Climatic controls on particulate matter in Campo Grande, Brazil: short-term variability

This study investigates the short-term variability of particulate matter (PM2.5 and PM10) concentrations and their modulation by meteorological conditions in Campo Grande, Brazil, from May to December 2021. Hourly and daily PM data were analysed alongside air temperature, relative humidity, wind speed, precipitation, atmospheric pressure, and solar radiation using descriptive statistics, correlation analysis, and multiple linear regression. Mean PM10 concentrations complied with Brazilian air quality standards (CONAMA) but frequently exceeded World Health Organization guidelines, indicating potential public health risks. Temperature showed a weak-to-moderate positive correlation with PM concentrations, whereas relative humidity exhibited a moderate negative correlation, highlighting its role in pollutant removal. Wind speed and precipitation showed weak, generally non-significant correlations, reflecting atmospheric stability and low ventilation. Seasonal analysis revealed higher PM levels during the dry season, associated with low humidity, scarce rainfall, and biomass burning, while rainy-season conditions favoured pollutant dispersion. The PM2.5/PM10 ratio averaged 0.44, indicating a mixed contribution of fine and coarse particles influenced by soil dust and biomass burning. Overall, the results emphasise that compliance with national standards does not necessarily ensure public health protection and reinforce the need for continuous air quality monitoring and regulatory alignment with international guidelines.