Air pollution is contributing to about 40,000 early deaths a year in the UK, the Royal Colleges of Physicians and Paediatrics and Child Health have said.

While the pollutants have changed over time – from coal soot to diesel vehicle emissions – the health risks remain.

Tobacco still poses the biggest indoor threat, but wood-burning stoves, spray deodorants, cleaning products, air fresheners and fly spray contribute.

Mould and mildew in poorly ventilated rooms can also cause illness.

“Being indoors can offer some protection against outdoor air pollution, but it can also expose us to other air pollution sources,” the report says.

“There is now good awareness of the risks from badly maintained gas appliances, radioactive radon gas and second-hand tobacco smoke, but indoors we can also be exposed to NO2 [nitrogen dioxide] from gas cooking and solvents that slowly seep from plastics, paints and furnishings.

“The lemon-and-pine scents that we use to make our homes smell fresh can react chemically to generate air pollutants, and ozone-based air fresheners can also cause indoor air pollution.”

Co-author Prof Jonathan Grigg said there was now clear evidence air pollution – largely from factories and traffic – was linked to heart disease and lung problems, including asthma.

“As NHS costs continue to escalate due to poor public health – asthma alone costs the NHS an estimated £1bn a year – it is essential that policy makers consider the effects of long-term exposure on our children and the public purse,” he said.

Prof Grigg said the public could also help by:

  • walking, cycling or taking the bus or train instead of driving, when possible
  • keeping gas appliances and solid fuel burners in good repair
  • making homes more energy efficient

Prof Stephen Holgate, who chaired the reporting group, warned against complacency.

“We all have a part to play to cut environmental pollution,” he said.

“We can’t see it, smell it or taste it, which is why people do not necessarily think we have a problem.

“But we do have a serious problem still, even though emissions for some pollutants have gone down.

“It’s a big public health issue and, as doctors, we have a duty to speak out about it.”