgary, Alberta, a site under the influence of multiple competing VOC sources. The pollution characteristics, secondary pollutant formation potential, and geographical origin of VOC sources were investigated over a five-year period. Seven major sources were identified using the positive matrix factorization (PMF) model, among which vehicle exhausts and solid fuel combustion were the dominant VOC sources responsible for O₃ (60%) and SOA (63%) formation. Combustion of both liquid fuel (gasoline and diesel) and solid fuel (wood and coal) has exceeded the contribution of oil and gas production and become the top contributor to O₃ and aerosol pollution in Calgary. This finding is consistent with the significant reduction (32.2−99.8%) in oil and gas production in Calgary over the period of 2013−2017. The source apportionment results show that the primary VOC source has shifted from conventional oil and gas extraction to a mixture of vehicle exhausts and oil and gas extraction, indicating the effectiveness of emission control measures taken in the energy sectors. Moreover, regionally transported VOCs from combustion sources in southeastern British Columbia have greatly increased the VOC level and secondary pollutant formation in Calgary. To effectively alleviate secondary pollution problems, the performance of joint pollution control measures has been suggested by the governments of both Alberta and British Columbia. These findings reveal that the tiered source identification strategy combining the traditional receptor model with socioeconomic factors, emission inventory, and source region analysis is a robust and promising tool for the interpretation of source apportionment results and optimization of secondary pollution control.

在大城市环境中，挥发性有机化合物（VOC）在光化学烟雾和雾霾的形成中起着至关重要的作用。以前的污染源分配研究集中在不同源对VOC浓度的贡献上，目的是查明有效减排的主要根源。但是，不同的VOC源可能具有不同的臭氧（O ₃）和二次有机气溶胶（SOA）形成潜能。从控制的角度来看，考虑单个VOC来源在二次污染中的作用更为合理；因此，在这里，我们提出一种考虑O ₃形成潜力的分层源识别方法SOA，这是我们在阿尔伯塔省卡尔加里市（一个受多种VOC竞争源影响的站点）应用的。在五年内调查了VOC来源的污染特征，二次污染物形成潜力和地理来源。使用正矩阵分解（PMF）模型确定了七个主要来源，其中汽车尾气和固体燃料燃烧是造成O ₃（60％）和SOA（63％）形成的主要VOC来源。液体燃料（汽油和柴油）和固体燃料（木材和煤炭）的燃烧已经超过了石油和天然气的生产，成为O ₃的最大贡献者。和卡尔加里的气溶胶污染。这一发现与2013-2017年期间卡尔加里的油气产量显着减少（32.2−99.8％）相一致。排放源分配结果表明，主要的VOC排放源已从常规的石油和天然气提取转向了车辆废气和石油和天然气的混合提取，这表明在能源领域采取排放控制措施的有效性。此外，从不列颠哥伦比亚省东南部的燃烧源经区域运输的挥发性有机化合物大大增加了卡尔加里的挥发性有机化合物含量和二次污染物形成。为了有效缓解二次污染问题，艾伯塔省和不列颠哥伦比亚省政府都建议采取联合污染控制措施。