Shoppers in Perth are being invited to take a "breathalyser test" as part of World Asthma Day.
A team of researchers from the University of Dundee will be in the St John's Centre on 1 May to offer the 90-second tests.
Nurses and research staff will also be on hand to distribute information on asthma and rhinitis, a group of conditions which includes hayfever.
Professor Brian Lipworth said the simple test could change lives.
He said: "This is a very simple test from which we can gain an initial impression of whether someone may be suffering from asthma.
"Many people experience asthma-type symptoms without ever seeking a diagnosis and we know that there are many people suffering from asthma who simply don't realise it.
"During a similar event in Dundee last year, we found many people presenting asthma symptoms or similar conditions that they had never had diagnosed before.
"The difference it can make to someone's life from having a condition like this diagnosed and properly treated can be really significant."
The Asthma and Allergy Research Group has a base within Perth Royal Infirmary which is carrying out a number of projects including dedicated research in asthma, allergic rhinitis and chronic obstructive pulmonary disease (COPD).