North America’s pollution may be coming from other continents

A new study has found that up to half the pollution that is impacting North America's air quality and accelerating climate change on our continent could be coming from overseas.

The research team, including scientists from the University of Maryland, NASA Goddard Space Flight Center and the Universities Space Research Association, examined satellite data and determined that airborne particles and pollutants can, and have been, carried to North American by winds from Europe, Africa and Asia.

However, pollution from industrial sources and power generation wasn't the main problem.

"People have been concerned about how an emerging Asian economy and increased man-made pollution will influence North American air quality and climate, but we found that dust makes large contributions here," said Hongbin Yu of the University of Maryland, according to Science Daily. "So we cannot just focus on pollution. We need to consider dust."

Storms in the Sahara and Gobi deserts can loft dust high into the atmosphere, where they are carried by the winds across the oceans. The researchers found that over 87% of the foreign particulates in our air are dust from Asia, with the remaining 13% evenly split between fossil-fuel burning in Asia and dust from Africa.

I observed this kind of event back in April of 2010, when the U.S. Southeast experienced high particulate matter concentrations that couldn't be explained solely by local sources. By looking a bit further afield, we discovered Saharan dust had been blowing across the Atlantic on the same winds that typically drive hurricanes towards the East Coast. That dust mixed with local industrial pollution and smoke from fires in the region to make the air quality in the area even worse.

This kind of discovery really drives home the point that the atmosphere is something shared by us all. What each nation does within its borders can still have big impacts on other countries, even on the other side of the world, and with the added threat of more frequent droughts on the horizon, the effects of dust transport can only get worse with time.