Asthma sufferers are being asked to volunteer for a study which aims to measure how better ventilation could improve their condition.
Many asthma sufferers are allergic to house dust mites
The work will tackle dust mites, which thrive in homes with central heating and fitted carpets - and are often responsible for triggering asthma.
Doctors from Glasgow University want to improve ventilation in 150 homes in Lanarkshire to measure the effect.
Volunteers aged between 16 and 60 are being encouraged to take part.
Doctors from the university will conduct research at Monklands General Hospital.
Volunteers will not change any inhaler medication but instead a team of architects from the University of Strathclyde will improve ventilation in the homes.
Many patients with asthma are allergic to house dust mites and improving ventilation has been shown to reduce their prevalence.
Dr Gillian Vallance, clinical research fellow, said: "Asthma is the most common chronic disease in Scotland and house dust mite is a common trigger.
"The introduction of central heating and fitted carpets over the last 20 years has provided the perfect climate for the house dust mite to thrive.
"We hope that this study will provide an effective way to reduce dust mites and improve asthma."
Dr Stirling Howieson, of the department of architecture at the University of Strathclyde, said poor indoor air quality in homes was the main reason Scotland had the highest prevalence of asthma.
"Mechanical heat recovery ventilation systems can provide pre-warmed fresh air and reduce indoor pollution and humidity, inhibiting dust mite activity," he said.
Volunteers will have their carpets steam-cleaned and a ventilation unit will be fitted in the loft.
Half of the units will be switched on at the beginning of the study, with the other half activated in 12 months time.
The condition of those in the two groups taking part will be compared over that year.
Those taking part will have allergy and breathing tests to see if they are suitable and will then be reviewed at clinic every three months to see if their asthma is improving.