Study on associated effects of extreme drought and heatwave on air quality in South Africa during october 2022

Abstract This study investigates the impact of combined drought and extreme heatwave events on air quality in South Africa during October 2022 (study period). An analysis of meteorological data revealed a sharp increase in surface air temperature and a significant decrease in precipitation, resulting in an extreme heatwave and drought period. The Standardized Precipitation Evaporation Index (SPEI) for October 2022 showed an extreme drought value of -2.01, reflecting increased dryness over the past two decades. Meteorological analysis highlighted the influence of the intensified stationary Angola heat low and Botswana upper ridge subtropical high, facilitating dry and warm air advection into the region, exacerbating an extreme climatic situation with heatwave conditions. Ozone levels exceeded 80 ppb (unhealthy) in northern, central, and eastern regions, particularly on October 13, with concentrations ranging between 88.2 and 93 ppb. Long-term data (1980–2022) showed rising trends in PM2.5 and black carbon concentrations, peaking at 1.48 × 10⁻⁸ kg/m³ and 8 × 10⁻¹⁰ kg/m³ in October 2022, with the highest values in Free State Province. Additionally, the UV Aerosol Index (UVAI) showed significant growth over the last decade, with high values in October 2022, signaling worsening air quality and environmental health concerns. The findings emphasize the important need for mitigation measures to address the compounding effects of extreme weather on air quality and public health.