Spatial-Temporal variability of particulate matter less than 2.5 micrometer(PM2.5)concentration in Byimana, Rubavu and Gicumbi

Abstract

For this research, data on PM2.5 concentrations were gathered from three distinct locations in chosen areas of Rwanda. The data collection spanned from 2019 to 2021. These collected data were utilized to examine the diurnal, seasonal, and day-of-the-week patterns of PM2.5 concentrations in chosen areas. The study also analyzed the influence of meteorological parameters on the variations in PM2.5 levels. Furthermore, the contribution of each area to the overall PM2.5 concentrations was also investigated. In both chosen areas, the diurnal patterns of PM2.5 showed higher concentrations during the nighttime compared to the daytime. This increase in nighttime concentration is primarily attributed to the accumulation of particles under inversion conditions and atmospheric stability. The lowest PM2.5 values were observed in the late afternoon in all three areas. Furthermore, the reduction in human activities during weekends resulted in notably lower PM2.5 concentrations on Saturday and Sunday, while higher concentrations were observed on the remaining weekdays, irrespective of the month or weather conditions. The seasonal variation analysis indicates that during the wet season, there is decrease in PM2.5 concentrations due to the combined effect of total rainfall and relative humidity. This reduction is a result of washout and wet deposition, leading to lower fine particle concentrations compared to the dry season