Atmospheric concentrations and temporal variations of C1C3 carbonyl compounds at two rural sites in central Ontario

Abstract

AIIIttact-Measurements of formaldehyde, acetaldehyde, acetone and propionaldehyde concentrations were made at two rural sites in central Ontario. One site (at Egbert, Ont.) is located~60 km northwest of Toronto, while the other site <at Dorset, Ont.) is~150 km northeast of the Egbert site. Measurements were made using a modified version of a derivatization technique in which sample air is pumped through Tefton tubes packed with silica gel that is coated with 2,4-dinitrophcnylhydrazine (DNPH). The product hydrazones were separated and quantified using HPLC. Quantitative determinations of formaldehyde, acetaldehyde and acetone were made for 49 and 47 samples at the Dorset and Egbert sites, respectively, between 2S July and 30 August 1988. The average concentrations determined at the Dorset site for formaldehyde, acetaldehyde, and acetone were 1.6, 0.46 and 1.8 ppb, respectively, and for the Egbert site the corresponding averages were 1.8,0.57 and 1.6 ppb. Aset of 10 samples from the Egbert site were analysed for propionaldehyde yielding an average concentration of 0.03 ppb. The formaldehyde measurements were compared with measurements made at the same time using Tunable Diode Laser Absorption Spectroscopy. The observed concentrations reported here are compared with previously reported measurements of these species and interpreted in terms of atmospheric variables (e.g. meteorology, concentrations of precursor hydrocarbons) influencing their concentrations.

Seasonal, diurnal and nocturnal variations of carbonyl compounds in the semi-urban environment of Orléans, France

“…The levels of atmospheric carbonyls measured in different areas are listed in Table 5 Canada reported by Shepson et al (1991) and in a background site of UST, Hong Kong reported by Cheng et al (2014), but significantly lower than those reported in urban areas in the world (Pang and Mu 2006;Feng et al 2005;Moussa et al 2006;Kalabokas et al 1988;Possanzini et al 1996).…”

“…The ratio of formaldehyde/acetaldehyde (C1/C2) has been widely used as an indicator of a biogenic source for formaldehyde (Shepson et al 1991). C1/C2 ratios were reported to vary from about 1 in urban areas (Ho et al 2002;Feng et al 2005;Pang and Mu 2006;Xu et al 2010) to about 10 in deciduous forests (Jacob and Wofsy 1988;Shepson et al 1991).…”

“…C1/C2 ratios were reported to vary from about 1 in urban areas (Ho et al 2002;Feng et al 2005;Pang and Mu 2006;Xu et al 2010) to about 10 in deciduous forests (Jacob and Wofsy 1988;Shepson et al 1991). This high value of C1/C2 ratio implies that the photo-oxidation of biogenic hydrocarbons such as isoprene yields more formaldehyde than acetaldehyde (Lloyd et al 1983;Shepson et al 1991;Duane et al 2002).…”

“…C1/C2 ratios were reported to vary from about 1 in urban areas (Ho et al 2002;Feng et al 2005;Pang and Mu 2006;Xu et al 2010) to about 10 in deciduous forests (Jacob and Wofsy 1988;Shepson et al 1991). This high value of C1/C2 ratio implies that the photo-oxidation of biogenic hydrocarbons such as isoprene yields more formaldehyde than acetaldehyde (Lloyd et al 1983;Shepson et al 1991;Duane et al 2002). As listed in Table 4, the average C1/C2 ratio in this study was in good agreement with that reported by Villanueva-Fierro et al (2004), who conducted measurement at rural areas near a forest in Mexico, but evidently greater than those measured at urban areas (Tanner et al 1988;Grosjean et al 1996;Possanzini et al 2000;Xu et al 2010;Lü et al 2010), indicating that the photo-oxidation of biogenic hydrocarbons played an important role in atmospheric carbonyl formation at the sampling site.…”

“…To evaluate their influence on human health as well as atmospheric chemistry, field measurements of atmospheric carbonyls have been carried out in different areas, including urban (Cheng et al 2014;Lü et al 2010;Weng et al 2009;Pang and Mu 2006;Pang and Lee 2010;Xu et al 2010;Zhang et al 2012;Feng et al 2005;Ho et al 2002;Nguyen et al 2001;Possanzini et al 2002), rural (Xie et al 2008;Villanueva-Fierro et al, 2004;Wiedinmyer et al 2001;Solberg et al 2001;Shepson et al 1991;Cheng et al 2014) and remote areas (Singh et al 2004;Zhou and Mopper 1993;Wagner et al 2001;De Serves 1994). In comparison with urban areas, however, investigations on atmospheric carbonyls in rural or semi-urban areas are still sparse.…”