Seasonal variations of particulate matter in two size fractions (PM2.5 and PM10) and their relationship with meteorological parameters in Lahore, Pakistan

Abstract

Air pollution is rising globally in megacities, due to the human population pressure index, expanding automotive industries, factories, and the burning of fossil fuels that have a detrimental influence on the climate and public health. The current research work explores the study of fine and coarse mode particulate matter (PM_2.5 and PM₁₀) and the impact of meteorological parameters such as temperature, pressure, relative humidity, rainfall, and wind speed in Lahore (Pakistan) during 2019. The value of PM_2.5 ranged from 11.55 to 187.77 μg m⁻³ with a mean value of 55.49 ± 32.85 μg m⁻³. Similarly, the value of PM₁₀ varied from 8.57 to 334.26 μg m⁻³, with an average value of 101.49 ± 60.78 μg m⁻³ during the study period. The coefficients of determination between PM_2.5 and PM₁₀ had higher values during autumn (R² = 63.88%), followed by R² = 57.84% (winter), R² = 27.25% (spring), and R² = 22.41% (summer), respectively. Regression of PM_2.5 and PM₁₀ with temperature shows a negative correlation during winter and autumn while a positive correlation was observed during spring and summer seasons. Similarly, PM_2.5 and PM₁₀ are positively correlated with pressure in all four seasons. Throughout all four seasons, relative humidity (RH) has a positive association with PM_2.5 and a negative correlation with PM₁₀. Similarly, in winter, summer, and fall, RF is found to have a negative correlation with both PM_2.5 and PM₁₀. Wind speed shows a negative correlation with both size fractions of PM during all seasons.