Particulate matter concentrations and their association with COVID-19-related mortality in Mexico during June 2020 Saharan dust event

The present study evaluated the impact of Saharan dust event on particulate matter (PM: PM₁₀ and PM_2.5) concentrations by analyzing the daily average PM data between Saharan dust days (June 23–29, 2020) and non-Saharan dust days (June 15 to June 22 and June 30 to July 12, 2020) for four majorly affected regions in Mexico and by comparing with three major previous events (2015, 2018, and 2019). The results showed that PM₁₀ and PM_2.5 concentrations were 2–5 times higher during the Saharan dust event with the highest daily averages of 197 μg/m³ and 94 μg/m³, respectively, and exceeded the Mexican standard norm (NOM-020-SSA1-2014). When comparing with the previous Saharan dust episodes of 2015, 2018, and 2019, the levels of PM₁₀ and PM_2.5 considerably increased and more than doubled across Mexico. The correlation analysis revealed a positive association of PM levels with the number of daily COVID-19 cases and deaths during Saharan dust event. Furthermore, the human health risk assessment showed that the chronic daily intake and hazard quotient values incremented during Saharan dust days compared to non-Saharan days, indicating potential health effects and importance of taking necessary measures to ensure better air quality following the COVID-19 pandemic. Graphical abstract: [Figure not available: see fulltext.].