Increasing Potential for Air Pollution over Megacity New Delhi: A Study Based on 2016 Diwali Episode

Tanmoy Mukherjee,Satyendra K. Pandey,Acharya Asutosh,Lian Yang,Annu Panwar,Partha P. Gogoi,V. Vinoj

doi:10.4209/aaqr.2017.11.0440

Tanmoy Mukherjee, Satyendra K. Pandey + Show 5 more

Open Access

https://doi.org/10.4209/aaqr.2017.11.0440

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Abstract

Air pollution over the megacity New Delhi has gained significant attention in recent times. Local pollution, along with advection from upwind sources, long-range transport and festivities (e.g., Diwali) contributing large emissions from firecrackers, has led to high loading conditions over the city. In this study, we assess a particulate pollutant event that coincided with the festival of Diwali in 2016 using multiple parameters related to particulate pollution from the ground and satellite based measurements in relation to the observed climatology during the period of 2000 to 2016. Our analysis reveals that the episode of severe air pollution in 2016 was exacerbated by the long-range transport of absorbing fine aerosols emanating from biomass/stubble burning in the adjacent states to the northwest of National Capital Territory (NCT) of India. Based on concentration weighted trajectory (CWT) analysis using the PM2.5 mass concentration and AOD, the high loading conditions were related to trajectories that passed through the northwest of NCT. The period after Diwali in 2016 also coincided with air masses traversing large biomass burning areas. The long-term changes in the fire counts indicate that these events have been increasing at an alarming rate of ~25% per year since 2000, creating the potential for high particulate pollution over downwind cities such as Delhi.

Highlights

The degradation of air quality and frequent heavy pollution events in urban agglomerations have become a major concern in the recent times
Our analysis reveals that the episode of severe air pollution in 2016 was exacerbated by the long-range transport of absorbing fine aerosols emanating from biomass/stubble burning in the adjacent states to the northwest of National Capital Territory (NCT) of India
Based on concentration weighted trajectory (CWT) analysis using the PM2.5 mass concentration and Aerosol Optical Depth (AOD), the high loading conditions were related to trajectories that passed through the northwest of NCT

Summary

Introduction

The degradation of air quality and frequent heavy pollution events in urban agglomerations have become a major concern in the recent times. To explore the contribution of the long-range transport, we utilized the HYSPLIT trajectories to carry out the concentration-weighted trajectory (CWT) analysis, which illustrate potential sources of high aerosol loading during the period around Diwali over New Delhi (Seibert et al, 1994; Hsu et al, 2003; Vinoj et al, 2010).

Results

Conclusion