为了控制COVID-19的传播,石家庄在2020年(封锁I)和2021年(封锁II)实施了两次不同程度的封锁。我们分析了空气质量指数(AQI)的变化,两次封锁和2019年同期的PM2.5、O3和VOC,并量化了封锁期间人为来源的影响。结果表明,AQI分别下降了13.2%和32.4%,在封锁I和封锁II期间,PM2.5浓度分别下降了12.9%和42.4%,分别,由于城市交通流动性和工业活动水平的下降。然而,突然和不合理的减排导致O3浓度增加了160.6%和108.4%,分别,在封锁期间。探讨O3浪涌的原因,分别研究了主要前驱体NOx和VOCs,并确定了在封锁期间影响臭氧形成的主要VOCs种类和VOCs的来源变化,值得注意的是,在封锁期间,VOCs的日变化特征与烹饪之间的关系变得明显。这些发现表明,可以通过限制产量来改善区域空气质量,但是应该注意由不合理的减排引起的O3激增,明确城市O3管理的控制重点。
To control the spread of COVID-19, Shijiazhuang implemented two lockdowns of different magnitudes in 2020 (lockdown I) and 2021 (lockdown II). We analyzed the changes in air quality index (AQI), PM2.5,
O3, and VOCs during the two lockdowns and the same period in 2019 and quantified the effects of anthropogenic sources during the lockdowns. The results show that AQI decreased by 13.2% and 32.4%, and PM2.5 concentrations decreased by 12.9% and 42.4% during lockdown I and lockdown II, respectively, due to the decrease in urban traffic mobility and industrial activity levels. However, the sudden and unreasonable emission reductions led to an increase in
O3 concentrations by 160.6% and 108.4%, respectively, during the lockdown period. To explore the causes of the
O3 surge, the major precursors NOx and VOCs were studied separately, and the main VOCs species affecting ozone formation during the lockdown period and the source variation of VOCs were identified, and it is important to note that the relationship between diurnal variation characteristics of VOCs and cooking became apparent during the lockdown period. These findings suggest that regional air quality can be improved by limiting production, but attention should be paid to the surge of
O3 caused by unreasonable emission reductions, clarifying the control priorities for urban
O3 management.