Laboratory measurements of smoke optical properties from the burning of Indonesian peat and other types of biomass

Abstract

[1] We present the first results on optical properties (l $ 540 nm) of fresh aerosols from the combustion of Indonesian peat, German peat and other types of biomass, measured under controlled laboratory conditions. The mass scattering and mass absorption efficiencies for Indonesian and German peat aerosols are in the range of 6.0-8.1 and 0.04 -0.06 m 2 g À1 , respectively. A very high single scattering albedo (0.99) is observed for the peat smoke aerosols, reflecting the smoldering burning conditions (emission ratio, DCO/DCO 2 = 19 -50%). The relative increase in light scattering (f(RH)) due to an increase in relative humidity (RH) from 15% to 90% is very low (i.e., f(90) = 1.05) for both Indonesian and German peat aerosols. This value is considerably smaller than for aged Indonesian peat smoke particles (f(80) = 1.65) [Gras et al., 1999]. This suggests that atmospheric aging processes may be an important factor for aerosol hygroscopicity.

Observing and understanding the Southeast Asian aerosol system by remote sensing: An initial review and analysis for the Seven Southeast Asian Studies (7SEAS) program

“…Burns with low sulfate, but high co-emission of SO 2 , could increase in ionic mass fraction from secondary mass production during smoke particle evolution as shown in Fig. 10a of Yokelson et al (2009), thus increasing hygroscopicity in time, (such as suggested by Chand et al, 2005 andDusek et al, 2005 with support from Kotchenruther and Hobbs, 1998). Indeed, we know that many facets of smoke evolution are rapid and extensive.…”

“…It is widely believed that owing to the volcanic nature of region, sulfur loads in the peat and soils are high, which results in the high SO 2 and sulfate emissions (Langmann and Graf, 2003). Chand et al (2005), however, extensively examined the properties of Sumatran peat smoke in the laboratory as well. As expected (Reid et al, 2005a), as peat combustion is largely smoldering they derived high mass scattering efficiencies ; ω o =0.99).…”

Water uptake by fresh Indonesian peat burning particles is limited by water-soluble organic matter

“…A field observation of water uptake properties of Indonesian biomass burning plumes also demonstrated that these particles are hygroscopic, with a median hygroscopic growth in light scattering (f (RH)) of 1.65 between 20 and 80 % relative humidity (RH) (Gras et al, 1999). On the other hand, freshly emitted Indonesian peat burning particles generated in a laboratory were suggested to be non-hygroscopic with respect to quite a low f (RH) = 1.05 at 90 % RH (Chand et al, 2005), and they were almost CCN inactive especially for particles larger than 150 nm (equivalent to κ = 0.05 for 100 nm particles, calculated with an assumed surface tension of 0.072 N m −1 at 25 • C) (Dusek et al, 2005). The uniqueness of water uptake properties of freshly emitted Indonesian peatland burning particles as well as the discrepancy between the previously reported laboratory and field data needs to be consistently understood based on their chemical compositions for accurate evaluation on the environmental impacts.…”

“…Water uptake properties of biomass burning particles, including those emitted from peatlands, have been explored in a laboratory through measurements of hygroscopic growth and CCN activity (Chand et al, 2005;Dusek et al, 2005Dusek et al, , 2011Day et al, 2006;Petters et al, 2009;Carrico et al, 2010). In general, freshly emitted biomass burning particles have been found to be hygroscopic.…”

Water vapor release from biomass combustion

“…Here we report on a re-analyzed data set, which originally had been produced to investigate aerosol formation from biomass combustion (Wurzler et al, 2001;Dusek et al, 2004;Parmar et al, 2004;Zeromskiene et al, 2004;Chand et al, 2005;Dusek et al, 2005;Hungershoefer et al, 2005;Schmid et al, 2005;Hungershoefer et al, 2008;Iinuma et al, 2007).…”