Water‐soluble organic components in aerosols associated with savanna fires in southern Africa: Identification, evolution, and distribution

Abstract

[1] During the SAFARI 2000 field campaign, both smoke aerosols from savanna fires and haze aerosols in the boundary layer and in the free troposphere were collected from an aircraft in southern Africa. These aerosol samples were analyzed for their water-soluble chemical components, particularly the organic species. A novel technique, electrospray ionization-ion trap mass spectrometry, was used concurrently with an ion chromatography system to analyze for carbohydrate species. Seven carbohydrates, seven organic acids, five metallic elements, and three inorganic anions were identified and quantified. On the average, these 22 species comprised 36% and 27% of the total aerosol mass in haze and smoke aerosols, respectively. For the smoke aerosols, levoglucosan was the most abundant carbohydrate species, while gluconic acid was tentatively identified as the most abundant organic acid. The mass abundance and possible source of each class of identified species are discussed, along with their possible formation pathways. The combustion phase of a fire had an impact on the chemical composition of the emitted aerosols. Secondary formation of sulfate, nitrate, levoglucosan, and several organic acids occurred during the initial aging of smoke aerosols. It is likely that under certain conditions, some carbohydrate species in smoke aerosols, such as levoglucosan, were converted to organic acids during upward transport.

Measurements of aerosol size‐resolved hygroscopicity at sub and supermicron sizes

“…The identification of the fire plume is unequivocal, based on both HYSPLIT back trajectory and aerosol levoglucosin concentrations an order of magnitude higher than any others encountered during the study [cf. Gao et al, 2003]. A DHGF spectrum obtained in this plume on August 13th (flight 813) is shown in Figure 4, together with that from the polluted plume of flight 818 and the average marine spectrum.…”

“…[10] In addition to the physical measurements, limited data on the aerosol chemical composition are available in the form of bulk filter samples, analyzed as described by Gao et al [2003], and individual particle analysis from SEM substrates, analyzed as described by Laskin et al [2003].…”

Haze in the Klang Valley of Malaysia

“…Also, note that oxalate is an organic acid associated with biomass burning. Oxalic acid is produced from the combustion of the cellulose material in vegetation (Gao et al 2003).…”

Determination of biomass burning tracers in air samples by GC/MS

“…Biomass combustion in fireplaces, residential, campfires and wildfires emits wood smoke which is a main source of soot, particulate matter (PM), free radicals, irritants and other chemicals which can be toxic or mutagenic [1][2][3][4][5]. The atmospheric aerosol formed can scatter or absorb incoming solar radiation, change visibility impairments and modify cloud formation processes [6][7][8][9].…”

“…Gas chromatography coupled with mass spectrometry detector (GC/MS) is usually use to determine the LG in wood smoke, PM, ashes, soil and sediment samples [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]23] but other techniques as high performance liquid chromatography with aerosol charge detection (HPLC-ACD), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) or capillary electrophoresis with pulsed amperometric detection (CE-PAD) are also applied. The GC determination of levoglucosan consist of extraction, derivatization -mainly based on silylation giving trimethylsilyl ether derivative to reduce its polarity, same increase its volatility and analysis.…”