Ambient nitrogen dioxide pollution and spreadability of COVID-19 in Chinese cities

This study aims to explore the relationship between ambient NO₂ levels and the transmission ability (basic reproductive number, R₀) of COVID-19 in 63 Chinese cities. After adjustment for temperature and relative humidity, R₀ was positively associated with NO₂ concentration at city level. The temporal analysis within Hubei province indicated that all the 11 Hubei cities (except Xianning City) had significant positive correlations between NO₂ concentration (with 12-day time lag) and R₀ (r > 0.51, p < 0.005). Since the association between ambient NO₂ and R₀ indicated NO₂ may increase underlying risk of infection in the transmission process of COVID-19. In addition, NO₂ is also an indicator of traffic-related air pollution, the association between NO₂ and COVID-19's spreadability suggest that reduced population movement may have reduced the spread of the SARS-CoV-2.