出版社:Chinese Association for Aerosol Research in Taiwan
摘要:The concentration of PM2.5 in Delhi, one of the most polluted capital cities globally, frequently exceeds the Indian National Ambient Air Quality Standards, especially during the post-monsoon and winter months. This study evaluates the changes in PM2.5 concentrations across Delhi using a one way coupled model (WRF-CMAQ-AERMOD) for various hotspot-specific intervention scenarios during post-monsoon and winter of 2018. PM2.5 concentrations reduced up to 15% by scaling down total emissions across Delhi by 20%. An additional 9% reduction across entire Delhi and ~28% reduction at the top ten observation-based hotspots could be achieved if emissions of industry, unpaved road dust and construction in selected emission hotspots are made zero. Non-local contribution in hotspots of the city varied significantly. For example, the difference in the reductions of PM2.5 concentrations from citywide versus hotspot-specific interventions is estimated to be 28% at DU North Campus and 11% at Anand Vihar. An average reduction of 12% was computed when construction and MSW burning emissions were down sized 100% in the locations identified based on compliance complaints received at the Central Pollution Control Board’s online complaint portal. A marginal reduction of 4% estimated for the previously implemented traffic rationing measure, the odd-even rule, indicates that such regulation of vehicles alone might be inefficacious. The results suggest that stakeholders must focus on—(a) source and hotspot-specific interventions alongside city wide interventions to significantly reduce ambient PM2.5 concentrations, (b) local and non-local contributions from regions outside the hotspot grid needs to be carefully considered for estimating efficacy of an action plan.