Urban particulate pollution reduction by four species of green roof vegetation in a UK city

Potential of Particle Matter Dry Deposition on Green Roofs and Living Walls Vegetation for Mitigating Urban Atmospheric Pollution in Semiarid Climates

“…Values of this study and our study are not directly comparable because testing conditions and measurement technologies are different. For example, Speak et al [12] exposed GR vegetation to outdoor conditions in a roof of the city of Manchester (UK), while our study correspond to higher indoor concentrations under very well controlled experimental conditions. On the other hand, Speak et al [12] estimated the capture of PM using a scanning electron microscopy, whereas our research used the gravimetric method.…”

“…The dry deposition values of PM 10 are higher than those found in the literature for the same or similar species. For example, Speak et al [12] reported values of 0.88 and 0.12 µg·cm −2 ·day −1 for F. rubra and S. album, respectively. Values of this study and our study are not directly comparable because testing conditions and measurement technologies are different.…”

“…In addition, it is difficult to compare the results shown in Table 1 as they report dry deposition of PM during Sustainability 2018, 10, 2431 3 of 18 different measurement periods in urban areas with different ambient PM concentrations. For example, the measuring period in Speak et al [12] was two years while it was just one month in Chen et al [8]. Nonetheless, the differences in the results reported in Table 1 suggests that some species are more efficient in mitigating PM pollution.…”

“…First, two main approaches to evaluate that effect are reported in the literature: (1) measuring the dry deposition of PM on GRs and LWs vegetation and (2) estimating the reduction of PM concentration due to GRs and LWs vegetation. While dry deposition is mainly measured by the gravimetric method [8,[10][11][12], the impact of GRs and LWs on PM concentration is mostly measured in environmental chambers [13,14]. An exception is the study of Tan and Sia [15], who measured the impact of GRs on outdoor PM concentration.…”

“…Nonetheless, the differences in the results reported in Table 1 suggests that some species are more efficient in mitigating PM pollution. Speak et al [12] explained those differences by the variability in the species' morphology. Chen et al [8] pointed out that the difference among the effectiveness as bio-filter of PM of each species could be associated with the layout configuration (relative location among species) in the environment where they develop.…”