Smoke from west coast wildfires has spread as far as eastern Canada, according to weather experts.
Clouds of smoke had pushed all the way to Atlantic Canada, creating poor air quality in several provinces, The Weather Network reported.
The Atlantic provinces are made up of New Brunswick, Nova Scotia, and Prince Edward Island, along the most easterly province of Newfoundland and Labrador.
Satellite images also showed that smoke from wildfires in the American West had reached as far as Europe, scientists said on Wednesday.
Data collected by the European Union's Copernicus Atmosphere Monitoring Service found smoke from the fires had traveled 8,000 km (almost 5,000 miles) through the atmosphere to Britain and other parts of northern Europe.
The European Centre for Medium-Range Weather Forecasts, which operates some of the Copernicus satellite monitoring systems, said the fires in California, Oregon and Washington state have emitted an estimated 30.3 million metric tonnes (33.4 million tons) of carbon.
"The scale and magnitude of these fires are at a level much higher than in any of the 18 years that our monitoring data covers, since 2003," Mark Parrington, a senior scientist and wildfire expert at Copernicus Atmosphere Monitoring Service, said.
Parrington said the smoke thickness from the fires, known as aerosol optical depth or AOD, was immense, according to satellite measurements.
"We have seen that AOD levels have reached very high values of seven or above, which has been confirmed by independent ground-based measurement," he said. "To put this into perspective, an AOD of one would already indicate a lot of aerosols in the atmosphere."