Deposition of traffic-related air pollutants on leaves of six evergreen shrub species during a Mediterranean summer season

Six evergreen broad-leaved shrub species (Viburnum tinus subsp. lucidum L., Arbutus unedo L., Pho-tinia × fraseri Dress., Laurus nobilis L., Elaeagnus × ebbingei L., Ligustrum japonicum Thunb.) were tested fortheir capacity to accumulate pollutants on the surface of their current season leaves in a Mediterraneanenvironment. Plants were planted along a road in 2010 and exposed to traffic pollution. Leaf elementdeposition (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn) was analyzed sixtimes from early summer to early autumn 2012. Particulate matter on leaves, element concentration ofparticulate matter in the air and meteorological parameters were measured. Elements on leaves wererelated to meteorological conditions to study the inter-relations. E. × ebbingei, P. × fraseri and V. lucidumwere found to accumulate more pollutants, while L. nobilis and A. unedo were the lowest accumulators.A common trend of element depositions was found. Generally, elements increased from the first to thesecond sampling (28 June to 19 July) and, thereafter, decreased until the early autumn. Element depo-sitions depended on species and meteorological parameters. Rain decreased the element accumulationon leaves, whilst an increase in wind velocity and element concentrations (in the air) tended to increasethe presence of elements on leaves. Meteorological conditions were confirmed to be important factorsmodifying the dynamics of pollution deposition and their removal from leaves during a season.