Morning Extra - The Investigation - Childhood Asthma

Are modern homes causing childhood asthma? Ken MacDonald investigates claims that Scotland's childhood asthma pandemic has been due to the infestation of Scottish homes with house dust mites. Researchers at Strathclyde University say modern construction methods are creating ideal conditions for dust mites to thrive, but other scientists aren't so sure and campaigners are taking to the courts instead. This morning's investigation looks at theories including damp homes, lack of fresh air and kids spending too much time indoors. Has your family had problems with asthma, and what do you put it down to? Plus, we hear about a campaign by the Unite union urging restaurants and hotels to sign a "fair tips charter". Graham Stewart takes your calls, texts and emails.