BEIJING, China -- Smog is the big story in Beijing. It’s dominating international news coverage.

Photo by KGW's Stephanie Stricklen

Tiananmen Square during the Olympics.

KGW’s Stephanie Stricklen caught up with an environmental chemist from Oregon who is in Beijing to collect air samples.

Oregon State University Professor Staci Simonich says Beijing is a perfect place to collect samples because the air quality is so poor.

"It all started at the top of Mount Bachelor,” says Simonich.

When a testing site on the mountain turned up unexpected contaminants, her team turned detective and eventually traced the problem to air masses from Asia.

"We're back for the Olympics. And the way it works is large volumes of air are drawn through a series of filters."

Three filters trap progressively smaller particles. The first snags sand and soil.

"The second two trap the finer particulates that are from combustion sources, maybe from factories, maybe from automobiles and also from reactions in the atmosphere."

This year, the samples are dark.

"It's among the darkest I've ever seen in my years of air sampling."

In a lab, she weighs and labels each filter. She won’t know exactly what got trapped until she gets home.

"I'll put them in a freezer and keep them until we return them back to Oregon State."

It’s a collaboration in science and human health that spans two cultures.