The committee's report - into high concentrations of nitrogen dioxide, increasingly blamed for exacerbating the asthma which affects one in every seven British children - was slipped out by the Department of Health last week with unusual coyness, even by Whitehall standards.
No copies were sent to the press and requests for them were refused. And none of four leading experts on asthma contacted by the Independent on Sunday were aware of its publication.
The report Oxides of Nitrogen by the Advisory Group on the Medical Aspects of Air Pollution Episodes, says that only a 'few', 'occasional' and 'sensitive' people will suffer even from the highest levels of the pollution ever found in Britain. One leading authority accused it of 'brushing the problem under the carpet'.
It has already alarmed officials at the Department of the Environment who tried, without success, to modify its conclusions before publication. But the Department of Health says that its Chief Medical Officer, Dr Kenneth Calman, will circulate the document to all Britain's doctors in the New Year; the report says this is 'particularly important' to allay the fears of asthmatics.
Nitrogen dioxide, mainly produced in exhaust fumes, was described as 'of primary concern' and as 'perhaps the pollutant of greatest concern' by an Environment Department report earlier this year. Over the past 20 years levels of the pollutant have more than doubled in Britain, while they have been reduced in the United States.
In October, the Independent on Sunday revealed that levels of nitrogen dioxide in British cities were twice as high as the Government admitted - because it sited its monitoring stations away from heavy traffic, in defiance of EC law.
Last week's report recommends that no warning should be given to the British public about high levels of the pollution unless they exceed 600 parts per billion, nearly three times the safety limit set by the World Health Organisation 'for protecting public health from adverse effects of air pollution'.
In practice, if this proposal is accepted, no warnings will be given because the pollution never reaches this level in Britain. The record so far, reached in December 1991, was 423 parts per billion.
The report astounded authorities in the field. Dr John Whitelegg, of Lancaster University, who by coincidence published a widely publicised report on the same day showing a connection between pollution and ill-health.
He said: 'I cannot understand why the committee should come up with such conclusions. There is more than enough evidence to suggest that air pollution is a problem; we do not need people trying to brush it under the carpet.'