The city will be the only one which will fail to meet to the Scottish Government's demands to address pollution problems by the end of 2015.
Environment Minister Paul Wheelhouse told MSPs that a "missing link" in the M8 would delay improvements to air quality until 2017 or 2018.
But campaigners have hit back, questioning the logic behind expanding a road and improving air quality, claiming it will just encourage more traffic.
Glasgow Green MSP Patrick Harvie said the delay was "utterly unacceptable".
The news comes after the latest air pollution figures revealed three Glasgow streets were among the worst polluted in the country.
Hope Street, Dumbarton Road and Byres Road are contaminated by toxic concentrations of traffic fumes, according to the latest official air pollution monitoring results for 2013.
One type of particulate pollution on its own is believed to be responsible for 1600 deaths a year in Scotland.
Last year, levels in Glasgow's streets averaged well above government guidelines.
As reported in the Evening Times, work is due to start to upgrade the A8 between Baillieston and Newhouse to motorway status.
The details for the improvements claim it will reduce emissions and tackle climate change by improving air quality and providing health improvement.
A Scottish Government spokeswoman said the improvements are predicted to result in "substantial beneficial impacts" for properties close to the existing A8.
But, the 2007 environmental report for the M8 Baillieston to Newhouse claims the overall local air quality impacts are likely to be slightly worse.
This is referring to those living nearest to the site, with 3602 of those living up to 25m away likely to experience deteriorated air quality, while only 2460 would experience improved air quality.
Mr Harvie said: "This revelation that Glasgow must wait three years longer than other cities for decent air quality is utterly unacceptable.
"The Minister's argument that upgrading parts of the M8 will make the difference is just fanciful.
"Anyone travelling in the heart of the city will know that we need fewer cars, cleaner buses and safer routes for cycling."
Emilia Hanna, a campaigner at Friends of the Earth, said widening the M8 through the 'Missing Link' project will not fix Glasgow's air pollution problem.
She said: "Air quality is expected to be worsened for thousands of people living along the stretch between Baillieston to Newhouse.
"And for those living in the centre of Glasgow, the new lane will simply encourage more traffic to pour into the city, bringing with it more toxic air pollution."
Mr Wheelhouse said the government was playing a "strong partnership role" on transport emissions and was working with local partners to address "pinch points."
He said: "Glasgow is the one location where we suspect that there will still be a problem beyond 2015 because of the missing link on the M8.
"However, we have programmed expenditure to address that and it should be dealt with by about 2017-18 on current projections."
A Scottish Government spokesman said: "Construction of the new M8 between Baillieston and Newhouse and improvements to the M73 and M74 are predicted to result in substantial beneficial impacts for properties close to the existing A8."