The course of asthma varies from one child to the next. Symptoms may begin at any age, may persist or stop, and then may recur many years later.
Given asthma is about five times more common in Western societies, this suggests lifestyle plays a major role.
Children, older people and those with respiratory illnesses such as asthma and COPD are particularly at risk of smoke-related health problems.
Due to summer wildfires, children living on the West Coast have been breathing some of the most polluted air on record.