Single-Rain Droplet Amperometry Reveals Spontaneous and Regulated H 2 O 2 Formation on Leaf Surfaces

sensing but on revealing natural phenomena and their regulating factors on leaves, as probed by miniaturized sensors and optical kits. These findings reveal previously hidden interfacial chemistry, demonstrating that tiny rain droplets can act not only as cleansing agents but also as natural oxidants, potentially providing protection against microbial contamination and localized biocorrosion, although further studies on natural rain droplets are needed. The results further suggest that similar processes may occur in aerosols, dew, and fog, highlighting the need for further investigation of spontaneous reactive oxygen species formation in natural droplets.