Work

Modeling the Air Quality Impacts of Future Energy Scenarios

Year: 2025

Type: article

Abstract: Despite significant improvements in U.S. air quality in recent decades, many areas still experience exceedances of air quality standards. As some states mitigate climate change impacts by reducing greenhouse gas (GHG) emissions, simultaneous reductions of co-emitted air pollutants are seen. Human-Earth system models simulate the evolving energy system under various technology and policy scenarios, including emissions estimates of GHGs and associated air pollutants. Assessing the air quality impacts of these emission changes with a chemistry-transport model (CTM) typically entails labor-intensive processing of emissions inputs. A method that simplifies this processing while preserving scientific detail has been developed, linking projected emissions from the Global Change Analysis Model with state-level resolution (GCAM-USA) to the Community Multiscale Air Quality (CMAQ) CTM. Its application here examines the impacts in 2050 on ambient ozone and particulate matter (PM2.5) of three energy scenarios: (i) a reference scenario continuing pre-2022 legislation on GHG and air pollutant emissions to 2050, (ii) state-level GHG mitigation and vehicle electrification targets, and (iii) nationwide GHG mitigation and vehicle electrification targets. The reference scenario shows widespread air quality improvements over 2015 in populated areas, from SO2 and NOx emissions reductions of > 50% in fossil-fueled electricity, and > 80% in onroad NOx, with further improvements in the targeted mitigation scenarios. However, PM2.5 increases from increased wood heating driven by fuel prices, and in regions and sectors using carbon capture and storage for GHG mitigation. Overall, our approach facilitates efficient assessment of multiple energy scenarios without reducing complexity in the atmospheric process representations.

Source: ACS ES&T Air

DOI: 10.1021/acsestair.5c00175