Quantifying the deposition of particulate matter on climber vegetation on living walls

The beneficial effect of vegetation on particle deposition is often stated in arboricultural literature but has rarely been researched in detail. To quantify these filtering effects of façade greening, it is necessary to study the accumulation properties of leaf surfaces on particle adsorption. In this paper attention will be given to a measure technique for particle adsorption on vegetation. The presented preliminary study aims to classify the total amount of particles by counting of particles on ESEM photographs. In the PhD research more attention will be given on the relation between particle reduction and the effect of vegetation on air quality improvements. Two locations were investigated, namely: leaves from near a traffic road and from a woodland. A difference in the particle amount was found at the underside and upper side of the leaves. For example, in a sampling at early autumn for the road location roughly 7000 particles (per 1275 × 950 μm) were counted for the upper side, and, roughly 3200 particles for the underside. Also a difference in particle amount was found between the two different locations, respectively roughly 7000 particles for the upper side of the leaf at the road location and roughly 3300 for the woodland location. The comparison must give more insight into the sink capacity of vegetation, but also between the environments. In the paper, results of counting particles on leaves from both locations are provided via a factorial design approach with four independent factors at two levels (height, leaf, time and environment). The outcome of the factorial design shows that there is a difference between the collecting capacity of the leaf (upper side/underside) and between the environments (road/woodland). Fine and ultra-fine particles (i.e., the fractions that are potentially the most harmful to human health) were more abundantly found on the leaves than coarser particles. Also some energy dispersive X-ray analysis (EDS) of the adhered particles is provided. As the main conclusion of this research, it can be said that counting particles instead of weighing particles on a specific leaf area seems to be a proper way to classify aerosol deposition on vegetation.