Impacts of black carbon aerosol on photolysis and ozone

Compared with measurements of the fine particle matter in the Houston area, the simulated daily mean black carbon aerosol concentration is in agreement with observations in the urban sites.

Black carbon aerosol reduces the photolysis frequencies of J[O-3(D-1)] and J[NO2] in the planetary boundary layer by 10 - 30% when air pollution is highest in the Houston area. As a result, the ground level ozone concentration in the Houston area decreases by 5 - 20%. Our study demonstrates that the impacts of black carbon aerosol on photochemistry are important in polluted urban atmospheres.