Ozone is a key player of atmospheric chemistry, an important air pollutant, and hence a major target of air quality modeling and management.
An observation-based chemical zero-dimensional box model was used to estimate the in-situ ozone production and examine the sensitivity to precursors and to different meteorological conditions in Innsbruck.
Three different case studies for Innsbruck were addressed: the weekend effect, the influence of föhn and a temperature change scenario.
In addition, and for comparison four other urban environment were evaluated, and for the city of Sao Paulo a sensitivity assessment to precursors was performed.
It could be shown that Innsbruck undergoes a NMVOC-limited ozone regime, resulting in a 154 % increase in photochemical ozone production during weekends. It was demonstrated that a considerable reduction in nitrogen oxides increases net ozone production during weekends.
In addition it was found that a possible reduction of NMVOC induces lower ozone formation rates on weekdays than on weekends.
Atmospheric chemistry conditions of Innsbruck are also compared to several urban megacities which all fall under $NMVOC$-limited ozone regime; these megacities tend to show high fraction of anthropogenic NMVOC concentration than the biogenic VOC. For Sao Paulo city and Beijing although, biogenic NMVOC contribute with respectively 22.5% and 24.9% to the total NMVOC-reactivity.
A qualitative analysis of ozone concentrations in conjunction with the Leighton ratio observed during föhn events suggests that this meteorological event is coupled with long-range transport of ozone over the Alps. It could be shown that föhn episodes are characterized by higher levels of ozone production compared to sunny day. This feature is likely to be attributed to an air mass exchange and the new air mixture favors photochemical ozone production.
Model predictions for temperature increase scenarios revealed that peak ozone production will increase by 74% on an average if sunny-day temperatures will rise from 20°C to 30°C.