Response of surface ozone to atmospheric aerosol absorption is more sensitive than to scattering in a semi-arid region

Interactions between atmospheric aerosols and ozone have significant impact on air pollution and the climate. However, the relative importance of the response of surface ozone to aerosol scattering and absorption has not been well quantified from in situ observations. Results derived from a one-year in situ observational study conducted in a semi-arid region showed that the response of ozone to aerosol absorption was more sensitive than to scattering. Specifically, the change in surface ozone from low to high absorption coefficients was approximately five times that from low to high scattering coefficients. The mass scattering and absorption efficiencies, rather than the single-scattering albedo, which are commonly applied in numerical simulations, were able to clearly distinguish surface ozone. The positive correlation between aerosol and ozone in summer showed the promotion of secondary aerosols by ozone. This study provides robust observational evidence of the response of surface ozone to aerosol scattering and absorption.