A study on the trends and seasonal fluctuations of black carbon aerosols in the elevated region of Ooty, Western Ghats, Tamil Nadu, India

The accelerating effects of climate change, driven by rising greenhouse gas emissions, necessitate identifying key contributors like aerosols, mainly black carbon (BC), due to their significant impact on global warming. This study investigates the temporal and seasonal dynamics of BC aerosols in Ooty, Tamil Nadu, India, using a decade (2013–2023) of data from an Aethalometer. Annual BC concentrations varied from 0.51 µg/m³ (2020) to 1.1 µg/m³ (2023), with a decadal mean of 0.75 ± 0.26 µg/m³. Distinct season al variations were observed, with summer BC concentrations ranging from 0.9 to 1.6 µg/m³ (mean: 1.3 µg/m³) and monsoon values significantly lower at 0.2–0.5 µg/m³ (mean: 0.4 µg/m³). Winter exhibited a seasonal mean of 1.1 µg/m³, while post-monsoon BC concentrations averaged 0.6 µg/m³. Temperature (20–28.6°C), relative humidity (49–93%), and rainfall (0.4 7.81 mm/day) influenced the observed trends. April consistently showed peak BC levels (up to 1.87 µg/m³), while 2020 recorded the lowest due to reduced emissions. Seasonal trends revealed increasing BC levels from December to April, declining during the monsoon months (June–November). These findings underscore the need for sustained monitoring and mitigation strategies in high-altitude regions to address BCs’ climatic impacts, aiding global efforts against climate change.