Pacific 2001 Golden Ears Micro Field Study

Prior to Pacific 2001, a weeklong study was conducted at Golden Ears Provincial Park, near Maple Ridge, B.C. The objective of the study was to increase our understanding of the potential contribution to the regional aerosol from the oxidation of monoterpenes. During one particular overnight period, the aerosol mass increased in the presence of higher monoterpene levels with relatively low concentrations of inorganic ions. The particle size distributions began with higher concentrations of smaller particles and ended with lower concentrations of larger particles, indicating evolution due to coagulation and condensation of the terpene oxidation products. The hygroscopic growth factors for these particles, determined from an hTDMA, were relatively small. The growth of water droplets on the particles, in a CCN chamber, showed an initial delay in the growth of the particles, relative to that on particles of sulfate. These two results indicate that these particles were relatively ineffective at taking up water and have consequences for the impact of these particles on visibility in the area as well as the ability to nucleate cloud droplets.