Ian Watkinson who chairs the National Education Union's health and safety group, was responding to the announcement by the education secretary earlier this week that the “bubbles” system for isolating pupils who are close contacts of positive Covid cases in school is likely to end on 19th July.
The requirement has seen an increasing number of children being kept at home for a 10-day period as infections in the community have risen.
The Local Democracy Reporting Service has obtained figures that reveal pupil self-isolations in Lancashire have increased by 32 percent in the space of a week.
A total of 12,256 children were told to self-isolate in the county council area - which excludes Blackpool and Blackburn with Darwen - in the seven days to 4th July. That is just over 3,000 more students compared to a week earlier - and represents almost seven percent of the school population.
Burnley had the highest number of youngsters self isolating, followed by Preston and Chorley - the same situation as the week before.
Mr. Watkinson said that “meaningful” measures to improve ventilation were required if bubbles are to be scrapped.
“In New York City, the authorities have put portable HEPA [High Efficiency Particulate Air] filtration systems in their classrooms. Of course, it doesn't stop the virus coming in, but it’s going to help stop it transmitting - so it seems like an absolute no brainer.
“They are about £400 a piece - and if you put one or two in a classroom, they'd make a massive difference. It would maximise ventilation [as opposed to] just opening a window - and there is time to invest it in now over the summer.
“At the moment, [the government is] just abandoning isolation - and that’s going to mean more transmission.
“Disruption to education is not being caused by isolation, but transmission and how high the case numbers are,” said Mr. Wilkinson, who represents Lancashire on the NEU's executive committee.
In the Lancashire County Council patch last week, there were 783 confirmed Covid infections amongst pupils - 6.3 percent of the overall number of isolations.
Staff isolations stood at 901 - up by more than 200 compared to the week before - with 104 confirmed Covid cases amongst their number.
A total of 224 schools are now affected by self-isolations across the county.
Meanwhile, Mr. Watkinson also called for the government to publish, as soon as possible, evidence from its trial of daily lateral flow tests for contacts of Covid cases in schools as an alternative to self-isolation.
The Department for Health was approached for comment.
In his statement in the Commons on Tuesday, Gavin Williamson said: "Keeping children in consistent groups was essential to control the spread of the virus when our population was less vaccinated.
"We recognise that the system of bubbles and isolation is causing disruption to many children's education.
"That is why we'll be ending bubbles and transferring contact tracing to the NHS Test and Trace system for early years settings, schools and colleges."
PUPIL ISOLATIONS IN LANCASHIRE
Number of pupils advised to self isolate in each district between 28th June and 4th July:
Burnley - 1,689
Chorley - 1,509
Fylde - 400
Hyndburn - 725
Lancaster - 1,470
Pendle - 609
Preston - 1,651
Ribble Valley - 524
Rossendale - 932
South Ribble - 910
West Lancashire - 836
Wyre - 1,001
LANCASHIRE COUNTY COUNCIL TOTAL: 12,256