Dr. Chandan Sarangi
IIT Madras
Impact of regional aerosol transport from North India on PM2.5 of Chennai during Winter
ABSTRACT
Over the past decade, Southern peninsular India has become increasingly susceptible to air pollution, particularly in its urban regions, largely attributable to urbanization and industrial expansion. Also, the long-range transport of regional air pollutants from North to South India is enhancing during the winter months inducing severe haze condition over relatively cleaner eastern coast and south Indian environments. This study examines the macro-physical properties of transported haze plumes reaching Chennai, a tropical coastal area in the south India, especially during January and February months. We will use collocated measurements of vertical aerosol measurements from Micro Pulse Lidar (MPL), satellite observations and in situ air quality observations over Chennai. Composite analysis of hazy and non-hazy period are segregated using the aerosol optical depth (AOD) observed above the atmospheric boundary layer (ABL) using continuous MPL observations. The hazy days are observed to >70% of the observation duration and they are closely associated with the sea breeze effect over Chennai. Moreover, we observe a ~1 hr lag in the sea breeze onset between hazy and non-hazy days. Interestingly, the ABL-Height during the hazy days is observed to be ~0.5 km shallower during the hazy days and, it intensity of the impact is maximum (change in ABL >1 km) after the sunset. As a consequent, the night-time magnitude of surface pollution (PM2.5) shows a substantial increase (~30%) during hazy days as compared to the non-hazy days. Our finding suggests that the regional aerosol transport could play a substantial role in the observed recent enhancement in PM2.5 in Eastern and Southern Indian megacities.
ABOUT THE SPEAKER
Chandan Sarangi is an Assistant Professor at the Department of Civil Engineering, IIT Madras, Chennai, Tamil Nadu, India. He completed his Post Doctorate Research from the Pacific Northwest National Laboratory (PNNL), Richland, WA, USA, and Integrated Ph.D. from IIT Kanpur, India. He has extensive experience in Aerosol-cloud-climate interactions; Impact of climate change on Cloud systems and rainfall; Impact of aerosols on Evapotranspiration and land-atmosphere interactions; Effect of dust deposition on snow darkening and Himalayan glaciers; Urban heat island effect and air quality over megacities; Extreme rainfall and coupling with aerosols and urbanization, and Cloud seeding research. He has been part of many cutting edge research teams and have published first author papers in many reputed and high impact journals like Nature Communications, Nature Climate Change, NPJ Climatic and Atmospheric Sciences, Geophysical Research Letters, Atmospheric Chemistry and Physics etc. More details about him and his research work can be found at https://civil.iitm.ac.in/faculty/chandansarangi/
