摘要:
室内薪柴燃烧是大气污染的重要来源,其排放的污染物对气候变化和人体健康都有很大影响。对该来源排放量的可靠估算是进行排放效应分析和合理控制的重要前提,而估算的可靠性主要取决于燃料消耗量和排放因子的准确性。目前,我国针对农村柴灶薪柴燃烧颗粒物排放因子的测定数据很少,变异很大,不足以支持可靠的排放清单估算。测定了9种薪柴(枫桦、兰考泡桐、黑杨、大叶风杨、楝树、枣树、柿树、桑树和桃树)在中国北方典型农村炉灶中燃烧产生的颗粒物(PM)、有机碳(OC)和元素碳(EC)的排放因子。受燃料种类、性质和燃烧条件的影响,测得的排放因子差别较大。9种薪柴各自的PM、EC和OC的排放因子变化范围分别为(0.74 ±0.13)~(6.23 ±1.47) g·kg-1,(0.10 ±0.06)~(0.97 ±0.28) g·kg-1和(0.14 ±0.03)~(3.81 ±0.92) g·kg-1(以干质量计)。全部薪柴的PM、EC和OC的排放因子均值和标准差分别为(2.58 ±2.15)、(0.29 ±0.31)和(0.98 ±1.24) g·kg-1。室内薪柴燃烧PM、EC和OC排放因子之间呈显著的相关性关系。各种薪柴燃烧排放的颗粒物粒径分布相似,均以细颗粒物为主,PM2.1占PM10总质量的90%以上。此外,除EC排放因子外,薪柴燃烧的PM和OC排放因子与校正燃烧效率显著负相关(P < 0.05)。细颗粒物组分PM2.1与校正燃烧效率显著负相关(P < 0.05),与燃料含水量显著正相关(P < 0.05)。
Abstract:
Emissions of air pollutants from residential wood combustion affect climate forcing and human health significantly. A reliable estimation of emission from the source which depends on fuel consumption and emission factors (EFs) is the important prerequisite for emission impact assessment and control strategy. Unfortunately, EFs of particulate matter (PM) for rural residential firewood combustion published are limited for developing countries including China and the data reported often vary significantly, resulting in high uncertainties in emission inventory. Therefore, the first-hand EFs from field measurements of household wood combustion are badly needed in China nowadays. In this study, 9 wood fuels (ribbed birch, Paulownia elongate, black poplar, China aspen, Chinaberry, jujube, persimmon, mulberry and peach) were burned in a typical residential stove used in rural areas of North China to measure EFs of PM, organic carbon (OC), and elemental carbon (EC). Results showed that the measured EFs varied significantly among wood types and were affected by fuel properties and combustion conditions. EFs of PM, OC, and EC (EFPM, EFOC, and EFEC, respectively) of nine wood types were in the range of 0.74 ±0.13-6.23 ±1.47, 0.10 ±0.06-0.97 ±0.28, and 0.14 ±0.03-3.81 ±0.92 g·kg-1 (dry basis), respectively. On average of all wood types, EFPM, EFOC, and EFEC were 2.58 ±2.15, 0.29 ±0.31, and 0.98 1.24 g·kg-1, respectively. Significant correlations among EFPM, EFOC, and EFEC were expected. Similarity in size distribution was found in PM emitted from various tested wood. It was demonstrated that fine PM dominated the total PM from wood combustion, and more than 90% of the total PM were less than 2.1 μm in diameter (PM2.1). Modified combustion efficiency (MCE) was found to be negatively correlated with EFs of PM and OC(P <0.05). When it came to size distribution of PM, MCE and wood moisture were found to be negatively and positively correlated with PM2.1, respectively(P < 0.05).
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