Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency

Abstract

Abstract. We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

Air Quality Impacts of Smoke from Hazard Reduction Burns and Domestic Wood Heating in Western Sydney

“…Comparing the enhancement ratios estimated here (using the preferred linear regression method) with emission ratios from previous studies of Australian forest fires smoke composition [21,23,29,33] (see Table 5), most enhancement ratios, ER i/CO from this study are between 2 and 3 times lower than emission ratios reported in the literature.…”

“…The consequences of inhaled wood-smoke on human health (predominantly on the cardio-vascular system) are well documented in the literature (e.g., References [7][8][9][10][11]). Numerous studies have been undertaken to characterize the chemical composition of smoke from Australian fires ( [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]) and the impacts of these fires on air quality in Australian cities (e.g., References [4,5,10,30]). There have been relatively few studies looking at the composition of wood-smoke pollution from domestic wood heaters in Australia and focus has been predominantly on rural communities, where this source dominates above all others [31][32][33].…”

Gas-phase pyrolysis products emitted by prescribed fires in pine forests with a shrub understory in the southeastern United States

“…In addition to those laboratory studies, a number of field campaigns have also used FTIR spectroscopy to identify trace gases from prescribed fires (Akagi et al, 2013(Akagi et al, , 2014Burling et al, 2011;Goode et al, 2000;Yokelson et al, 1999;Wooster et al, 2011;Alves et al, 2010;Hurst et al, 1994a, b;Paton-Walsh et al, 2008Guérette et al, 2018). Studies that have the ability to measure emissions both near the fire and aloft are especially useful in understanding the complex chemistries that occur during and after prescribed fires, including the (oxidative) chemistry of the downwind plume.…”

Understanding Spatial Variability of Air Quality in Sydney: Part 1—A Suburban Balcony Case Study

“…The WASPSS-Auburn campaign incorporated a mobile air quality monitoring station and an open-path infrared Fourier transform spectrometer (OP-FTIR). The OP-FTIR system, which can measure infrared active gases such as CO, NH 3 , N 2 O and CH 4 , has previously been deployed for agricultural [28][29][30] and biomass burning [31,32] emissions estimates. Details of the main findings from the OP-FTIR during WASPSS, which relate to vehicle ammonia emissions and episodes of significant smoke pollution, are presented in two separate papers [33,34].…”