Air fresheners and wood burners contribute to air pollution despite many people believing the reverse to be true, Sir Chris Whitty has said.

The Chief Medical Officer for England told MPs he would have “no problem” telling someone with an asthmatic child not to use air freshener.

He also said people who use wood burners should only do so “when it really matters to them for aesthetic reasons” rather than as the main way of heating their home.

Sir Chris said the risks from indoor air pollution are sometimes underappreciated because substantial progress has been made improving outdoor air quality in recent decades.

Wood burners should not be used a primary source of heat unless strictly necessary, Sir Chris Witty says (Alamy/PA)

The Commons Environmental Audit Committee was told products that can raise the risk inside include air freshener as well as candles and joss sticks.

Prof Whitty said he would be reluctant to advise Government to issue advice warning about the impact of air freshener because the data is not “strong enough”.

However, he added: “I would have no problem saying to people, ‘if you have got an asthmatic child, I recommend you don’t use an air freshener.’

“For Parliament to say something, I think, that’s rather different.

“I think one has to be very, very careful not to go ahead of where the evidence is but … I wouldn’t say to everyone, ‘don’t use air fresheners’ but I would say, ‘if your child has been in ICU three times this year, do everything you can to minimise the risk, here are some sensible things’.

“Actually, in the report we have laid out a section to allow doctors, nurses, others who are recommending, to say, ‘here are some common sense things: candles, joss sticks, a variety of things which, actually, if you’ve got a very high-risk person… (removing) these could help to reduce your risk.”

Earlier, he told the committee about 17% of particulate matter, which contains microplastics, in the air comes from wood burning.

This has increased by about 35% in the past decade but wood burners approved by the Department for Environment Food and Rural Affairs (Defra) using dry wood cause eight times less air pollution.

Sir Chris told the committee: “It is important that we very strongly encourage people who wish to use a wood burner, where that’s already allowed, to use one of the new designs with dry wood because they are much less polluting than designs we had 15 or 20 years ago.”

When asked by Clive Lewis MP whether he would install a Defra-approved wood burner in his home, Sir Chris said: “In a situation where people don’t have access to the gas network, are a long way from oil supplies, absolutely.

“There are a lot of people in rural areas who are reliant on wood burning as a form of heating, entirely appropriately, just as straight heating, but I would encourage them to move to a Defra-approved one and to use dry wood.

“There are also people who put them in for aesthetic reasons, reasonable enough, but what I would encourage them to do is to use them when it really matters to them for aesthetic reasons and not as the principal means of heating where that’s not relevant to them, where they could easily use a much less polluting one.

“So, essentially, it’s allowing people the choice for the thing they want but not getting around the fact that this is a relatively polluting way of heating a house.”