Friends of the Earth Scotland has published league tables which they claimed identify Scotland's most polluted streets.
Hope Street in central Glasgow is named as the area with the most serious nitrogen dioxide (NO2) pollution problem in the country. High levels of NO2 are linked to asthma and other respiratory problems.
Market Street in Aberdeen is claimed to be the worst in Scotland for particulate matter pollution (PM10). Health experts say long-term exposure to air pollution caused by particulates is linked to a higher risk of heart attack.
Dr Richard Dixon, director of FOE Scotland, said the research showed that air pollution was also a threat to health in smaller towns and villages. "We have air pollution problems in all of our big urban areas. Action is long overdue. We still haven't met health protection targets which we were supposed to meet in 2005 and 2010. But there are some surprising places in the results as well. For example, we're missing health targets in Crieff, in Perth, and even in small villages in some parts of West Lothian and North Lanarkshire. It's taken us a decade to talk about it, but do very little, and we need to see much more action if we're going to solve the problem and give ourselves the clean air we deserve."