Viscosity, diffusion, and mixing times in secondary organic aerosol

28 Apr
Atmospheric & Environmental Chemistry Seminar
Allan Bertram, UBC
Friday, April 28, 2017 -
12:00pm to 1:00pm
100F Pierce Hall

Secondary organic aerosol (SOA) can modify Earth’s climate by scattering and absorbing solar

radiation and by modifying the properties of clouds. SOA can also negatively affect air quality

and reduce visibility in urban environments. To predict the role of SOA in climate, air quality

and visibility, a good understanding of viscosity, diffusion, and mixing times within SOA

particles is required. Our research has shown that viscosity, diffusion, and mixing times within

SOA particles depend strongly on relative humidity, and at low relative humidities the viscosity

of SOA particles can be as high as the viscosity of bitumen. In addition, more recently we have

shown that the mixing times within alpha-pinene SOA particles is most often less than 1 hour in

the planetary boundary layer. On the other hand, in the free troposphere the mixing times within

these particles is often greater than 1 hour, with implications for modelling SOA evolution.

Zhaoheng Gong