Substantial reduction in vehicular PAH emissions and emerging roles of tire wear: Tunnel-test in Guangzhou (2014–2019)

IF 3.7 2区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Atmospheric Environment Pub Date : 2025-09-20 DOI:10.1016/j.atmosenv.2025.121558

Shaoxuan Xiao , Runqi Zhang , Xiaoyang Wang , Zhou Zhang , Wei Song , Yuanyuan Qin , Chenglei Pei , Duohong Chen , Yanli Zhang , Xinming Wang

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Abstract

Emissions of polycyclic aromatic hydrocarbons (PAHs) from on-road vehicle fleets were investigated through tunnel tests conducted in 2014 and 2019 in Guangzhou, China, to assess the impacts of upgraded vehicle emission standards and changing fleet composition. The emission factors of PM_2.5-bound PAHs (four-ring and above) significantly decreased by 76.4 %, from 45.22 to 10.66 μg km⁻¹ veh⁻¹ during this period. Although the diesel fleet share fell by ∼75 % from 13.0 % to 3.3 %, diesel vehicles remained the dominant source of PAHs, exhibiting emission factors 9–50 times higher than gasoline vehicles. Notably, emissions of some 5- and 6-ring PAHs declined much less and even increased, suggesting that non-exhaust emissions, particularly tire wear, have become increasingly significant sources of PAHs. The overall toxicity, expressed in terms of toxic equivalency quotients (TEQ_BaP), declined by 66.7 %, yet benzo[a]pyrene consistently dominated total toxicity (69–74 %). Persistent nocturnal emission risks associated with diesel-dominated freight traffic highlight the need for targeted emission control policies. These results reveal the effectiveness of stringent regulatory measures in reducing vehicle exhaust emissions and stress the emerging importance of mitigating non-exhaust emission sources in urban pollution control strategies.

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车辆多环芳烃排放大幅减少及轮胎磨损的新作用：广州隧道试验（2014-2019）

本研究于2014年和2019年在中国广州进行了公路车辆多环芳烃（PAHs）排放的隧道试验，以评估车辆排放标准升级和车队组成变化的影响。在此期间，pm2.5结合的多环芳烃（四环及以上）排放因子从45.22 μg km−1 veh−1下降到10.66 μg km−1，显著降低了76.4%。虽然柴油车的份额从13.0%下降到3.3%，下降了约75%，但柴油车仍然是多环芳烃的主要来源，其排放系数比汽油车高9-50倍。值得注意的是，一些5环和6环多环芳烃的排放量下降幅度较小，甚至有所增加，这表明非废气排放，特别是轮胎磨损，已成为越来越重要的多环芳烃来源。以毒性当量商数（TEQBaP）表示的总毒性下降了66.7%，但苯并[a]芘始终占总毒性的主导地位（69 - 74%）。与柴油主导的货运交通相关的持续夜间排放风险突出了有针对性的排放控制政策的必要性。这些结果揭示了严格的监管措施在减少汽车尾气排放方面的有效性，并强调了在城市污染控制策略中减少非尾气排放源的重要性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Atmospheric Environment 环境科学-环境科学

CiteScore

9.40

自引率

8.00%

发文量

458

审稿时长

53 days

期刊介绍： Atmospheric Environment has an open access mirror journal Atmospheric Environment: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. Atmospheric Environment is the international journal for scientists in different disciplines related to atmospheric composition and its impacts. The journal publishes scientific articles with atmospheric relevance of emissions and depositions of gaseous and particulate compounds, chemical processes and physical effects in the atmosphere, as well as impacts of the changing atmospheric composition on human health, air quality, climate change, and ecosystems.