Scania (Skåne) is the southernmost county in Sweden (Fig. 1), covering an area of around 11,350 km2 (about 2% of the total area of Sweden). It is one of the most densely populated areas of the country, with about 1.1 million people (approximately 11% of the total Swedish population). The level of air pollutants in the wes- tern part of Scania (where most people live) is higher than in other areas of Sweden, due to road transport to and from the European continent and a considerable amount of cargo shipping and ferry transport along the coast. However, annual mean NOx on the west
coast of Scania in 1999 was around 20 mg/m3 (Sjöberg et al., 2006),
which is well below the present-day WHO air quality guideline value of 40 mg/m3 (WHO, 2006), and levels of ozone are around
50 mg/m3 well below (health) guideline value of 120 mg/m3