"Air pollution has decreased significantly since the 1990s. Since the beginning of this decade, there is no clear signal of a similar trend in pollution by particles, nitrogen dioxide and ozone in Germany, despite a continuous decline in emissions. Air quality varies to a more or less great degree from one year to the next. Average immissions levels in Germany show a steady drop in particulate matter (PM10) and nitrogen dioxide (NO2) away from congested urban areas towards the countryside." (Quoted from article)