Transmission of infectious respiratory diseases starts from pathogen-laden respiratory droplets released during coughing, sneezing, or speaking. Here we report an on-mask chemical modulation strategy, whereby droplets escaping a masking layer are chemically contaminated with antipathogen molecules (e.g., mineral acids or copper salts) preloaded on polyaniline-coated fabrics. A colorimetric method based on the color change of polyaniline and a fluorometric method utilizing fluorescence quenching microscopy are developed for visualizing the degree of modification of the escaped droplets by H⁺ and Cu²⁺, respectively. It is found that even fabrics with low fiber-packing densities (e.g., 19%) can readily modify 49% of the escaped droplets by number, which accounts for about 82% by volume. The chemical modulation strategy could offer additional public health benefits to the use of face covering to make the sources less infectious, helping to strengthen the response to the current pandemic or future outbreaks of infectious respiratory diseases.

传染性呼吸道疾病的传播始于咳嗽、打喷嚏或说话时释放的携带病原体的呼吸道飞沫。在这里，我们报告了一种掩模上的化学调制策略，即逃离掩模层的液滴被预装在聚苯胺涂层织物上的抗病原体分子（例如无机酸或铜盐）化学污染。开发了基于聚苯胺颜色变化的比色法和利用荧光猝灭显微镜的荧光法，分别用于可视化逃逸液滴被H ⁺和Cu ²⁺修饰的程度。研究发现，即使是纤维堆积密度较低（例如19%）的织物也能轻易地改变49%的逃逸液滴（按数量计算），约占体积的82%。化学调制策略可以为使用面罩降低传染源的传染性提供额外的公共卫生益处，有助于加强对当前大流行或未来传染性呼吸道疾病爆发的应对。