Absorption of Atmospheric Formaldehyde by Deciduous Broad-Leaved, Evergreen Broad-Leaved, and Coniferous Tree Species

Abstract

Abstract To estimate the effect of tree planting on atmospheric formaldehyde, the absorption of formaldehyde by various tree species was examined. The absorption rates varied from 8.6 (Japanese black pine) to 137 ng dm−2 h−1 ppb−1 (Lombardy poplar) at 1000 μmol of photons m−2 s−1, and the absorption rate increased in the following order: deciduous broad-leaved tree species > evergreen broad-leaved tree species > coniferous tree species. In experiments in which the light intensity was varied, a linear relationship between the formaldehyde absorption rate and the transpiration rate was observed for three tree species. From the results obtained from a simplified gas diffusive resistance model, we can conclude that formaldehyde is absorbed through the stomata, and is rapidly metabolized by three tree species. Even at a high concentration of about 2000 ppb, trees have the ability to absorb atmospheric formaldehyde for at least 8 h without any visible foliar injury. We conclude that trees in general could act as an important sink for atmospheric formaldehyde.