The air quality throughout most of Alberta has worsened and could remain high for some regions through mid-week, according to Environment Canada.
All of southern and central Alberta, as well as northern parts of the province, have been issued a special air quality statement Sunday morning, as wildfire smoke continues to cause poor air quality and reduce visibility.
The air quality health index is expected to reach 10 or higher in most affected regions Sunday and Monday, including Edmonton and Calgary, according to the weather agency.
Air quality can vary hourly and over short distances. Health index values are expected to moderate Monday due to southeasterly winds pushing the smoke, the statement says.
Health index values in northern and central parts of the province, however, are expected to remain high through mid-week, the statement says.
A health index rating of at least 7 is considered high-risk; 10 or higher is deemed very high risk.
People may experience increased coughing, throat irritation, headaches or shortness of breath, Environment Canada warns. Children, seniors, and those with cardiovascular or lung disease are especially at risk.
People with lung diseases, such as asthma and COPD, generally experience more serious health effects at lower levels of pollution, as it can aggravate their diseases. That may lead to increased medication use, doctor and emergency room visits, and hospital visits, the weather agency says.