School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China; Key Laboratory of Organic Compound Pollution Control Engineering (MOE), Shanghai University, Shanghai 200444, China.
School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China; Key Laboratory of Organic Compound Pollution Control Engineering (MOE), Shanghai University, Shanghai 200444, China.
Sci Total Environ. 2020 Aug 25;732:139282. doi: 10.1016/j.scitotenv.2020.139282. Epub 2020 May 11.
The outbreak of COVID-19 has spreaded rapidly across the world. To control the rapid dispersion of the virus, China has imposed national lockdown policies to practise social distancing. This has led to reduced human activities and hence primary air pollutant emissions, which caused improvement of air quality as a side-product. To investigate the air quality changes during the COVID-19 lockdown over the YRD Region, we apply the WRF-CAMx modelling system together with monitoring data to investigate the impact of human activity pattern changes on air quality. Results show that human activities were lowered significantly during the period: industrial operations, VKT, constructions in operation, etc. were significantly reduced, leading to lowered SO, NO, PM and VOCs emissions by approximately 16-26%, 29-47%, 27-46% and 37-57% during the Level I and Level II response periods respectively. These emission reduction has played a significant role in the improvement of air quality. Concentrations of PM, NO and SO decreased by 31.8%, 45.1% and 20.4% during the Level I period; and 33.2%, 27.2% and 7.6% during the Level II period compared with 2019. However, ozone did not show any reduction and increased greatly. Our results also show that even during the lockdown, with primary emissions reduction of 15%-61%, the daily average PM concentrations range between 15 and 79 μg m, which shows that background and residual pollutions are still high. Source apportionment results indicate that the residual pollution of PM comes from industry (32.2-61.1%), mobile (3.9-8.1%), dust (2.6-7.7%), residential sources (2.1-28.5%) in YRD and 14.0-28.6% contribution from long-range transport coming from northern China. This indicates that in spite of the extreme reductions in primary emissions, it cannot fully tackle the current air pollution. Re-organisation of the energy and industrial strategy together with trans-regional joint-control for a full long-term air pollution plan need to be further taken into account.
COVID-19 的爆发在全球迅速蔓延。为了控制病毒的快速传播，中国实施了全国封锁政策以实行社会隔离。这导致人类活动减少，从而主要空气污染物排放量减少，这是空气质量改善的副作用。为了研究 COVID-19 封锁期间长三角地区的空气质量变化，我们应用 WRF-CAMx 建模系统和监测数据来研究人类活动模式变化对空气质量的影响。结果表明，人类活动在封锁期间显著降低：工业运营、车辆交通量、运营中的建筑等均显著减少，导致 SO、NO、PM 和 VOCs 排放量在一级和二级响应期间分别降低了约 16-26%、29-47%、27-46%和 37-57%。这些减排在改善空气质量方面发挥了重要作用。PM、NO 和 SO 的浓度在一级响应期间分别降低了 31.8%、45.1%和 20.4%；在二级响应期间分别降低了 33.2%、27.2%和 7.6%，而 2019 年同期分别为 33.2%、27.2%和 7.6%。然而，臭氧并没有减少，反而大幅增加。我们的结果还表明，即使在封锁期间，主要排放减少了 15%-61%，每日平均 PM 浓度仍在 15-79μg/m 之间，这表明背景和残留污染仍然很高。来源分配结果表明，PM 的残留污染来自工业（32.2-61.1%）、移动源（3.9-8.1%）、扬尘（2.6-7.7%）、居民源（2.1-28.5%）和北方长距离传输（14.0-28.6%）。这表明，尽管主要排放物的排放量急剧减少，但仍不能完全解决当前的空气污染问题。需要进一步考虑重新组织能源和工业战略以及进行跨区域联合控制，以制定全面的长期空气污染计划。
