PEDESTRIANS, residents and motorists are enduring dangerous levels of air pollution because of a five-year delay to plans to cut emmissions
The Holyrood and Westminster governments are also at risk of multi-million-pound fines for breaching environmental law.
Campaigners have warned most of Scotland's cities will be 10 years late when they finally meet a European air quality standard.
Friends of the Earth Scotland said a legal limit on the amount of nitrogen dioxide should have been met in 2010 but most cities - including the capital Edinburgh - would not achieve this standard until 2020.
Glasgow has two of the most polluted streets in the country in Hope Street and Byres Road. It is not due to meet air pollution safety limits until 2025.
Edinburgh's Queensferry Road, Seagate in Dundee and Union Street in Aberdeen are also high on the list.
The UK Government has already been found guilty of breaking air pollution law, and Scotland faces similar action.
Friends of the Earth Scotland campaigner Emilia Hanna said: "These delays see the prospect of clean air slipping over the horizon for people living in Scottish towns and cities. The Scottish Government has thus far proved itself unwilling to take the steps necessary to tackle this public health crisis."
Toxic particles from vehicle exhausts are blamed for killing at least 1600 people a year in Scotland, and 166,000 a year across Western Europe. They can trigger heart attacks, aggravate lung diseases and cause infections.
The UK agreed to an air pollution law that required levels of nitrogen dioxide gas in cities to be brought below safety limits by 2010. But after it had difficulty meeting this target, it applied for extensions until 2015.
The European Commission launched legal action against the UK in February, after it accepted Glasgow and other cities would not meet the target until 2020.
The Department for Environment, Food and Rural Affairs (Defra) has now issued renewed projections that say Glasgow is not expected to comply with pollution standards until 2025.
Edinburgh, central and northeast Scotland had been expected to comply with the extended deadline but are not now expected to meet safety limits until 2020 .
This means the areas could become implicated in a second legal action being brought against the UK Government by the environmental lawyers organisation ClientEarth.
Alan Andrews, a lawyer with the organisation, said: "Our case now has even wider significance for air quality throughout the UK. Unless the Government comes up with a plan to tackle pollution from road traffic, people will suffer from illegal levels of pollution for decades to come."
Last year the UK Supreme Court declared the UK Government in breach of its legal duty to meet nitrogen dioxide safety limits. The court has asked the European Court of Justice to rule on what action it can compel the Government to take.
A Scottish Government spokesman said "These revised projections from Defra are very disappointing, as previous projections suggested that all parts of Scotland would comply with legal limits for nitrogen dioxide pollution from traffic within the next couple of years."