THE BEHAVIOR OF OXYGENATED POLYCYCLIC AROMATIC-HYDROCARBONS ON ATMOSPHERIC SOOT PARTICLES

Outdoor chamber experiments were conducted to assess the atmospheric stability of oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on airborne soot particles. Dilute wood smoke was exposed to midday natural sunlight for periods of 3-4 h in 25-m3 outdoor Teflon film environmental chambers. Aromatic oxygenates such as 9, 10-anthracenedione and cyclopenta[def]phenanthrone appeared to be stable on wood soot particles, while polyaromatic hydrocarbons (PAHs) such as benzo[a]pyrene and benzo[ghi]perylene decayed in sunlight. 1,8-Naphthalic anhydride increased in concentration over the course of the sunlight experiments. In the presence of sunlight and 0.2 ppm photochemically generated ozone, oxy-PAHs declined in concentration and exhibited atmospheric half-lives on wood soot particles that ranged from 80 to 200 min.