Abstract:
This study investigates Particulate Matter (PM) variations in Kochi, India, and its association with meteorological variables by analyzing five years of ground-based observational data. It focuses on PM pollution at the Vyttila Mobility Hub, using the hourly mean of PM2.5 and PM10 data from January 2018 to March 2023. Annual PM2.5, 41.78 μg/m3 and PM10, 76.64 μg/m3 levels exceeded Indian National Ambient Air Quality Standards and World Health Organization limits, notably in winter and post-monsoon seasons. Inter-annual trends showed a decline from 2018 to 2021, followed by a rise in 2022, with the most significant decline observed between 2019 and 2020 possibly due to COVID-19 restrictions. Monthly variations revealed elevated PM levels in winter and lower levels during the monsoon months. Sunday consistently recorded the lowest levels in the weekly analysis. Diurnal patterns displayed two peaks during morning and evening rush hours. Additionally, the study included an examination of ratios across different time periods. Winter’s higher PM2.5/PM10 (0.65 ± 0.12) ratio indicated combustion emissions, while the monsoon’s lower ratio, (0.47 ± 0.15) resulted from rainout. Correlation analysis of PM and meteorological variables showed temperature positively correlates with PM, while humidity and wind speed negatively correlate. Fire at the Brahmapuram solid waste treatment plant in March 2023 led to elevated emissions, resulting in a surge of around 78% in PM2.5 and 15% in PM10 compared to the mean value of previous years and the observed ratio was 0.65 ± 0.15, indicating the increased presence of PM2.5 due to the fire incident.
2025- Aerosol Science and Engineering