Effects of air pollution and weather on the initial COVID‐19 outbreaks in United States, Italy, Spain, and China: A comparative study

Abstract

Contrasting effects have been identified in association of weather (temperature and humidity) and pollutant gases with COVID‐19 infection, which could be derived from the influence of lockdowns and season change. The influence of pollutant gases and climate during the initial phases of the pandemic, before the closures and the change of season in the northern hemisphere, is unknown. Here, we used a spatial‐temporal Bayesian zero‐inflated‐Poisson model to test for short‐term associations of weather and pollutant gases with the relative risk of COVID‐19 disease in China (first outbreak) and the countries with more cases during the initial pandemic (the United States, Spain and Italy), considering also the effects of season and lockdown. We found contrasting association between pollutant gases and COVID‐19 risk in the United States, Italy, and Spain, while in China it was negatively associated (except for SO 2 ). COVID‐19 risk was positively associated with specific humidity in all countries, while temperature presented a negative effect. Our findings showed that short‐term associations of air pollutants with COVID‐19 infection vary strongly between countries, while generalized effects of temperature (negative) and humidity (positive) with COVID‐19 was found. Our results show novel information about the influence of pollution and weather on the initial outbreaks, which contribute to unravel the mechanisms during the beginning of the pandemic.

Spatial and temporal epidemiology of SARS-CoV-2 virus lineages in Teesside, UK, in 2020: effects of socio-economic deprivation, weather, and lockdown on lineage dynamics

“…Our findings indicate that some weather variables affected the total positive tests across Teesside in 2020. We found positive tests were reduced by higher temperatures, in accordance with previous research (Ganslmeier et al, 2021; Alaniz et al, 2023; Nottmeyer et al, 2023). This is probably due to both indirect and direct mechanisms, as warmer weather encourages outdoor (rather than indoor) socialising and increased indoor ventilation, while also reducing transmissibility of the virus particles (Ganslmeier et al, 2021).…”

“…The relationship between COVID-19 infection and weather is also complex. Higher temperatures have been associated with a reduction in cases in many countries including the UK (Ganslmeier et al, 2021;Alaniz et al, 2023;Nottmeyer et al, 2023), though a minority of studies have reported a positive effect (Tan & Schultz, 2022). Increased rainfall effects are more uncertain due to less research focus, with a metaanalysis finding evidence of increased infections (Tan & Schultz, 2022), while other research detected no relationship (Ganslmeier et al, 2021).…”