Modeling Ultrafine Particles Near a Large, Commercial Airport Using High-Fidelity Aircraft Emission Inventories and Aircraft-Specific Aerosol Size Distribution with CMAQ

Abstract Aircraft are an important source of ultrafine particles (UFPs) near airports, yet their contributions remain poorly quantified in chemical transport models. We addressed limitations by integrating high-fidelity aircraft emissions inventories (AEIs) generated by the Aviation Environmental Design Tool (AEDT) and an aircraft-specific aerosol size distribution (ASASD) into the Community Multiscale Air Quality (CMAQ) model for Boston Logan International Airport (KBOS). We conducted simulations with three different approaches of AEIs for a winter and a summer month in 2017. We compared modeled ultrafine particle number concentrations (UFPNC) with measurements from seven field monitoring stations around KBOS. Without ASASD, CMAQ predicted negligible UFPNC aviation contributions for all three AEIs; however, incorporating ASASD with a high-fidelity AEI led to an estimate of the monthly average of aircraft-attributable UFPNCat up to 48.6% of total UFPNC. In addition, the combination of a high-fidelity AEI and ASASD improved agreement with observed UFPNC. Distinct seasonal behaviors were found, with particle emissions (non-volatile and volatile) dominating UFPNC enhancements during winter. Both directly emitted particles and SO2 driven nucleation led to ∼109.7% greater UFPNC during summer. Our findings highlight the importance of using AEIs that reflect aircraft movement and particle size characteristics for modeling UFP near airports.