Utilization of Mosses in Green Infrastructure for Mitigating Particulate Matter Air Pollution

Green infrastructure (GI) uses different plants to deliver various ecosystem services in urban environments. Among these services, pollution control is critical due to its association with disease spread. According to The World Health Organisation (WHO), Particulate Matter (PM) is a major threat to human health from air pollution. The most effective GI mitigation application is a vertical barrier positioned between the pollution sources and receptors. Selecting suitable plants for such barriers is essential, taking into account that most of the PM occurs during winter from wood-burning heating systems.

Bryophytes, or mosses, are evergreen plants and have a high capacity for air pollution absorption due to their morphology. To identify the most effective moss species for PM absorption, a laboratory experiment was conducted at the Laboratory of the Physics and Chemistry of Environment and Space in Orleans (LPC2E-CNRS), France under the supervision of Dr. Jean-Baptsite Renard. A custom-engineered air pollution chamber was built with a vertical GI barrier inside to measure PM absorption before and after the barrier. Pollutant transport was simulated by the traction of an installed fan within the chamber. Results from the Pollutrack sensors revealed an average PM absorption efficiency of 40% for PM2.5 and 46% for PM10 based on 26 experiments using moss species Dicranum scoparium, Plagiomnium affine, and Hypnum cupressiforme. These results represent the optimal absorption capacity of mosses under controlled laboratory conditions, accounting for limitations such as humidity, air pressure, and temperature in the laboratory. This research demonstrates that mosses are a highly effective choice for the GI with a significant PM absorption potential. Further studies in real urban environments are recommended to validate these findings.