Wood Processing As A Source Of Terpene Emissions Compared To Natural Sources
Free (open access)
K. M. Granström
The aim of this paper is to analyse the importance of terpene emissions from forestry and the wood industry and relate these anthropogenic emissions to the natural terpene emissions from undisturbed forests. Biogenic volatile organic compounds are emitted naturally from trees and other plants. Boreal forests are dominated by terpene-emitting tree species. Anthropogenic terpene emissions occur due to drying, machining and tooling of wood. This is a cause of concern with regulatory authorities faced with expanding production of biofuels, e.g. wood pellets. Anthropogenic terpene emissions are of current importance as the use of biofuels has increased considerably over the recent years. The most important environmental effects of terpene emissions are due to the formation of photo-oxidants and atmospheric aerosols. Photo-oxidants cause forest and crop damage, and are harmful to humans. Carbonaceous aerosols have an impact on climate change. Furthermore, most sesquiterpenes are used in the chemical communication systems of various insects. There are also issues concerning the working environment in the wood industry. Environmental effects of terpene emissions are analysed with focus on three key aspects: the total amount of emissions, the concentration in air and the types of terpenes emitted. The reported concentrations of monoterpenes are in most cases below the occupational exposure limits, with drum barking and pellets production from non-dried sawdust close to the limit. Anthropogenically emitted terpenes have a higher proportion of sesquiterpenes than naturally emitted terpenes have, especially when the processing of wood involves elevated temperatures. Keywords: terpenes, VOC, spruce, pine, sawmill, drying, wood, biofuel, pellets, sawdust.
terpenes, VOC, spruce, pine, sawmill, drying, wood, biofuel, pellets, sawdust.