Measurement of terpenes and other organics in an Adirondack Mountain pine forest

Abstract

The total terpene concentration beneath the canopy of an eastern United States coniferous forest was found to be of the order of 50 μg/m3. Similar measurements within the forest but outside the canopy ranged from 3 to 32 μg/m3. Two samples collected at a mountain summit above the tree line were found to contain 7 and 27 μg/m3 total terpenes. Downwind from the coniferous forest in an area of deciduous vegetation the mean morning total terpene level was 4 μg/m3 and increased to 11 μg/m3 during the afternoon. Unidentified species, primarily in the C5–C9 range, were observed in total concentrations which averaged approximately twice the sample total terpene value. Results indicate a concentration range of 8–130 μg/m3 for C5–C10 organics in rural atmospheres in the Adirondack Mountain region of New York State. It is concluded that the majority of observed organics are of natural origin.

A smog chamber for studies of the reactions of terpenes and alkanes with ozone and OH

“…It is estimated that these biogenic emissions are in the order of or even may exceed anthropogenic sources (Zimmerman et al, 1978;Dimitriades, 1981). In contrast to these estimates, the actually measured concentrations right near the sources in the canopy are only in the ppb range (Graedel, 1979;Whitby and Coffey, 1977). Since almost all terpenes are unsaturated compounds, they are not only affected by OH.…”

Volatile organic compounds in seawater

“…The major compounds are alpha and beta pinene and limonene (Rasmussen, 1972). Air measurements within forests have shown total terpene levels of 50 ng!liter-air (Whitby and Coffey, 1977). Downwind from the forest, levels between 4 and 11 ng/liter were observed.…”

“…Several workers have shown that land plants produce and release tremendous quantities of terpenes (ten carbon branched and cyclic unsaturated hydrocarbons) (Went, 1960;Rasmussen and Went, 1965;Rasmussen, 1972;Tyson eta!., 1974;Whitby and Coffey, 1977). It has been estimated that 2-4 x I08 metric tons of terpenes are released annually (Rasmussen and Went, 1965;Rasmussen, 1972) to the atmosphere.…”

“…Seasonal variations in the outputs of volatile organic compounds such as the terpenes (Whitby and Coffey, 1977) and their subsequent transport into coastal seawater may be expected.…”

Higher Molecular Weight Terpenoids as Indicators of Organic Emissions from Terrestrial Vegetation

“…Monoterpenoids are emitted in large amounts by vegetation and generally are comprised mainly of pinenes, carenes, camphenej sabinene, P-phellandrene and terpinolene. Field measurements of monoterpenoids present in the atmosphere of rural and agricultural areas have been reported (25,27,31,44,(71)(72)(73)(74)(75). Emissions inventories for biogenic monoterpenoids for the continental U.S. are available (9)(10)(11)(12)(13).…”