Diurnal changes in the distribution of dicarboxylic acids, ketocarboxylic acids and dicarbonyls in the urban Tokyo atmosphere

Abstract

Secondary organic aerosol in the urban atmosphere is an important issue from a viewpoint of not only air pollution but also regional and global atmospheric environment. To better understand the production of water-soluble organic aerosols, we analyzed atmospheric particles collected in time-series in Tokyo for dicarboxylic acids (C2-C10), ketocarboxylic acids (C2-C4) and a-dicarbonyls (C2-C3) using a GC and GC/MS. Here, we report, for the first time, diurnal distributions of dicarboxylic acids, ketoacids and dicarbonys in the urban atmosphere. Oxalic acid was found as the most abundant species, followed by malonic, succinic, pyruvic and glyoxylic acids. Total diacids showed a concentration maximum in daytime (11-14 h) with a dynamic change in their molecular composition especially in summer samples. Relative abundances of unsaturated (maleic, methylmaleic and phthalic) and some saturated (methylsuccinic and adipic) species increased in the morning (8-11 h) whereas those of oxalic acid decreased down to 35 % in 8-11 h but increased up to 58 % toward 17-20 h. The diurnal variations are interpreted by photochemical production of diacids, where unsaturated and some saturated species are preferentially generated early in the morning via photo-oxidation of aromatic hydrocarbons and cyclic olefins and further oxidized to oxalic acid in the afternoon

Diurnal and temporal variations of water-soluble dicarboxylic acids and related compounds in aerosols from the northern vicinity of Beijing: Implication for photochemical aging during atmospheric transport

“…Thus C 6 /C 9 ratio has been utilized as a tracer to estimate the anthropogenic v.s. biogenic contributions to organic aerosols (Kawamura and Yasui, 2005). In the present study, C 6 /C 9 ratios present greater values during daytime (0.5-2.0, av.…”

“…Generally, TC concentrations and their proportions in aerosol mass should be controlled by emission strengths, photochemical processing and/or dilution by inorganic species. TC values and their proportions to aerosol masses in Mangshan are smaller than those (49 µg m -3 , 17%) reported from Beijing (Sekine et al, 1992) and those (24 µg m -3 , 21%) from Tokyo (Kawamura and Yasui, 2005), but are significantly greater than those (0.38 µg m -3 , 0.75%) reported in the remote marine aerosols from the Pacific (Kawamura and Sakaguchi, 1999), in which sea-salts are abundant.…”

“…29 ng m -3 ) from urban Tokyo in summer (Kawamura and Yasui, 2005). However, they are lower than those (90 ng m -3 ) from Chinese cities (Ho et al, 2007).…”

“…An increased C 2 /total diacid ratio has been reported in the marine aerosols from the Pacific during the long-range atmospheric transport (Kawamura and Sakaguchi, 1999a) and used as a proxy of photochemical aging of organic aerosols (Kawamura and Yasui, 2005). Interestingly, the ratios of C 2 /total diacids are generally higher in nighttime than daytime ( Figure S2d), probably due to the preferential production of oxalic acid in nighttime via the oxidation of its precursors in the aerosol particles.…”

Effects of Land Reclamations in Osaka Bay on the Regional Climate

“…Kawamura (1979) and Mikami (2003) showed that the increasing rate of T min was greater than that of T max from the data at the Tokyo observatory from 1876 to 1970 and from 1900 to 2000, respectively, thus indicating a decrease in DTR by the effects of urbanization. Kondo (2009) estimated the effects of urbanization on temperature by using a simple one-dimensional boundary layer model.…”