Bus lane fines could soon be used to pay for cameras to police a ban on gas-guzzlers.
Transport Minister Humza Yousaf wants Aberdeen to be one of the first cities in Scotland to install automatic number plate recognition (ANPR) technology.
It would be used to enforce a “low emission zone” which less-green cars and lorries would have to pay to use.
But the Conservatives played down the prospects of the city pioneering the approach.
Councillors will vote today on whether to spend £50,000 of the £1million-plus raked in a year in bus lane fines on around 25 ANPR cameras.
They would “provide high accuracy journey time information, with the potential to collect data on vehicle types and emissions”.
Mr Yousaf said he had held “very constructive discussions” with Scotland’s biggest urban local authorities over the environmental measure.
Before last month’s election, Labour hoped Aberdeen would be the first in Scotland to operate one of the zones.
It championed a £10million scheme that would have restricted access to streets with the poorest air quality.
Wellington Road was this year named as the third-most-polluted street in Scotland with Union Street also in the top 10.
The proposal was warmly welcomed by environmentalists but motoring groups warned it could “kill off” the city centre.
And it was last night met with only very lukewarm support from the Conservatives, who since the election outnumber Labour in the townhouse coalition.
The party’s transport spokesman, MSP Liam Kerr, said they would want to see it in operation in other cities before making a decision.
“In principle, I would welcome any effort to improve air quality in our biggest cities,” he said.
“However, we need to ensure this does not simply become another tax on the motorist – particularly those who drive older vehicles and may be unfairly penalised.
“Bus lane enforcement has become something of a revenue raiser for the council, with little evidence it has led to the desired change in behaviour.
“The Scottish Conservatives will be closely monitoring the progress of low emission zone pilot schemes in Scotland.”
Aberdeen Labour transport spokesman Ross Grant said the authority was “absolutely committed to ensuring that air pollution is proactively tackled”.
Councillors would have a chance in June to examine a feasibility study into the how LEZs could be implemented and enforced, he added.