EVERY morning and every evening, Richard Haggerty takes a puff from a blue and a puff from a lilac inhaler.

During the day he draws on the blue device whenever he runs out of breath.

''He's very chesty,'' said his mother Linda MacKenzie. ''He cannot run about the same as other boys. He gets tired very quickly and he gets frustrated because he cannot do things.''

This is the impact asthma - a condition that affects 35% of young teenagers in Scotland - has on the seven-year-old's life, and Ms MacKenzie believes it is the Ibrox flat in which she lives that has caused the illness.

It is clean and cosy inside their tower block home, the toys are stacked out of the way in a hallway cupboard, the beds are neatly made. It does not immediately look like a dwelling that could make someone unwell. But there is a rash of black marks spreading along the bottom of the living room walls and behind Richard's bed. Photographs show fungi clustered on the kitchen ceiling.

Ms MacKenzie, who has lived in the area all her life and is otherwise content with her address, said: ''I am convinced the environment in here has prompted it. We used to have different windows and we got in these new windows and it was shortly after that you could see the dampness appearing and shortly after that he started appearing not well. The other windows were more draughty. These ones are double-glazed and there is just less air getting in and out.''

Her observation that Richard's bout of chest infections followed this improvement in insulation echoes a theory studied by academics.

Allergies and diseases such as asthma have exploded in the past 40 years to the extent that one in three people will experience a reaction at some stage of their life and one in four are suffering at any point in time.

What has triggered this mass intolerance of relatively inoffensive items such as pollen, peanuts and dust is not known, although the reasons are likely to be multiple.

Dr Stirling Howieson, of the department of architecture and building science at Strathclyde University, is convinced the desire for airtight, energy-efficient homes must take some of the blame. He said: ''Every single piece of evidence supports that the change of living conditions is responsible for the increase of asthma.

''You can trace the asthma pandemic from the Opec oil crisis in the 1970s. The clean air acts sealed the flues up and then we sealed everything up and there was a massive increase in double-glazing which happened around that time.''

His department's research has shown eight out of 10 living-rooms and bedrooms had higher levels of a dust mite protein linked to asthma than the thresholds the World Health Organisation considers sufficient to sensitise people predisposed to allergies.

Dr Howieson said the WHO exposure thresholds for sensitisation to dust mites were two micrograms (mcg) of a protein found in their faecal pellets per gram of house dust.

A sample taken from the bedroom carpet in Richard's home had 695mcg of the protein per 1g of house dust and a sample from his mattress surface 1400mcg of the protein per 1g of house dust.

In his report on his survey on the home, Dr Howieson said: ''The concentrations of Der p1 (the dust mite protein) found in this dwelling are the highest I have comes across in six years of research into this area. Exposure to this level of house dust mite protein is highly likely to cause sensitisation and precipitate asthmatic symptoms, particularly in children with immature immune systems.''

He added: ''The tenant can show she bought all this stuff (soft furnishings) not long ago so the dust mites have colonised and bred at an astonishing rate. The tenant is pretty fastidious. House dust mites do not like mankiness; they like the same environment we like, clean, warm and slightly humid. It is not that the parent is doing anything wrong; it is the conditions.''

facts and effects

About 300 million sufferers worldwide, with numbers expected to grow by a third in next 20 years. Scotland has highest incidence, with 18.4% of the population diagnosed.

UK numbers rose three to four-fold in adults and six-fold in children in past 25 years.

Attacks are of breathlessness and wheezing, varying in severity and frequency.

During an attack tiny air passages in the lungs swell, narrowing the airways and restricting the flow of air.

World Health Organisation says strongest risk factors for developing asthma are exposure, especially in infancy, to indoor allergens such as house dust mites in bedding, carpets, and furniture, cats and cockroaches, and a family history of asthma or allergy.