Airborne pollutants lead a double life
Researchers at Harvard University and the University of British Columbia (UBC) have provided visual evidence that atmospheric particles — which are ubiquitous, especially above densely populated areas — separate into distinct chemical compositions during their life cycle. The observations could have important implications for modeling global climate change and predicting air quality conditions. The tiny particles, which form part of an airborne chemical mix above cities, play a role in pollution (by providing a surface for chemical reactions) and in climate (by reflecting and absorbing solar radiation and by acting as seed surfaces for water condensation and cloud formation). “We’ve confirmed experimentally that changes in relative humidity can separate the organic and inorganic material in individual atmospheric particles into distinct liquid phases, much like oil separates from water,” says UBC Associate Professor Allan Bertram, director of the collaborative research and training program on atmospheric aerosols at UBC and co-principal investigator on the...