Environment Canada issued a special air quality statement on Thursday, July 31 because of smoke from wildfires on the prairies moving through areas including Windsor-Essex, Chatham-Kent, and Sarnia-Lambton.
The air quality in the region improved later in the day and was lifted just after 2 a.m. on Friday.
Wildfire smoke exposure can cause symptoms such as eye, nose and throat irritation, headaches or a mild cough. More serious symptoms are wheezing, chest pain or severe cough.
Environment Canada recommends limiting your time outside.