The air in Amsterdam is so polluted that residents suffer the same health detriments by breathing it that they would do from passively smoking 6.4 cigarettes, according to calculations by environmental organization Milieudefensie, Het Parool reports.

Milieudefensie, the Dutch Friends of the Earth, used data on air quality in 393 Dutch municipalities and a scientific calculation model to figure out what the health effects of breathing unhealthy air are compared with passive smoking. The calculation model used was developed by scientists from GGD Amsterdam, RIVM and the Utrecht University.

Rotterdam was found to be the most unhealthy city when it comes to air quality - breathing the Rotterdam air is equal to passively smoking almost 7 cigarettes a day. Rijswijk and Schiedam took second and third place. Amsterdam came in fourth with 6.4 cigarettes. Vlieland has the cleanest air, with 2.8 passively smoked cigarettes a day.

Second-hand smoke from cigarettes is becoming less and less common due to a smoking ban in most public places. But according to the environmental organization, your health doesn't care whether you're breathing second-hand smoke or polluted air. Lung cancer and heart disease, among other things, occur in both cases.

"Passive smoking is now more caused by cars, intensive farming and coal-fired plants than cigarettes", Bram van Liere of Milieudefensie said, according to the newspaper.

Earlier this month the environmental organization filed a lawsuit against the Dutch State demanding that the air quality in the country be improved.