Highlights
- Different Australian vegetation representatives were successfully trialled to serve as green barriers.
- The efficiency of removal of course particle (>1 μm) could exceed 90% for selected plants.
- Fine particles (>0.5 μm) are not very effectively removed requiring some alternative mechanisms for purification.
Abstract
Urban air quality monitoring and control are becoming increasingly important as the amount of airborne pollutants is directly related to public health. One of the main strategies to improve air quality is to increase the number of plants per unit land surface area across cities through urban greening. In addition to the process of photosynthesis, which minimizes the content of harmful gas impurities into the atmosphere, the planting of relevant vegetation in the form of high-density street vegetation, green walls or green façades, acts as a barrier to the passage of atmospheric aerosol particles into crowded areas. Depending on the availability of local plants, various design strategies could be used to minimise air pollution and achieve maximum air quality. On this basis, it is important to investigate filtration capabilities of a range of locally available plants enabling landscape architects to design the most cost-effective green barriers in various countries. Four common representatives of Australian flora have been selected and tested in this study as promising candidates. A number of configuration scenarios involving manipulation of a layer thickness and biomass packing were tested as potential filters for collection of aerosols sizing from 0.5 μm diameter. The results showed that the plant materials were highly efficient in filtering coarse particles (≥2.5 μm), with efficiencies ranging from 50.1% to 99.9%. The smaller particle sizes were filtered with comparatively lower efficiencies, ranging from 0.6% to 51.3% and 8.6%–79.1% for particles of 0.5 μm and 1 μm diameter respectively. Optimal scenarios were proposed and discussed.
