Porous Lignin Nanospheres as Microscopic Air Purifiers for Antioxidant‐Configurable Cigarette Filters

Abstract Trees, consisting of leaves, trunks, etc., efficiently eliminate gaseous pollutants and serve as an indispensable air purification system for Earth. In this study, lignin from trunks and phytol from leaves are co‐assembled into macroporous nanospheres with high purification efficiency for scavenging gaseous reactive oxygen species (ROS) and harmful gases, which are integrated into cigarette filters for lung protection. The alkyl chains of phytol disrupt the π–π stacking in lignin, forming pore throats that expand from 0 to 120 nm as phytol content increases. Consequently, the higher levels of anchored phytol, the greater the antioxidant capacity of the co‐assemblies. The macroporous nanospheres are subsequently loaded into cigarette filters, with each gram of porous nano‐lignin capable of treating ≈100 standard cigarettes. The gaseous ROS scavenging efficiency can reach up to 97%, effectively removing harmful gases like carbon monoxide and formaldehyde, outperforming existing cigarette filters. In a mouse model, cigarette filters containing these microscopic air purifiers significantly suppressed inflammation and provided notable lung tissue protection. This study presents a robust non‐covalent method that is both straightforward and efficient, enabling the rapid application of plant extracts in highly effective and sustainable filter materials.