• Number 331  |
• February 21, 2011

No longer pining for organic molecules to make particles in the air

The fresh scent of pine has helped scientists find missing sources of organic molecules in the air — which, it could well turn out, aren’t missing after all. Scientists at DOE’s Pacific Northwest National Laboratory and Imre Consulting discovered the particles, known as secondary organic aerosols (SOA), aren’t liquid droplets. Instead, these particles are solid and evaporate more than 100 times slower than expected, never equilibrating with their surroundings.

Evaporation of SOA takes days, not seconds, as researchers previously assumed. These findings present a very different picture of SOA and call for a significant change in the way these aerosols are represented in air-quality models.

"This work could resolve the discrepancy between field observations and models," said principal investigator Dr. Alla Zelenyuk, a chemist at PNNL. "The results will affect how we represent organics in climate and air quality models, and could have profound implications for the science and policy governing control of submicron particulate matter levels in the atmosphere."

This research was funded by DOE’s Office of Basic Energy Sciences and Office of Biological and Environmental Research. The research was done in EMSL, a national scientific user facility.

[Kristin Manke, 509.372.6011,
kristin.manke@pnl.gov]