The party is calling for an update in the Scottish Parliament and for the Scottish Government to set out what action will be taken in classrooms that fail assessments.
Nicola Sturgeon announced £10 million for councils to provide carbon dioxide monitoring for all schools and daycare services in a coronavirus statement in early August, as she said guidance for schools on ventilation was being strengthened.
The First Minister said the devices should be used to monitor air quality, with assessments completed and necessary improvements identified by the October holidays.
She said: "Ventilation is one of the most important ways in which the risk of Covid transmission can be reduced - and so improving it will be vital, now and in the future, to ensure that schools and childcare centres are as safe as possible."
Scottish Labour claims not enough has been done and highlighted that ozone disinfecting machines have been bought for every school in Wales.
The Welsh Government announced at the end of August it would provide £3.31 million for more than 1,800 machines to provide at least one for every school, college and university in Wales.
Scottish Labour education spokesman Michael Marra said: "The SNP Government has had all summer to act to improve ventilation, but far too little has been done.
"With cases in schools very high and winter on the way, there is simply no time to waste.
"Winter is looming, with temperatures set to plummet. That the SNP's ventilation strategy currently amounts to keeping the windows open is both farcical and dangerous.
"We simply cannot have children huddled together in freezing classrooms this winter.
"Make no mistake - failure to act now will put our pupils, teachers and their families in danger."
Education Secretary Shirley-Anne Somerville said: "We are providing local authorities with an additional £10 million to ensure that schools and childcare settings have access to CO2 monitoring. This is on top of £90 million Covid logistics funding already provided to councils.
"Many local authorities have already reported good progress in addressing ventilation issues in the school estate using our guidance, much of which has been in place since last year.”