Numerical study on the ozone formation inside street canyons using a chemistry box model

Tropospheric ozone is a secondary air pollutant produced in the presence of nitrogen oxides (NO_x),volatile organic compounds (VOCs),and solar radiation.In an urban environment,ground-level vehicular exhaust is the major anthropogenic source of ozone precursors.In the cases of street canyons,pollutant dilution is weakened by the surrounding buildings that creates localized high concentration of NO_x and VOCs,and thus leads to high potential of ozone formation.By considering the major physical and chemical p...

Modeling heterogeneous chemical processes on aerosol surface

To explore the possible impact of heterogeneous chemical processes on atmospheric trace components, a coupled box model including gas-phase chemical processes, aerosol thermodynamic equilibrium processes, and heterogeneous chemical processes on the surface of dust, black carbon （BC） and sea salt is set up to simulate the effects of heterogeneous chemistry on the aerosol surface, and analyze the primary factors affecting the heterogeneous processes. Results indicate that heterogeneous chemical processes on the aerosol surface in the atmosphere will affect the concentrations of trace gases such as H2O2, HO2, O3, NO2, NO3, HNO3 and SO2, and aerosols such as SO42-, NO3- and NH4＋. Sensitivity tests suggest that the magnitude of the impact of heterogeneous processes strongly depends on aerosol concentration and the surface uptake coefficients used in the box model. However, the impact of temperature on heterogeneous chemical processes is considerably less. The ＂renoxification＂ of HNO3 will affect the components of the troPosPhere such as nitrogen oxide and ozone.