Department of Civil, Architectural and Environmental Engineering, Drexel University , 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States.
Environ Sci Technol. 2014 Jul 15;48(14):7899-908. doi: 10.1021/es5009906. Epub 2014 Jun 30.
Secondary organic aerosol (SOA) results from the oxidation of reactive organic gases (ROGs) and is an indoor particle source. The aerosol mass fraction (AMF), a.k.a. SOA yield, quantifies the SOA forming potential of ROGs and is the ratio of generated SOA to oxidized ROG. The AMF depends on the organic aerosol concentration, as well as the prevalence of later generation reactions. AMFs have been measured in unventilated chambers or steady-state flow through chambers. However, indoor settings have outdoor air exchange, and indoor SOA formation often occurs when ROGs are transiently emitted, for instance from emissions of cleaning products. Herein, we quantify "transient AMFs" from ozonolysis of pulse-emitted limonene in a ventilated chamber, for 18 experiments at low (0.28 h(-1)), moderate (0.53 h(-1)), and high (0.96 h(-1)) air exchange rates (AER) with varying initial ozone-limonene ratios. Transient AMFs increased with the amount of ROG reacted; AMFs also increased with decreasing AERs and increasing initial ozone-limonene ratios, which together likely promoted more ozone reactions with the remaining exocyclic bond of oxidized limonene products in the SOA phase. Knowing the AER and initial ozone-limonene ratio is crucial to predict indoor transient SOA behavior accurately.
二次有机气溶胶 (SOA) 是由反应性有机气体 (ROG) 氧化形成的，也是室内颗粒的一个来源。气溶胶质量分数 (AMF)，又名 SOA 产率，量化了 ROG 的 SOA 形成潜力，是生成的 SOA 与氧化的 ROG 的比值。AMF 取决于有机气溶胶浓度以及后续生成反应的普遍性。AMF 已经在不通风的腔室或稳态流动通过腔室中进行了测量。然而，室内环境存在室外空气交换，当 ROG 瞬态排放时，例如从清洁产品的排放中，室内 SOA 就会形成。在此，我们在通风腔室中量化了脉冲排放的柠檬烯的臭氧氧化产生的“瞬态 AMF”，共进行了 18 次实验，空气交换率 (AER) 分别为低 (0.28 h(-1))、中 (0.53 h(-1)) 和高 (0.96 h(-1))，臭氧-柠檬烯初始比也有所不同。瞬态 AMF 随 ROG 反应量的增加而增加；AMF 也随 AER 的降低和初始臭氧-柠檬烯比的增加而增加，这可能共同促进了剩余的具有外环键的氧化柠檬烯产物在 SOA 相中与臭氧发生更多的反应。了解 AER 和初始臭氧-柠檬烯比对于准确预测室内瞬态 SOA 行为至关重要。
