Airborne Particles Smuggle Pollutants Worldwide
November 15, 2012

Airborne Particles Smuggle Pollutants Worldwide

DOE/Pacific Northwest National Laboratory

Symbiotic relationship between pollutants and airborne particles explains how city pollution ends up in Arctic

Pollution from fossil fuel burning and forest fires reaches all the way to the Arctic, even though it should decay long before it travels that far. Now, lab research can explain how pollution makes its lofty journey: rather than ride on the surface of airborne particles, pollutants snuggle inside, protected from the elements on the way. The results will help scientists improve atmospheric air-quality and pollution transport models.

The results also show that the particles that envelop pollutants also benefit from this arrangement. The new study in Environmental Science & Technology shows that the airborne particles, made from natural molecules mostly given off by live or burning plants, last longer with a touch of pollutant packed inside. The pollutants are known as polycyclic aromatic hydrocarbons, or PAHs, and are regulated by environmental agencies due to their toxicity.


Floating in the air and invisible to the eye, airborne particles known as secondary organic aerosols live and die. Born from carbon-based molecules given off by trees, vegetation, and fossil fuel burning, these airborne SOA particles travel the currents and contribute to cloud formation. Along for the ride are pollutants, the PAHs, that have long been thought to coat the particles on their surface.


The predictions are based on the assumption that the particles are like liquid spheres, whose fluidity allows PAHs to escape. But they don't escape, and one recent advance has helped to pin down why PAHs are remaining stuck in their particle lairs. Zelenyuk and her colleagues at EMSL, DOE's Environmental Molecular Sciences Laboratory at PNNL, developed an ultra-sensitive instrument that can determine the size, composition and shape of individual particles.












On The Net: