Asthma is found across all age groups and it often presents as a cough. Allergic rhinitis and reflux esophagitis often cause cough too. Bronchial provocation testing helps identify those people with a cough who have asthma from those with esophagitis. The prevalence of asthma is increasing and air pollution is probably part of the reason. Taking a careful history may identify what is new in the environment that could explain why it happened. Traffic pollution is an important factor.