Impact of Circular, Waste-Heat Reuse Pathways on PM_2.5-Air Quality, CO₂ Emissions, and Human Health in India: Comparison with Material Exchange Potential

Abstract

India is home to 1.3 billion people who are exposed to some of the highest levels of ambient air pollution in the world. In addition, India is one of the fastest-growing carbon-emitting countries. Here, we assess how two strategies to reuse waste-heat from coal-fired power plants and other large sources would impact PM 2.5 -air quality, human health, and CO 2 emissions in 2015 and a future year, 2050, using varying levels of policy adoption (current regulations, proposed single-sector policies, and ambitious single-sector strategies). We find that power plant and industrial waste-heat reuse as input to district heating systems (DHSs), a novel, multisector strategy to reduce local biomass burning for heating emissions, can offset 71.3–85.2% of residential heating demand in communities near a power plant (9.3–12.4% of the nationwide heating demand) with the highest benefits observed during winter months in areas with collocated industrial activity and higher residential heating demands (e.g., New Delhi). Utilizing waste-heat to generate electricity via organic Rankine cycles (ORCs) can generate an additional 22 (11% of total coal-fired generating capacity), 41 (8%), 32 (13%), and 6 (5%) GW of electricity capacity in the 2015, 2050-current regulations, 2050-single-sector, and 2050-ambitious-single-sector scenarios, respectively. Emission estimates utilizing these strategies were input to the GEOS-Chem model, and population-weighted, simulated PM 2.5 showed small improvements in the DHS (0.2–0.4%) and ORC (0.3–3.4%) scenarios, where the minimal DHS PM 2.5 -benefit is attributed to the small contribution of biomass burning for heating to nationwide PM 2.5 emissions (much of the biomass burning activity is for cooking). The PM 2.5 reductions lead to ∼130–36,000 mortalities per year avoided among the scenarios, with the largest health benefits observed in the ORC scenarios. Nationwide CO 2 emissions reduced <0.04% by DHSs but showed larger reductions using ORCs (1.9–7.4%). Coal fly-ash as material exchange in cement and brick production was assessed, and capacity exists to completely reutilize unused fly-ash toward cement and brick production in each of the scenarios.

PM2.5 exposures increased for the majority of Indians and a third of the global population during COVID-19 lockdowns: a residential biomass burning and environmental justice perspective

“…In addition, residential biomass burning for cooking and heating has exacerbated PM 2.5 exposure disparities in non-lockdown times throughout India [31,34]-with most of the burden on women and rural populations that use biomass as cooking fuel. Surprisingly, during the COVID-19 lockdown when families of similar strata were confined to presumably similar indoor environments, exposure disparities persisted, both in terms of actual PM 2.5 exposures as well as increases from baseline exposures.…”

“…5 exposure studies [29,30]) that incorporates uncertainties/distributions from both microenvironment PM 2.5 concentrations and the 24 h recall surveys to estimate average PM 2.5 exposures and 95% distributions for each Indian state's subpopulation groups (e.g. urban/rural, gender, and age; see SI section 1 for a detailed example of this framework for rural Uttar Pradesh women aged [30][31][32][33][34][35]. The PM 2.5 exposure approach outlined here assumes all urban or rural populations in a state have the same ambient exposure distribution for all outdoor activities, respectively, which has inherent misclassification errors, particularly considering the wide range of PM 2.5 concentrations observed in Indian cities at such fine scales [31].…”