Soil drought increases atmospheric fine particle capture efficiency of Norway spruce

Abstract

Atmospheric fine particles from natural and anthropogenic sources reduce air quality and thus cause undesirable health and climate effects. Trees can act as obstacles to dispersal of particle pollution and thus remove a significant amount of particulate matter from the atmosphere. However, the significance of environmental factors in this context is not well understood. The effect of drought on fine particle capture efficiency (Cp) of Norway spruce (Picea abies) saplings was studied in controlled wind-tunnel experiments. The results showed that Cp of Norway spruce saplings with low soil water availability was 0.065% and well watered saplings 0.051%. Particle deposition onto all parts of the canopy was equally efficient with no difference in Cp between current- and previous-year needle generations. The results suggest that water availability significantly affects Cp of Norway spruce, which may be partly due to altered stomatal function.