Smoke from the wildfires engulfing the U.S. West and Canada is carrying harmful air pollution as it reaches East Coast cities including New York and Washington, D.C., this week.

Driving the news: The coast to coast smoke clearly visible from space is due to the nearly 300 wildfires burning in British Columbia and the more than 80 large blazes in the US.

• The towering pyrocumulus clouds coming off these fires is lofting smoke all the way into the stratosphere, and the jet stream is carrying the smoke eastward across the country.

Our thought bubble: Due to the presence of small particulate matter, wildfire smoke can be hazardous to human health, even many, many miles downwind. The fires are also a source of carbon dioxide emissions, thereby acting to worsen global warming.

By the numbers: Smoke from the fires blanketed New York City sending its air quality index to an 170 before dropping to a still-unhealthy 158 on Tuesday — second only to the AQI of 174 in Krasnoyarks, Russia.

• Boston, Massachusetts, and Hartford, Connecticut, also recorded unhealthy AQI readings that were higher than 150.

Context: The wildfires, many of which started when a severe heat wave erupted in June, have been linked by scientists to human-caused climate change.

Scale of ongoing N America #wildfires with high daily total intensity & estimated emissions since 1 June for different states/provinces reflected in #CopernicusAtmosphere GFAS data as smoke covers coast to coast in 12-h AOD forecast from 20 July 00 UTC https://t.co/jaJ1cEEDyZpic.twitter.com/vtqVRlyL7L

— Mark Parrington (@m_parrington) July 20, 2021