Long-term measurements of volatile organic compounds highlight the importance of sesquiterpenes for the atmospheric chemistry of a boreal forest

摘要: Abstract. The concentrations of terpenoids (isoprene; monoterpenes, MTs; and sesquiterpenes, SQTs) and oxygenated volatile organic compounds (OVOCs; i.e. aldehydes, alcohols, acetates acids, VOAs) were investigated during 2 years at a boreal forest site in Hyytiala, Finland, using situ gas chromatograph mass spectrometers (GC-MSs). Seasonal and diurnal variations terpenoid OVOC as well their relationship with meteorological factors were studied. Of the VOCs examined, C2 – C7 unbranched VOAs showed highest concentrations, mainly due to their low reactivity. terpenoids, MTs showed highest site, but seven different highly reactive SQTs also detected. monthly daily mean concentrations of most aldehydes highly dependent on the temperature. exponential correlation temperature was found for SQT ( β -caryophyllene) summer. diurnal the concentrations could be explained by sources, sinks vertical mixing. The diurnal MT strongly affected vertical mixing. Based correlations mixing layer height (MLH), simple proxies developed for estimating concentrations. To estimate importance compound groups in local atmospheric chemistry, reactivity main oxidants (hydroxyl radical, OH; nitrate NO3 ; and ozone, O3 ) production rates of oxidation products (OxPRs) calculated. MTs dominated OH and radical greatly impacted chemistry, even though 30 times lower than MT concentrations. important of oxidation products. Since show high secondary aerosol (SOA) yields, results clearly indicate local SOA production.