Emission Factors of Particulate Matter and Elemental Carbon for Crop Residues and Coals Burned in Typical Household Stoves in China

Abstract

Both particulate matter (PM) and black carbon (BC) impact climate change and human health. Uncertainties in emission inventories of PM and BC are partially due to large variation of measured emission factors (EFs) and lack of EFs from developing countries. Although there is a debate whether thermal-optically measured elemental carbon (EC) may be referred to as BC, EC are often treated as the same mass of BC. In this study, EFs of PM (EFPM) and EC (EFEC) for 9 crop residues and 5 coals were measured in actual rural cooking and coal stoves using the carbon mass balance method. The dependence of the EFs on fuel properties and combustion conditions were investigated. It was found that the mean EFPM were 8.19 ± 4.27 and 3.17 ± 4.67 g/kg and the mean EFEC were 1.38 ± 0.70 and 0.23 ± 0.36 g/kg for crop residues and coals, respectively. PM with size less than 10 μm (PM10) from crop residues were dominated by particles of aerodynamic size ranging from 0.7 to 2.1 μm, while the most abundant size ranges of PM10 from coals were either from 0.7 to 2.1 μm or less than 0.7 μm. Of various fuel properties and combustion conditions tested, fuel moisture and modified combustion efficiency (MCE) were the most critical factors affecting EFPM and EFEC for crop residues. For coal combustion, EFPM were primarily affected by MCE and volatile matter, while EFEC were significantly influenced by ash content, volatile matter, heat value, and MCE. It was also found that EC emissions were significantly correlated with emissions of PM with size less than 0.4 μm.

Measurements of emission factors of PM2.5, OC, EC, and BC for household stoves of coal combustion in China

“…If take no account of the impact of coal maturity, EF PM measured in the present study shows a high comparability with previous measurement results. For example, Shen et al suggested a mean EF PM value of 3.17 ± 4.67 g/kg for five coals in typical household stoves (Shen et al, 2010), close to the total average of 3.69 ± 2.48 g/kg for all combinations in this experiment.…”

“…As shown in Table S2, the present EF values are somewhat lower than previous measurement results by our group and Zhang et al (Chen et al, 2005(Chen et al, , 2006Zhang et al, 2008;Zhi et al, 2008) but higher than those by Shen et al (Shen et al, 2010). The main reason may point to the different selection of coal types and stove conditions, which suggests that much more measurements need to be conducted by considering all kinds of typical coal/stove combinations, especially those actually used in rural kitchens (Shen et al, 2013b).…”

“…This inspired a number of studies on the measurements about emission factor (EF) of BC for coal combustion in household stoves in China in the last decade, which is important data for assessing its emission inventory (Bond et al, 2004a;Cao et al, 2006;Lei et al, 2011;Ohara et al, 2007;Streets et al, 2003Streets et al, , 2001Wang et al, 2012;Zhang et al, 2009). Those studies show variation up to several orders of magnitude of EFs of BC and other pollutants among different coal/stove combinations in China's household sector (Chen et al, 2005(Chen et al, , 2006Shen et al, 2013b;Shen et al, 2010;Zhang et al, 2000Zhang et al, , 2008Zhi et al, 2008).…”

Household fuel use for cooking and heating in China: Results from the first Chinese Environmental Exposure-Related Human Activity Patterns Survey (CEERHAPS)

“…Also, it is important to note that although our results indicate that the proportion of solid-fuel users decreased from 1991 to 2012, since the overall population in China increased significantly (from 1.16 billion in 1991 to 1.35 billion in 2012), the absolute number of people using solid fuels was still extremely large (Table S2). This suggests that a significant number of people are potentially exposed to harmful pollutants, and consequently at high risk for the development of disease, as inefficient burning of solid fuels often yield a large number of incomplete pollutants [18][19][20].…”

Spatial distribution of black carbon emissions in China

“…Compared with other locally measured results [35,36] and emission factors from foreign studies [19], Chen et al's results were adapted and used in this work. Li et al [37] obtained emission factors for crop residues and firewood for typical rural areas in China, and Shen et al [38] and Cao et al [39] developed crop residue emission factors using actual and simulative stoves. The emission factors for biofuels in our work were deduced from the above researches; for example, the geometric mean of the three factors named above was used as the emission factor of crop residues.…”