Ozone smog was first discovered in the Los Angeles basin in the 1940s, an area where traffic emissions of nitrogen oxides (NO and NO2) efficiently promote photochemical air pollution. The nitrogen oxides, released from the combustion of fossil fuels and also by biomass burning, act as catalysts of ozone formation. In turn, this reduces air quality and impairs human health, agricultural crops and natural ecosystems. Furthermore, ozone is a greenhouse gas, so that its increasing concentration in the troposphere contributes to climate change. In the post-war industrialization in the 1960s and 1970s, ozone increased rapidly in Europe and the USA. In addition to Los Angeles, especially the eastern USA and southern Europe suffer from high ozone concentrations in summer, so that air quality standards are often violated. Nevertheless, the ozone increases have been moderated after 1980 by the introduction of catalytic converters in car exhausts and the mitigation of industrial air pollution.
The article in Science is based on ozone measurements by the Max Planck Institute for Chemistry (Mainz) and the German Weather Service (Hohenpeienberg and former Meteorological Observatory Hamburg), taken on ships sailing the Atlantic Ocean since 1977. The results confirm that in middle latitudes in the northern hemisphere the o
Contact: Prof. Jos Lelieveld