Hygroscopic organic aerosols during BRAVO?
The hygroscopic properties of the organic fraction of aerosols are poorly understood. The ability of organic aerosols to absorb water as a function of relative humidity (RH) was examined using data collected during the 1999 Big Bend Regional Aerosol and Visibility Observational Study (BRAVO). (On average, organics accounted for 22% of fine particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5) mass). Hourly RH exceeded 80% only 3.5% of the time and averaged 44%. BRAVO aerosol chemical composition and dry particle size distributions were used to estimate PM2.5 light scattering (Bsp) at low and high ambient RH. Liquid water growth associated with inorganic species was sufficient to account for measured Bsp for RH between 70 and 95%.
Lowenthal
Douglas H
DH
Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada 89512, USA. dougl@dri.edu
Kumar
Naresh
N
Hand
Jenny
J
Day
Derek
D
Kreidenweis
Sonia
S
Collett
Jeffrey
J
Lee
Taehyoung
T
Ashbaugh
Lowell
L
D000327:Adsorption; D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D008962:Models, Theoretical; D009930:Organic Chemicals; D014867:Water / Q000737:chemistry
D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D014867:Water