Substantial NO_x emission mitigation is a relatively feasible and operable measure to synergistic control particle matter and ozone (O₃) pollution. Numerous works have shown that the parameterization of heterogeneous HONO formation increases both the simulated value of secondary nonorganic aerosol (SNA) and that of O₃. Adding the HONO heterogeneous reactions into air quality model inevitably leads to changes in the estimated benefits of NO_x abatement. We investigated the changes of SNA and O₃ concentrations to NO_x emission reduction before and after adding HONO heterogeneous reactions in the Community Multi-Scale Air Quality (CMAQ) model. Including HONO heterogeneous reactions in the simulation improved the benefits of NO_x reduction in SNA control in winter. With 80% NO_x reduction, the reduction of SNA increased from 36.9% to 42.8% with HONO heterogeneous chemistry. The reduction of 8h-O₃ caused by NO_x reduction remained at 1-4ppb without apparent change before and after adding HONO reactions in summer. No significant changes were seen in the O₃ reduction after the addition of HONO heterogeneous chemistry. The results in this study highlight the high effectiveness of NO_x controls for reducing SNA after considering the heterogeneous HONO formation in the ambient chemical complexion.
 

HONO PM2.5;O3