Long-term comparison of near-surface and columnar aerosols over two contrasting environments in peninsular India

Continuous measurements of the near-surface black carbon (BC) aerosol mass concentration and columnar spectral aerosol optical depth (AOD) have been analyzed over rural and urban regions of peninsular India for the period of five years (2014 – 2018). The goal of this study is to gain a better understanding of the BC aerosols caused by anthropogenic emissions by using ground-based measurements from two different regions at the same time. Both regions exhibit similar monthly variations, however, annually, the urban region emits 2.5 times more BC aerosols. We found that urban activities account for the majority of roughly 50% of BC contributions. In addition, on weekdays BC levels are 20% higher than on weekends in the urban region. Furthermore, BC peaks in the morning and late evening with urban having a higher magnitude compared to rural region. One of the interesting findings is that even though surface-based BC mass concentration is 60% lower in the rural region, the AOD was almost similar in both regions, which could be attributed to the presence of elevated aerosol layers.