Abstract From May 21st to 31st, 2018, a truck driver strike greatly decreased all vehicle activity in Brazil. We evaluated the concentrations of criteria pollutants in seven different microenvironments during this period in the Sao Paulo Megacity. Results were evaluated by violin plots, the Kruskal-Wallis test and diurnal cycles, comparing the year 2018 to an average of 4 previous years. Primary pollutants (CO and NO) decreased by 50% in 2018, predominantly in roadside (RDS) locations. NO2, PM10, and PM2.5 did not decrease as much, suggesting the relevance of secondary reactions and other sources (ex: fires). Ozone increased significantly (about 30–50%), possibly due to favourable atmospheric conditions (solar radiation) and changes in the NOx/VOCs ratio caused by the decrease in NO. Our findings help to better assess the role of vehicular emissions and provide insights on the impacts of interruption of activities (ex: during lockdowns) over air quality in metropolitan environments.

中文翻译：

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卡车司机罢工对圣保罗空气污染水平的影响

摘要 2018 年 5 月 21 日至 31 日，卡车司机罢工使巴西所有车辆活动大幅减少。我们评估了圣保罗特大城市在此期间七个不同微环境中标准污染物的浓度。结果通过小提琴图、Kruskal-Wallis 测试和昼夜循环进行评估，将 2018 年与前 4 年的平均值进行比较。2018 年主要污染物（CO 和 NO）减少了 50%，主要集中在路边 (RDS) 位置。NO2、PM10 和 PM2.5 没有减少那么多，表明二次反应和其他来源（例如：火灾）的相关性。臭氧显着增加（约 30-50%），可能是由于有利的大气条件（太阳辐射）和 NOx/VOCs 比率的变化导致 NOx 减少。