Abstract:
Ozone and its oxidation products result in negative health effects when inhaled. Despite painted surfaces being the most abundant surface in indoor spaces, surface loss remains one of the largest uncertainties in the indoor ozone budget. Here, ozone uptake coefficients (γO3) on painted surfaces were measured in a flow-through reactor where 79% of the inner surfaces were removable painted glass sheets. Flat white paint initially had a high uptake coefficient (8.3 × 10-6) at 20% RH which plateaued to 1.1 × 10-6 as the paint aged in an indoor office over weeks. Increasing the RH from 0 to 75% increased γO3 by a factor of 3.0, and exposure to 134 ppb of α-terpineol for 1 h increased γO3 by a factor of 1.6 at 20% RH. RH also increases α-terpineol partitioning to paint, further increasing ozone loss, but the type of paint (flat, eggshell, satin, semigloss) had no significant effect. A kinetic multilayer model captures the dependence of γO3 on RH and the presence of α-terpineol, indicating the reacto-diffusive depth for O3 is 1 to 2 μm. Given the similarity of the kinetics on aged surfaces across many paint types and the sustained reactivity during aging, these results suggest a mechanism for catalytic loss.
摘要:
臭氧及其氧化产物在吸入时会对健康产生负面影响。尽管油漆表面是室内空间中最丰富的表面,表面损失仍然是室内臭氧预算中最大的不确定性之一。这里,在流通式反应器中测量涂漆表面上的臭氧吸收系数(γO3),其中79%的内表面是可移动的涂漆玻璃板。平白油漆最初在20%RH下具有较高的吸收系数(8.3×10-6),随着油漆在室内办公室中老化数周,其稳定至1.1×10-6。将RH从0增加到75%,使γO3增加了3.0倍,而在20%RH下,暴露于134ppb的α-松油醇1小时,使γO3增加了1.6倍。RH还增加了α-松油醇与油漆的分配,进一步增加臭氧损失,但是油漆的类型(扁平,蛋壳,缎面,半丢失)没有显著影响。动力学多层模型捕获了γO3对RH和α-松油醇的存在的依赖性,表明O3的反应扩散深度为1至2μm。考虑到许多油漆类型的老化表面的动力学相似性以及老化过程中的持续反应性,这些结果表明了催化损失的机制。