Smoke from dozens of intense wildfires burning in western Canada drifted into the United States, prompting officials in Colorado and Montana to issue air quality alerts.
The Colorado Department of Public Health and Environment issued watches and advisories for the eastern half of the state, including Denver, from Saturday afternoon through Sunday afternoon. He warned that air quality could be unhealthy during that period.
“People with heart or lung disease, the elderly and children should not do prolonged or vigorous activities; All others should minimize prolonged or heavy activities,” the department said.
According to the department, the air quality index touched 168 in some parts of the Front Range on Saturday due to particulate pollution. A reading between 151 and 200 represents unhealthy conditions that may affect sensitive groups as well as some members of the general public.
Air quality warnings also went into effect Saturday in Montana, with the highest concentrations of smoke in the central and eastern parts of the state, according to the Department of Environmental Quality.
The Utah Department of Environmental Quality noted Friday that it was beginning to detect smoke on its monitors in the northern and eastern parts of the state. He urged residents not to indulge in outdoor activities in areas with visible smoke or haze.
The smoke caused widespread haze in Idaho during the week, according to its Department of Environmental Quality.
In Canada, fires are burning primarily in the province of Alberta, where thousands of residents have been evacuated and regional authorities have issued a state of emergency alert. There is also a fire in British Columbia.
In Calgary and Edmonton, Alberta’s two largest cities, the Canadian government’s Air Quality and Health Index on Saturday determined the health impact as “very high risk.” Vulnerable groups such as children and the elderly were advised to avoid physical activity outside.