Acidic reaction products of monoterpenes and sesquiterpenes in atmospheric fine particles in a boreal forest

Abstract

Abstract. Biogenic acids were measured in aerosols at the SMEAR II (Station for Measuring Forest EcosystemAtmosphere Relations II) station in Finland from June 2010 until October 2011. The analysed organic acids were pinic, pinonic, caric, limonic and caryophyllinic acids from oxidation of α-pinene, β-pinene, limonene, 3 -carene and β-caryophyllene, respectively. Due to a lack of authentic standards, the caric, limonic and caryophyllinic acids were synthesised for this study. The mean, median, maximum and minimum concentrations (ng m −3 ) were as follows: limonic acid (1.26, 0.80, 16.5, below detection limit (< LOD)), pinic acid (5.53, 3.25, 31.4, 0.15), pinonic acid (9.87, 5.07, 80.1, < LOD), caric acid (5.52, 3.58, 49.8, < LOD), and caryophyllinic acid (7.87, 6.07, 86.1, < LOD).The highest terpenoic acid concentrations were measured during the summer. Of the acids, β-caryophyllinic acid showed the highest concentrations in summer, but during other times of the year pinonic acid was the most abundant. The β-caryophyllinic acid contribution was higher than expected, based on the emission calculations of the precursor compounds and yields from oxidation experiments in smog chambers, implying that the β-caryophyllene emissions or β-caryophyllinic acid yields were underestimated. The concentration ratios between terpenoic acids and their precursors were clearly lower in summer than in winter, indicating stronger partitioning to the aerosol phase during the cold winter season. The β-caryophyllinic and caric acids were weakly correlated with the accumulation-mode particle number concentrations.

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

“…Among the pinene derived oxidation products, MBTCA (3-methyl-1,2,3-butanetricarboxylic acid) was observed to be the most abundant individual monoterpene oxidation product, with concentrations of up to 73 ng m −3 , followed by pinonic acid with a maximum concentration of 46 ng m −3 (van Eijck, 2013). Interestingly, these concentrations are in the same range as monoterpene oxidation products measured during summertime in boreal forest environments (Vestenius et al, 2014), ecosystems which are known to strongly emit monoterpenes. However, these observations of high monoter- pene product concentrations match with the high monoterpene mixing ratios measured at the same site (Yáñez-Serrano et al, 2015).…”

“…Very few measurements exist of sesquiterpene oxidation product concentra- tions and actually none in tropical forests, which complicates a comparison. Measurements in boreal ecosystems (Vestenius et al, 2014) showed mean summertime concentrations of caryophyllinic acid (one of the β-caryophyllene oxidation products) of about 8 ng m −3 , which is a high concentration for a single compound compared to the concentrations measured at ATTO, where the measured concentration range of caryophyllinic acid is 0.26-1.38 ng m −3 . In summary, the contribution of monoterpene oxidation products to SOA at ATTO is relatively high and essentially comparable with their contribution to boreal forest SOA, whereas the contribution of sesquiterpene products is much less (about 1/10) than in boreal forest ecosystems.…”

Nanoparticle growth by particle-phase chemistry

“…Table 1 gives relevant molecular parameters and gas-phase mixing ratios. The gas-phase mixing ratios are assumed to be constant over time (steady state) as might be achieved in a flow reactor, and the values chosen are typical of what might be observed during NPF in a boreal forest (Vestenius et al, 2014). Molecular volatility is expressed in terms of the saturation concentration, C * , which is the equilibrium vapor pressure in units of µg m −3 (Donahue et al, 2006).…”

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

“…In the growing season, forested boreal regions emit biogenic volatile organic compounds (BVOCs) (isoprene, terpenes and sesquiterpenes) into the atmosphere (Kourtchev et al, 2005;Ehn et al, 2012;Noe et al, 2012;Ebben et al, 2011;Vestenius et al, 2014), and their oxidation products contribute to SOA formation or condense onto already 14382 E. F. Mikhailov et al: Long-term measurements (2010-2014 formed particles during transport, increasing aerosol sizes and mass (Tunved et al, 2006;Hallquist et al, 2009;Liao et al, 2014). Since the emission of the organic particle precursors depends on air temperature (Isidorov et al, 1985;Lappalainen et al, 2009), the SOA mass concentration also positively correlates with temperature (Leaitch et al, 2011;Corrigan et al, 2013;Liao et al, 2014).…”