烹饪有机气溶胶(COA)的暴露与人们的日常生活密切相关。尽管对COA的模型化合物如油酸进行了广泛的研究,真实COA的异质臭氧分解的复杂性以及湿度等环境条件的影响仍然难以捉摸。在这项工作中,使用漫反射红外傅里叶变换(DRIFTS)光谱研究了加热花生油排放物中COA代理的臭氧分解,和质子转移反应飞行时间质谱仪(PTR-ToF-MS)。我们发现,由于水和臭氧在COA上的竞争性吸附,湿度阻碍了臭氧与CC双键之间的反应。尽管在没有湿度的情况下,可见光对COA的臭氧分解几乎没有影响,在湿气存在下,可见光显着促进臭氧分解CO的产生。它可能归因于水衍生的活性氧(ROS,主要是HO•)来自COA中多环芳烃(PAHs)的光敏作用。我们还发现,湿度可以增强COA中羧酸二聚体的解聚和固有缩醛的水解。此外,在COA的深色和浅色臭氧分解过程中,湿度都会促进VOC的释放。这项工作揭示了湿度响应和光响应成分在COA臭氧分解过程中的重要作用,VOC释放的变化可以指导人体在室内空气中VOC暴露的控制。
The exposure to cooking organic aerosols (COA) is closely related to people\'s daily lives. Despite extensive investigations into COA\'s model compounds like oleic acid, the intricacies of heterogeneous
ozonolysis of real COA and the effects of ambient conditions like humidity remain elusive. In this work, the
ozonolysis of COA proxies from heated peanut oil emissions was investigated using diffuse reflectance infrared Fourier transform (DRIFTS) spectroscopy, and proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). We found that humidity hinders the reaction between ozone and CC double bonds due to the competitive adsorption of water and ozone on COA. Although visible light has little influence on the
ozonolysis of COA in the absence of humidity, the ozonolytic CO production is significantly promoted by visible light in the presence of humidity. It may be attributed to the formation of water-derived reactive oxygen species (ROS, mainly HO•) from the photosensitization of polycyclic aromatic hydrocarbons (PAHs) in COA. We also found that humidity can enhance the depolymerization of carboxylic acid dimers and hydrolysis of intrinsic acetals in the COA. Moreover, humidity promotes the release of VOCs during both the dark and light
ozonolysis of COA. This work reveals the important roles of humidity-responsive and photo-responsive components in COA during its
ozonolysis, and the change in VOC release may guide the control of human VOC exposure in indoor air.