Impact of Inter-Regional Transport in a Low-Emission Scenario on PM2.5 in Hubei Province, Central China

Abstract

In 2020, when the novel coronavirus disease 2019 (COVID-19) broke out as a global pandemic, cities in Hubei Province first went into lockdown on 23 January and resumed work and production on 20 March. From February to March 2020, human activities in Hubei decreased significantly, with the average particulate matter smaller than 2.5 μm (PM2.5) concentration standing at 40 μg/m3, which is 21% lower than the expected based on a linear fitting trend in thePM2.5 concentration in Hubei. By using the empirical orthogonal function (EOF) method, this paper comparatively analyzes the spatial-temporal variations of Hubei’s PM2.5 concentration anomaly in February and March 2020 and the same periods of 2016–2019. The results show that the daytime peak of the PM2.5 daily variation in Hubei in a low-emission scenario during COVID-19 declined significantly, to which human activities contributed the most. However, during nighttime, the PM2.5 peak became more prominent, and the meteorological conditions had a more noticeable effect on the PM2.5 concentration. In addition, during COVID-19, there was a great drop in PM2.5 pollution accumulated from local sources within the urban circle of Wuhan City, while an increase was seen in central-western Hubei due to the inter-regional pollutant transport. Thus, the high PM2.5 concentration center in the urban circle of Wuhan disappeared, but the pollution transport channel cities in central-western Hubei remained as high-PM2.5-concentration centers.

Two Typical Patterns of Regional PM2.5 Transport for Heavy Air Pollution Over Central China: Rapid Transit Transport and Stationary Accumulation Transport

“…Regional transport plays a significant role in the formation and evolution of air pollution episodes, as well as the air quality over the receptor regions (Xiong et al, 2021;Bai et al, 2022;Shen et al, 2022). The measured concentrations of particulate matter in the metropolitan areas of South America have been caused predominantly by long-range transport (Diaz Resquin et al, 2018).…”

Characteristics of PM2.5 Chemical Species in 23 Chinese Cities Identified Using a Vehicular Platform

“…To combat this issue, China implemented stringent air pollution prevention and control measures from 2013 onwards, resulting in a significant 32% reduction in the nationwide average annual concentration of PM 2.5 within five years [4]. Despite these efforts, ongoing research has continued to report instances of pollution, suggesting that the existing measures have not entirely curbed PM 2.5 pollution in China [5][6][7]. Studies, such as the model analysis by Wang et al [8], have highlighted that substantial reductions in emissions from transportation and industrial production were insufficient to prevent haze pollution, particularly during unfavorable weather conditions in winter.…”