The impact of climate factors on airborne particulate matter removal by plants

Abstract

Airborne particulate matter (PM) filtration by plants is a process of continuous PM accumulation and periodic washing, in which climate factors plays a key role. However, most of the relevant studies have focused on the impact of single meteorological factors, the influencing mechanism of comprehensive meteorological factors, i.e., climate, on PM filtration by plants remains unclear. Coupled with the i-Tree model, we established a multi-cycle PM removal (PMR) model with the focus on the impact of wind and precipitations on the PM filtration function of plants, so as to inform the suitability of different climates for green space creation. Interactions between relevant parameters were analyzed through simulation. It was found that the PM capture threshold of plants and the time required to reach this threshold both decreased with wind speed (V). The PMR performance of plants increased and then decreased with V, and the optimal V decreased with increasing precipitation interval (T). The performance of different climates in PMR could be ranked as: short T & high V > short T & low V > long T & low V > long T & high V. Within areas characterized by a long T, it is suitable to create green spaces in the places where V is relatively low and with the pattern of large patches and high-density to reduce plants’ exposure V. Additionally, the relative magnitudes of the PMR of different plant species may change with V or T; species selection should match the regional climate. This study can help to clarify the influencing mechanism of climate factors on the PMR performance of plants and provides guidance for creating green spaces for PM control under different climate regimes.