Ecology & Safety, Volume 15, 2021

Abstract: Urban vegetation is widely recognized for its capability to remove / reduce the pollutants in atmospheric air, either by deposition or by stomatal uptake. The main aim of the study was to identify certain species in Romanian flora enable to reduce the concentration of certain gaseous pollutants, and to test their bio-filtration/bioremediation potential related to the underground spaces with auto traffic. Thus, two plant species were tested for their potential in removing a model pollutant (e.g. toluene traces, as a common traffic exhaust pollutant) from the atmospheric air: Hedera helix (Araliaceae) and Chrysopogon gryllus (Poaceae). The selection process of plant species took into consideration the following criteria: well developed foliage, long vegetation period, resistance to hydric stress, shadow tolerance, and aesthetic aspect. The experiments were performed using a small-size airtight greenhouse as an air biofiltration system, having inserted 12 identical pots with selected species (6 with Hedera and 6 with Chrysopogon) and supplied with the model pollutant. A similar set-up in the absence of the model pollutant was considered for comparison purposes. Daily analysis of small air samples from the above mentioned system shows a decrease in pollutant concentration over the course of the test period, without any significant change in plant morphology. The preliminary results highlights the high potential of the investigated (combined) species in improving air quality in the underground spaces with auto traffic, by reducing a model contaminant concentration under experimental conditions. Still, further investigation is needed in order to quantify the individual plant performance towards this pollutant removal as well as their performance under extended gas mixture and the effect of other environmental variables on the efficiency of this process.