US Under Smokescreen: How Canadian Wildfires Affecting Millions and Air Quality Across the Country

A large area of ​​the United States -from Michigan and Ohio to New York and Washington DC- continued on Thursday under a mass of smoke coming from Canada and under alerts in which more than 40 million people have been asked to limit or avoid completely outdoor activities.

Why has this mass of smoke reached the US due to the fires in Canada: The smoke has been carried by a current of winds that comes from the north and that has come across a low pressure zone in the northeast of the United States. That combination helped build up the smoke, and because weather conditions haven’t changed significantly, that smoke has intensified, he explains. The Weather Channel.

How much longer will the smoke last: The wind current mentioned above moves counterclockwise and this would allow the strong concentration to dissipate in some places during part of this Thursday afternoon. However, the smoke will become dense again late tonight, according to forecasts by the National Weather Service (NWS).

• This map prepared by the NWS helps to understand it.

• The weather pattern would change towards the weekend: the low pressure system that has been static in the Northeast United States would move eastward and leave the country, and that would help the winds not remain ‘stuck’ then and the smoke coming from the north.

• “That should help dissipate remnant smoke over the (affected) region and prevent new smoke from moving directly from Canada into the eastern United States,” according to The Weather Channel.

Which are the areas with the worst air quality: As of noon Thursday, the real-time map from AirNow (a partnership between EPA, NOAA, NASA and other agencies) showed a vast area of ​​the country, from Michigan and Ohio to Massachusetts and Washington DC, with red dots. , purple and maroon, the three strongest categories on the scale of six of its air quality index.

• This index ranges from 0 to 500 and until our last review there were dozens of areas above 200. To understand the severity, every time the air quality exceeds 100 it becomes unhealthy for some sensitive groups, according to this index. If it exceeds 300 it is already considered dangerous.

• Harrisburg, Pennsylvania, for example, showed a score of 380 this afternoon, asking residents to stay indoors. In this page you can check how the area where you live is.

Must take into account: Fire season in Canada is just beginning. In that country, hundreds of forest fires burned this Thursday, which have burned 3.8 million hectares, according to a report by the Reuters agency.

And why did the smoke turn some places orange?: Media They explain that it is due to sunlight, what happens to its different waves when they pass through the Earth’s atmosphere, and the amount of particles in the air.

• Light from the Sun, NASA explains, travels in short (blue) and long (red) waves that scatter in all directions when they reach our atmosphere and meet gases and particles in the air. We usually see blue skies because short blue waves are the most easily scattered in the atmosphere. When there is pollution, as in this case smoke, these short blue waves are dispersed much more and allow the passage of the colors of other waves, such as red through the atmosphere, adds NASA.