Emissions of formaldehyde, acetic acid, methanol, and other trace gases from biomass fires in North Carolina measured by airborne Fourier transform infrared spectroscopy

Abstract

Abstract. Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (F'FIR) coupled to a "flow-through" multipass cell (AFrlR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO2; and integrated filter and canister samples. AFrlR spectra acquired within a few kilometers of the fires yielded excess mixing ratios for 10 of the most common trace gases in the smoke: water, carbon dioxide, carbon monoxide, methane, formaldehyde, acetic acid, formic acid, methanol, ethylene, and ammonia. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were each 2.5 _+ 1%. This is in excellent agreement with (and confirms the relevance of) our results from laboratory fires. However, these ratios are significantly higher than the emission ratios reported for these compounds in some previous studies of "fresh" smoke. We present a simple photochemical model calculation that suggests that oxygenated organic compounds should be included in the assessment of ozone formation in smoke plumes. Our measured emission factors indicate that biomass fires could account for a significant portion of the oxygenated organic compounds and HOx present in the tropical troposphere during the dry season. Our fire measurements, along with recent measurements of oxygenated biogenic emissions and oxygenated organic compounds in the free troposphere, indicate that these rarely measured compounds play a major, but poorly understood, role in the HOx, NOx, and 03 chemistry of the troposphere.

A Chemical Ionization Mass Spectrometer for ambient measurements of Ammonia

“…Global NH 3 emission data taken with infrared satellite observations show that concentrations in the eastern United States are low and no significant hotspots exist in this region (Clarisse et al, 2009 (Dentener and Crutzen, 1994) and [NH 3 ] up to 430 ppbv have been seen in strong point source locations (Schlesinger and Hartley, 1992). Emission measurements made in different automobile tunnels have shown [NH 3 ] of 50-400 ppbv (Fraser and Cass, 1998;Kean et al, 2000;Moeckli et al, 2004) [NH 3 ] of 20-70 ppbv have also been reported from smoke (Yokelson et al, 1999Goode et al, 2000), as well as 100-200 ppbv in biomass burning plumes (Hurst et al, 1994;Li et al, 2006).…”

Emissions from forest fires near Mexico City

“…The AFTIR was used for continuous measurements of water vapor (H 2 O), carbon dioxide (CO 2 ), carbon monoxide (CO), and methane (CH 4 ); or to grab samples for signal averaging and measurement of H 2 O, CO 2 , CO, nitric oxide (NO), nitrogen dioxide (NO 2 ), ammonia (NH 3 ), hydrogen cyanide (HCN), CH 4 , ethene (C 2 H 4 ), acetylene (C 2 H 2 ), formaldehyde (HCHO), methanol (CH 3 OH), acetic acid (CH 3 COOH), formic acid (HCOOH), and ozone (O 3 ). The details and the accuracy of the AFTIR technique are described by Yokelson et al (1999Yokelson et al ( , 2003a.…”

Carbon isotopic signatures of methanol and acetaldehyde emitted from biomass burning source

“…[4] Biomass burning is an important source of atmospheric OVOCs [e.g., Holzinger et al, 1999;Yokelson et al, 1999]. In this study, we characterized the first carbon isotope signatures of methanol and acetaldehyde emitted from biomass burning sources (BB) and elucidated factors controlling their variation using small chamber burning experiments of five plant materials (three C 3 and two C 4 plants).…”