The deposition of polycyclic aromatic hydrocarbons, hexachlorobenzene and polychlorinated biphenyls, dibenzo- p -dioxins and dibenzofurans to a coniferous and a deciduous forest canopy was measured by simultaneously sampling bulk deposition below the canopies and in an adjacent clearing for one year. In addition, ambient air was sampled continuously, with separate analysis of the gaseous and particle-bound phases. The deposition of almost all compounds was higher under the forest canopies than in the clearing. The excess deposition to the forest sites was attributable to equilibrium partitioning between the atmosphere and the canopy vegetation, kinetically limited gaseous deposition, or particle-bound deposition. Which of these deposition processes dominated for a given compound was shown to depend on the octanol–air partition coefficient of the chemical and its gas/particle partitioning. Deposition velocities–to our knowledge the first for SOCs to forests–were calculated by dividing the excess deposition by the air concentrations. The gaseous deposition velocities were 0.78 cm s -1 to the coniferous canopy (annual weighted average) and 3.6 cm s -1 to the deciduous canopy (6 month summer average). These values are high compared to deposition velocities to forest canopies that have been measured for inorganic gases, reflecting the fact that lipophilic organic chemicals are taken up by the leaf/needle cuticle and not just via the stomata. The dry particle bound deposition velocities for particle diffusion and impaction were 0.05 and 0.73 cm s -1 for the coniferous and deciduous canopies, respectively. These values are considerably lower than the gaseous deposition velocities, underlining the importance of gaseous deposition for the accumulation of semivolatile organic compounds in forest ecosystems.
Atmospheric Environment – Elsevier
Published: May 1, 1998
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera