Impacts of COVID-19 on Air Quality through Traffic Reduction

Abstract

In 2020, the first case of COVID-19 was confirmed in Korea, and social distancing was implemented to prevent its spread. This reduced the movement of people, and changes in air quality were expected owing to reduced emissions. In the present paper, the impact of traffic volume change caused by COVID-19 on air quality in Seoul, Korea, is examined. Two regression analyses were performed using the generalized additive model (GAM), assuming a Gaussian distribution; the relationships between (1) the number of confirmed COVID-19 cases in 2020–2021 and the rate of change in the traffic volume in Seoul, and (2) the traffic volume and the rate of change in the air quality in Seoul from 2016 to 2019 were analyzed. The regression results show that traffic decreased by 0.00431% per COVID-19 case; when traffic fell by 1%, the PM10, PM2.5, CO, NO2, O3, and SO2 concentrations fell by 0.48%, 0.94%, 0.39%, 0.74%, 0.16%, and −0.01%, respectively. This mechanism accounts for air quality improvements in PM10, PM2.5, CO, NO2, and O3 in Seoul during 2020–2021. From these results, the majority of the reduction in pollutant concentrations in 2020–2021 appears to be the result of a long-term declining trend rather than COVID-19.

Evaluation of roadside air quality using deep learning models after the application of the diesel vehicle policy (Euro 6)

“…As can be seen, the observed concentrations of CO, NO 2 , PM 10 dramatically reduced in 2020, and the deviation between the observation and the RNN prediction in 2020 becomes − 6.2%, − 28.6%, and − 29.3% for CO, NO 2 , PM 10 . This can be mostly attributed to the lockdown measures applied during COVID-19 pandemic 51 , 52 . Except for 2020, the further decrease in the concentrations of air pollutants compared to the RNN prediction may be attributable to the environmental policies such as Euro 6.…”

Statistical Characteristics of Air Quality Index DAQx*-Specific Air Pollutants Differentiated by Types of Air Quality Monitoring Stations: A Case Study of Seoul, Republic of Korea

“…The study period was interesting because it included social distancing periods in Seoul in 2020 and 2021 (Table A5), which were mandated by the government of the Republic of Korea due to the COVID-19 pandemic [49]. The measures taken during these periods [50,51] mainly resulted in traffic reduction [52,53]. However, they did not have the extent of a complete lockdown.…”

“…The U type AQMSs showed clear annual cycles of NO 2 in all four years, whereas they were weaker for B type and hardly recognizable for R type AQMSs. Additionally, a slightly lower NO 2 level was observed in 2020 and 2021 than in 2018 and 2019 mainly because of the traffic reductions during social distancing periods [52,53]. Due to photochemical reactions with precursors, primarily nitrogen oxides and volatile organic compounds [26], in the presence of solar radiation [57], the maximum concentrations of the secondary air pollutant O3 were observed in the summer months, especially in June [69], whereas O3 concentrations were minimal in the winter months.…”

COVID-19 and Beyond: COVID-19 Interventions and Power Plant Emissions in the United States

“…Concurrent with the lockdowns, air quality was reported to have improved in many parts of the United States, although air quality changes differed by location. U.S.-based studies have identified certain sourcesin particular, mobile sources and wildfiresthat contributed to air pollution variability during the lockdown period and post-lockdown period in 2020. ,− However, based on the existing literature on air quality responses to the COVID-19 lockdown (Table S1), it is unclear the extent to which EGU emissions were impacted by mobility and economic changes associated with COVID-19 public health interventions. Since stationary EGUs remain a major contributor to air pollution and greenhouse gas emissions in the United States and previous work has linked mobile emissions changes due to mobility patterns, policymakers will benefit from an understanding of how EGU emissions changed with and after pandemic-initiated shifts.…”