Institute for Atmospheric and Environmental Research, Bergische Universität Wuppertal, Wuppertal, Germany.
Indoor Air. 2021 Jan;31(1):116-127. doi: 10.1111/ina.12714. Epub 2020 Aug 1.
In the present study, emission indices for NO, NO , HONO, HCHO, CO, particle mass, and particle numbers including particle size distributions for three different offering candles were determined. The candles investigated showed similar emission characteristics with emission indices (g/kg) in good agreement with former candle emission studies. An average HONO/NO emission ratio of 6.6 ± 1.1% was obtained, which is much higher compared to most other combustion sources, indicating that candles may be a significant indoor source of this important trace gas. The particle size distributions indicate that the majority of the emitted particles are in the size range 7 - 15 nm. Three modes were observed during burning the candles with very different emission profiles: a "normal burning" mode characterized by low particle number emission rates and small particles; an initial "sooting" behavior after ignition, and a final "smoldering" phase upon candle extinction with higher particle number emission rates and larger particles. The particle emission upon extinction is dependent on the extinction method. The NO emission indices were applied in a simple box model to calculate typical indoor NO concentration levels from candle emissions, which were in excellent agreement with direct measurements in a typical indoor environment.
在本研究中，测定了三种不同蜡烛的 NO、NO 、HONO、HCHO、CO、颗粒质量和颗粒数排放指数，包括颗粒尺寸分布。研究发现，这些蜡烛具有相似的排放特征，其排放指数（g/kg）与之前的蜡烛排放研究非常吻合。得到的 HONO/NO 排放比平均为 6.6±1.1%，与大多数其他燃烧源相比要高得多，这表明蜡烛可能是这种重要痕量气体的一个重要室内源。颗粒尺寸分布表明，大部分排放的颗粒处于 7-15nm 的尺寸范围内。在燃烧蜡烛时观察到三种模式，它们具有非常不同的排放特征：一种是“正常燃烧”模式，其特征是颗粒数排放率低且颗粒小；一种是点火后的初始“冒烟”行为；以及蜡烛熄灭时的最终“闷烧”阶段，其颗粒数排放率高且颗粒大。熄灭时的颗粒排放取决于熄灭方法。将 NO 排放指数应用于一个简单的箱式模型中，计算了蜡烛排放引起的典型室内 NO 浓度水平，该水平与典型室内环境中的直接测量结果非常吻合。
