Concerns have been raised about the poor quality of indoor air in Northamptonshire, particularly the effects on children who are on average spending just over an hour a day outside.
Respiratory problems among children may be exacerbated by indoor air pollution in homes, schools and nurseries, according to the study, published last month.
The report covers many different aspects of indoor air pollution, including radon, which Public Health England says is responsible for over 1,100 deaths in the UK every year.
Large parts of Northamptonshire lie in the highest risk band where it is estimated that more than 30 per cent of homes will contain radon concentrations in excess of the recommended limit.
Radon is invisible, has no smell or taste so homeowners and landlords in high-risk areas are encouraged to test their buildings and make adjustments to reduce levels.
Charles Edwards, director of radon testing and mitigation firm PropertECO, said: “We work nationwide, however the highest concentration we have dealt with was in Northampton.
"Certain parts of the property had radon levels more than 150 times higher than the maximum level advised by the World Health Organisation.
"We were able to successfully reduce the levels using a combination of specialist fans.”
The Royal College of Paediatrics and Child Health (RCPCH) and the Royal College of Physicians (RCP) study found children spend an average of just 68 minutes outside per day.
The scientists linked indoor air pollution to a range of childhood health problems including asthma, wheezing, conjunctivitis, dermatitis and eczema.
Sources of indoor air pollution include smoking, damp, the burning of fossil fuels and wood, dust, chemicals from building materials and furnishings, aerosol sprays and cleaning products.
The authors warn that indoor air quality tends to be poorer in low quality housing where ventilation may be inadequate or insufficient.
Professor Jonathan Grigg, from the RCPCH, said: "We’re finally paying attention to the quality of our outdoor air and this is long overdue.
"It’s harder to get population-level data on the quality of indoor air but the evidence in this report paints a worrying picture."
Testing for radon is simple and inexpensive, according to PropertECO, costing around £40 for an average home.
Mr Edwards said: “We are frequently contacted by concerned parents who have only just learned about radon, usually due to it being flagged up when buying a house.
"As radon is an invisible hazard, people are often completely oblivious to the risks it could be posing to their families.
"If radon glowed bright green and could be seen drifting through our homes, there would be far more action and fewer cases of lung cancer occurring each year.
"We are urging parents to test their homes and identify whether their property is affected.”
For more information about radon and what to do about it, visit the government website ukradon.org.