Sensitivity of Secondary Inorganic Aerosol Concentrations to Precursor Emissions and Inorganic Aerosol Modules in CAMx over Central Europe
Abstract
The Comprehensive Air Quality Model with Extensions version 6.50 (CAMx-v6.50) supports two inorganic aerosol modules (ISORROPIA and EQSAM4clim) that can be used to model partitioning of secondary inorganic aerosol (SIA) constituents between the gas and aerosol phases. In this work, we studied spatial and temporal impacts of using these two modules in CAMx-v6.50 runs on the seasonal surface concentrations of particulate ammonium (PNH4), nitrate (PNO3) and sulfate (PSO4) over Central Europe in the period between 2018-2019.
Comparison between simulations showed the smallest influence on PSO4 and good agreement between PNH4 concentrations in all seasons. For PNO3, the agreement between seasonal concentrations was also good with the exception of summer when the use of EQSAM4clim has led to a significant underestimation in some regions.
Based on comparison of surface concentrations obtained from the simulations to measurements, we performed other simulation (with invoked EQSAM4clim module) in which we used perturbed emissions of NH3 and NOx (except summer months, NH3/NOx emissions were decreased/increased by 50 %). Comparison of outputs from this simulation to measurements showed that the used emission perturbations lead mainly to the improvement of some monthly PNH4, PNO3, NH3 and NO2 concentrations.