Officials and residents of Southern California may be underestimating the health threats posed by wildfires in the area. A recent analysis of particulate matter from the 2007 wildfires in Southern California shows that the emissions from the fires produce a significantly larger aerosol than that typically seen in urban environments due to traffic sources.

“Tracers of biomass burning (eg potassium and levoglucosan) were elevated by two-fold during the fire period,’ says Sioutas. “Water-soluble organic carbon was also higher during the fire event. This makes these particles from wood smoke more bioavailable, thus more readily absorbable by our system than particulate matter from traffic sources.”

Additionally, the particulate matter from the blazes can penetrate indoor structures more readily than can the particles from vehicular emissions, which is a cause of concern.

“Staying indoors may not provide protection from smoke particles in the absence of air conditioning or the ability to recirculate filtered indoor air,” says air pollution specialist Constantinos Sioutas, co-director of the Southern California Particle Center.

The paper will be published in Environmental Science and Technology.