Photocatalytic cement is self-cleaning due to the addition of titanium dioxide (TiO₂) nanoparticles, which react with sunlight (UV) and produce reactive oxygen species (ROS). Construction workers using photocatalytic cement are exposed not only to cement particles that are irritants but also to nano TiO₂ and UV, both carcinogens, as well as the generated ROS. Quantifying ROS generated from added nano TiO₂ in photocatalytic cement is necessary to efficiently assess combined health risks. We designed and built an experimental setup to generate, under controlled environmental conditions (i.e., temperature, relative humidity, UV irradiance), both regular and photocatalytic cement aerosols. In addition, cement working activities—namely bag emptying and concrete cutting—were simulated in an exposure chamber while continuously measuring particle size distribution/concentration with a scanning mobility particle sizer (SMPS). ROS production was measured with a newly developed photonic sensing system based on a colorimetric assay. ROS production generated from the photocatalytic cement aerosol exposed to UV (3.3∙10⁻⁹ nmol/pt) was significantly higher than for regular cement aerosol, either UV-exposed (0.5∙10⁻⁹ nmol/pt) or not (1.1∙10⁻⁹ nmol/pt). Quantitatively, the level of photocatalytic activity measured for nano TiO₂-containing cement aerosol was in good agreement with the one obtained with only nano TiO₂ aerosol at similar experimental conditions of temperature and relative humidity (around 60%). As a consequence, we recommend that exposure reduction strategies, in addition to cement particle exposures, also consider nano TiO₂ and in situ–generated ROS, in particular if the work is done in sunny environments.

Graphical abstract

由于添加了与太阳光（UV）反应并产生活性氧（ROS）的二氧化钛（TiO ₂）纳米颗粒，因此光催化水泥具有自清洁功能。使用光催化水泥的建筑工人不仅会暴露于刺激性的水泥颗粒中，而且会暴露于纳米TiO ₂和紫外线，致癌物以及所产生的活性氧。定量从添加的纳米TiO _2中产生的ROS光催化水泥中的维生素B是有效评估综合健康风险所必需的。我们设计并建立了一个实验装置，可以在受控的环境条件下（即温度，相对湿度，紫外线辐射）产生常规和光催化水泥气溶胶。此外，在暴露室中模拟了水泥工作活动（即排空袋子和切割混凝土），同时使用扫描移动粒度仪（SMPS）连续测量粒度分布/浓度。ROS的产生是使用新开发的基于比色测定的光子传感系统进行测量的。暴露在紫外线下的光催化水泥气溶胶产生的ROS产生（3.3∙10 ^-9  nmol / pt）显着高于常规水泥气溶胶，无论是紫外线暴露（0.5∙10^-9  nmol / pt）（1.1∙10 ^-9  nmol / pt）。定量地，在相似的温度和相对湿度（约60％）实验条件下，含纳米TiO ₂的水泥气溶胶的光催化活性水平与仅由纳米TiO _2的气溶胶获得的光催化活性水平良好。因此，我们建议除水泥颗粒暴露外，减少暴露的策略还应考虑纳米TiO ₂和原位生成的ROS，尤其是在阳光明媚的环境下进行时。

图形概要