An Airshed Approach to Mitigating Extreme PM2.5 Levels in India

NEELDIP BARMAN, Lucas Rojas Mendoza, Yuzhou Wang, Srinidhi Balasubramanian, Julian Marshall, Joshua S. Apte, Chandra Venkataraman, Indian Institute of Technology Bombay

     Abstract Number: 132
     Working Group: Aerosol Exposure

Abstract
Ambient fine particulate air pollution (PM2.5) in India is linked to over 1 million annual premature deaths. The Indo-Gangetic Plain (IGP) is home to ~40% of the Indian population and is among the world’s most polluted regions due to an interplay of emissions, topography and synoptic meteorology. While India’s present air quality policy is strongly city-centric, some researchers and policymakers believe an “airshed”-based approach would be more appropriate and useful than the current city-focused approach.

Here, we exploit the PAVITRA (air Pollution mAnagement and interVentIon Tool foR IndiA) tool, which includes an emissions inventory, disaggregated into 19 economic sectors (SMoG-PAVITRA), and a reduced complexity model for South Asia (InMAP-PAVITRA), to identify dominant states and sectors and their contributions to extreme PM2.5 airsheds within the IGP. We identify and investigate three most-polluted airsheds (northwest-IGP, central-IGP and eastern-IGP) with very high annual PM2.5 concentrations ranging from 60 to 140 ug/m3.

Emissions from six states/union territories (Haryana, Delhi, Uttar Pradesh [UP], Bihar, West Bengal [WB] and Odisha) have the strongest influence on PM2.5 concentrations in the three most-polluted airsheds. PM2.5 concentrations in the northwest-IGP airshed are contributed by emissions from Haryana, Delhi and UP, while central-IGP airshed by Bihar, UP and WB and eastern-IGP by WB and Odisha. Across these influencing states/union territories, PM2.5 concentrations are strongly influenced by emissions from different sectors like residential (Bihar 60%; UP 40%; WB 35%), agriculture (Haryana 20%), diesel vehicles (Haryana 24%; Delhi 30%), energy generation (WB 19%) and MSME (Micro, Small and Medium Enterprises; WB 16%), which also indicate the need for different sectoral interventions for different airsheds. Overall, our findings suggest the need for multi-sector interventions and multi-state cooperation to ameliorate the extreme PM2.5 levels in these three airsheds. The work also identifies a portfolio of interventions that can help India to attain the first World Health Organization interim target of 35 ug/m3 in these extreme PM2.5 airsheds.