Air pollution in the St. Albert area prompted a warning from Environment Canada late Saturday night due to atmospheric conditions.
Environment Canada said pollution levels were rising around the city because of stagnant winter weather conditions.
"Air quality is expected to remain poor until Monday afternoon, when winds are forecast to increase," the organization stated.
St. Albert, Edmonton and Sherwood Park were all put under the air quality alert at 11:35 p.m.
Fort Saskatchewan, Vegreville, Redwater and Smoky Lake also came under the warning.