The air pollution levels at Stockholm Arlanda Airport are equivalent to those found in a medium-sized Swedish town. Since 1994, air pollution at the airport has been measured regularly. The results show, among other things, that:
- Measurements of the quantity of sulphur and nitrogen (which contribute to acidification) in precipitation indicate no larger quantities per unit of area at Stockholm Arlanda than the average in Stockholm County.
- Studies of forests indicate that pine and spruce trees around the airport are losing needles on about the same scale as the average for trees in Stockholm County.
- Pollution levels are highest at the terminals and the most heavily trafficked roads.
How these atmospheric pollutants spread depends on several factors, including wind direction, wind speed and temperature. It is thus difficult to say what proportion of emissions affect different areas.