An analysis of 30 years of surface ozone concentrations in Austria: temporal evolution, changes in precursor emissions and chemical regimes, temperature dependence, and lessons for the future.

Despite substantial reductions in anthropogenic emissions of nitrogen oxides (NO ) and non-methane volatile organic compounds (NMVOCs) in Austria over the 30 year time period 1990-2019, summertime surface ozone (O) concentrations still exceed frequently and over wide areas the ozone maximum 8 hour mean target value for the protection of human health. We present a detailed analysis of observations of O and NO to (1) disentangle the main processes propelling O formation such as precursor emissions and meteorology and (2) quantify the impact of NO reductions and (3) estimate the effect of climate warming. The temperature sensitivity of surface O production is assessed separately for NO and VOC limited regimes.