Iranian Journal of Geophysics

Iranian Journal of Geophysics

Effects of meteorological factors and air pollution on the spread and transmission patterns of COVID-19 in Iran

Document Type : Research Article

Authors
Farahnaz FazelRastgar 1
Sakineh Khansalari 2
Venkataraman Sivakumar 3
1 Ph.D., Discipline of Physics, School of Chemistry and Physics, University of KwaZulu-Natal, South Africa
2 Assistant Professor, Research Institute of Meteorology and Atmospheric Science, Tehran, Iran
3 Professor, S. V. Raman Researchers Roadmap, Westville, South Africa
10.30499/ijg.2025.486036.1647
Abstract
This study investigates the understanding meteorological and environmental drivers of COVID-19 transmission in Iran. This work examines multiple datasets and models obtained from NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) database and ERA5 hourly data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The study underscores the critical role of meteorological factors in the transmission dynamics of COVID-19, emphasizing the interplay of wind patterns, atmospheric levels, and humidity. Wind speeds at 10 meters and 850 hPa show strong positive correlations with transmission risk (correlation coefficients: 0.76 and 0.75). This suggests that stronger surface winds may facilitate the airborne spread of viral particles. Conversely, reduced wind speeds at 700 and 500 hPa show significant negative correlations (-0.53 and -0.70), highlighting how atmospheric stratification affects virus dispersion. Also, this work shows a negative correlation exists between relative humidity and COVID-19 transmission. Higher humidity may suppress the virus's airborne viability or dispersal, emphasizing the need for effective ventilation, especially in low-humidity indoor environments.
    The study also observed a notable increase in air pollutants—specifically, NO2, Pm2.5, SO2, and low-level ozone—during the fifth COVID-19 wave. This is in comparison with short pre- and post-events of the peak wave, despite lockdown measures. This caused the pollution accumulation without ventilation due to the specific stable weather. This rise in pollutants highlights the intersection of public health challenges posed by both viruses spread and air quality. The study also noted an expected increase in ozone levels during the summer months of the fifth wave, attributed to high temperatures that generally foster ozone formation. However, the analysis suggests that temperature alone does not significantly influence COVID-19 transmission risk, highlighting the complex role of multiple variables in influencing the spread of virus. Additionally, in the stable atmospheric conditions of the middle and upper levels during hot summer months, both ozone and particulate matter pollution correlated positively with transmission risk. This relationship was especially evident under unusually high temperatures (0.57K above normal) and hazy conditions characterized by increased aerosol optical depth (AOD) in August 2021.
Keywords
Air pollution
COVID-19
Iran
meteorological factors

Subjects

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Iranian Journal of Geophysics
Volume 19, Issue 6
January and February 2026
Pages 105-123