Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico
Trace gas and particle emissions from domestic and industrial biofuel use and garbage burning in central Mexico
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DOI：
10.5194/acp-10-565-2010
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发表时间：
2010-01-01
影响因子：
6.3
通讯作者：
Hsu, S. -C.
中科院分区：
文献类型：
--
作者：
Christian, T. J.;Yokelson, R. J.;Hsu, S. -C.
在墨西哥中部，在2007年春季，我们测量了12种气体的初始排放量和气溶胶形态元素和有机碳（EC，OC），脱水糖，Cl-，NO3-，和20种金属从10个烹饪火灾，4个垃圾火灾，3个制砖窑，3个木炭制造窑，和两个作物残留物火灾。据估计，全球生物燃料的使用量超过2600 Tg/y。通过几个简单的案例研究，我们表明，在发展中国家，烹饪火灾可能是几种气体和细颗粒物的主要来源。带有烟囱的隔热炉灶早些时候被证明可以减少室内空气污染和每次烹饪任务的燃料使用。我们证实，它们还将单位质量燃料燃烧的VOC污染物排放量减少了约一半。我们没有在墨西哥或非洲检测到烹饪火灾的HCN排放。因此，如果区域来源的归属是基于其他类型生物质燃烧（BB）的典型HCN排放量，那么在许多发展中国家，生物燃料的使用和总的BB将被低估。这一点也很重要，因为从太空中无法探测到烹饪火灾。我们估计，全球每年产生的垃圾量约为2000 Tg，其中约一半可能被焚烧，这使其成为一个通常被忽视的全球主要排放源。我们估计垃圾燃烧的细颗粒物排放因子（EFPM2.5）类似于10.5 +/- 8.8 g/kg，这是在合理的协议非常有限的以前的工作。我们观察到大的HCl排放因子范围为2-10 g/kg。考虑到全球废物流中的氯含量，垃圾燃烧可能产生多达6-9 Tg/年的HCl，这将使其成为该化合物的主要来源。在干燥环境中焚烧垃圾产生的HCl可能比在潮湿地区产生的HCl对大气的影响相对更大。垃圾燃烧PM2.5中含有左旋葡聚糖和K，其浓度与生物质燃烧相似，因此在某些地区使用这些示踪剂估计BB时可能会产生干扰。在本研究中，半乳糖是与BB最密切相关的脱水糖。细颗粒锑（Sb）显示出作为垃圾燃烧示踪剂的初步前景，并表明这种来源可能会在墨西哥城大都市区贡献大量的PM2.5。由于工业生物燃料的使用而造成的燃料消耗和排放很难在区域一级加以描述。部分原因是使用的燃料种类繁多，典型的微型企业利润率很低。制砖窑产生的EFPM2.5总量较低（与1.6克/千克相似），但EC/OC比率非常高（6.72）。以前关于砖窑的文献很少，但确实记录了一些严重的地方影响。结合来自墨西哥、巴西和赞比亚的数据，我们发现木炭制造窑在大约一周的使用寿命内，VOC/CO会增加8倍。墨西哥炭窑的乙酸排放系数比其他地方高得多。我们的木炭窑EFPM2.5排放系数为1.1 g/kg，低于之前针对所有类型窑炉的建议值。我们推测，一些PM2.5是在泥土窑的墙壁清除。
In central Mexico during the spring of 2007 we measured the initial emissions of 12 gases and the aerosol speciation for elemental and organic carbon (EC, OC), anhydrosugars, Cl-, NO3-, and 20 metals from 10 cooking fires, four garbage fires, three brick making kilns, three charcoal making kilns, and two crop residue fires. Global biofuel use has been estimated at over 2600 Tg/y. With several simple case studies we show that cooking fires can be a major, or the major, source of several gases and fine particles in developing countries. Insulated cook stoves with chimneys were earlier shown to reduce indoor air pollution and the fuel use per cooking task. We confirm that they also reduce the emissions of VOC pollutants per mass of fuel burned by about half. We did not detect HCN emissions from cooking fires in Mexico or Africa. Thus, if regional source attribution is based on HCN emissions typical for other types of biomass burning (BB), then biofuel use and total BB will be underestimated in much of the developing world. This is also significant because cooking fires are not detected from space. We estimate that similar to 2000 Tg/y of garbage are generated globally and about half may be burned, making this a commonly overlooked major global source of emissions. We estimate a fine particle emission factor (EFPM2.5) for garbage burning of similar to 10.5 +/- 8.8 g/kg, which is in reasonable agreement with very limited previous work. We observe large HCl emission factors in the range 2-10 g/kg. Consideration of the Cl content of the global waste stream suggests that garbage burning may generate as much as 6-9 Tg/yr of HCl, which would make it a major source of this compound. HCl generated by garbage burning in dry environments may have a relatively greater atmospheric impact than HCl generated in humid areas. Garbage burning PM2.5 was found to contain levoglucosan and K in concentrations similar to those for biomass burning, so it could be a source of interference in some areas when using these tracers to estimate BB. Galactosan was the anhydrosugar most closely correlated with BB in this study. Fine particle antimony (Sb) shows initial promise as a garbage burning tracer and suggests that this source could contribute a significant amount of the PM2.5 in the Mexico City metropolitan area. The fuel consumption and emissions due to industrial biofuel use are difficult to characterize regionally. This is partly because of the diverse range of fuels used and the very small profit margins of typical micro-enterprises. Brick making kilns produced low total EFPM2.5 (similar to 1.6 g/kg), but very high EC/OC ratios (6.72). Previous literature on brick kilns is scarce but does document some severe local impacts. Coupling data from Mexico, Brazil, and Zambia, we find that charcoal making kilns can exhibit an 8-fold increase in VOC/CO over their approximately one-week lifetime. Acetic acid emission factors for charcoal kilns were much higher in Mexico than elsewhere. Our dirt charcoal kiln EFPM2.5 emission factor was similar to 1.1 g/kg, which is lower than previous recommendations intended for all types of kilns. We speculate that some PM2.5 is scavenged in the walls of dirt kilns.