Missouri University of Science & Technology, Rolla, MO, USA.
Indoor Air. 2011 Aug;21(4):319-27. doi: 10.1111/j.1600-0668.2010.00707.x. Epub 2011 Feb 7.
Reaction rates and reaction probabilities have been quantified on model indoor surfaces for the reaction of ozone with two monoterpenes (Δ(3) -carene and d-limonene). Molar surface loadings were obtained by performing breakthrough experiments in a plug-flow reactor (PFR) packed with beads of glass, polyvinylchloride or zirconium silicate. Reaction rates and probabilities were determined by equilibrating the PFR with both the terpene and the ozone and measuring the ozone consumption rate. To mimic typical indoor conditions, temperatures of 20, 25, and 30°C were used in both types of experiments along with a relative humidity ranging from 10% to 80%. The molar surface loading decreased with increased relative humidity, especially on glass, suggesting that water competed with the terpenes for adsorption sites. The ozone reactivity experiments indicate that higher surface loadings correspond with higher ozone uptake. The reaction probability for Δ(3) -carene with ozone ranged from 2.9 × 10(-6) to 3.0 × 10(-5) while reaction probabilities for d-limonene ranged from 2.8 × 10(-5) to 3.0 × 10(-4) . These surface reaction probabilities are roughly 10-100 times greater than the corresponding gas-phase values. Extrapolation of these results to typical indoor conditions suggests that surface conversion rates may be substantial relative to gas-phase rates, especially for lower volatility terpenoids.
At present, it is unclear how important heterogeneous reactions will be in influencing indoor concentrations of terpenes, ozone and their reaction products. We observe that surface reaction probabilities were 10 to 100 times greater than their corresponding gas-phase values. Thus indoor surfaces do enhance effective reaction rates and adsorption of terpenes will increase ozone flux to otherwise low-reactivity surfaces. Extrapolation of these results to typical indoor conditions suggests that surface conversion rates may be substantial relative to gas-phase rates, especially for lower volatility terpenoids.
在填充有玻璃珠、聚氯乙烯珠或硅酸锆珠的活塞流反应器（PFR）中进行突破实验，获得了臭氧与两种单萜（Δ(3) -蒈烯和柠檬烯）在模型室内表面上的反应速率和反应概率的摩尔表面负载量。通过使 PFR 与萜烯和臭氧达到平衡并测量臭氧消耗速率来确定反应速率和概率。为了模拟典型的室内条件，在两种类型的实验中使用 20、25 和 30°C 的温度以及 10%至 80%的相对湿度。摩尔表面负载量随着相对湿度的增加而降低，尤其是在玻璃上，这表明水与萜烯竞争吸附位。臭氧反应性实验表明，较高的表面负载量对应于较高的臭氧吸收量。臭氧与Δ(3) -蒈烯的反应概率范围为 2.9×10(-6)至 3.0×10(-5)，而臭氧与柠檬烯的反应概率范围为 2.8×10(-5)至 3.0×10(-4)。这些表面反应概率大约是相应气相值的 10-100 倍。将这些结果外推到典型的室内条件表明，表面转化速率相对于气相速率可能相当大，特别是对于挥发性较低的萜类化合物。
目前，异相反应对影响室内萜类化合物、臭氧及其反应产物浓度的重要性尚不清楚。我们观察到表面反应概率是其相应气相值的 10 到 100 倍。因此，室内表面确实会提高萜烯的有效反应速率和吸附，从而增加臭氧通量到 otherwise 低反应性表面。将这些结果外推到典型的室内条件表明，表面转化速率相对于气相速率可能相当大，特别是对于挥发性较低的萜类化合物。
