Since conventional air pollution monitoring stations provide coarse-scale information on exposure to pollutants, only , a growing interest in monitoring and modeling urban air pollution to obtain information with a higher spatial resolution is apparent. One of the possibilities of street-scale monitoring is biomonitoring of urban vegetation. With increasing traffic intensity, leaves act as a natural sink for particulate matter (PM) (Kardel et al., 2011; Maher et al., 2008), and can even enrich in nitrogen (Laffray et al., 2010) or heavy metals, such as lead (Gajic et al., 2009). Besides deposition, retention and even enrichment of trace elements and metals, leaves are exposed to a whole range of traffic-induced gaseous pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2) which have an impact on their physiological behavior.
Biomonitoring of natural vegetation allows the acquisition of well-defined samples at an affordable cost and allows the determination of air pollution at different time-scales. It reflects longer-term changes of environmental quality, because plant leaves accumulate pollution over months, or even years for evergreen species. Pollutants absorbed by vegetation can also be fixed into the plant system. By phytoremediation, i.e. the use of plants to mitigate pollutant concentrations in contaminated soils, water, or air, several tree species can be used to detoxify urban air affected by a high traffic load (Kvesitadze et al., 2006). Another advantage of a biomonitoring approach is the high spatial resolution that can be obtained.
BIOHYPE: Biomonitoring of urban habitat quality with airborne Hyperspectral observations. (PDF Download Available). Available from: https://www.researchgate.net/publication/263329184_BIOHYPE_Biomonitoring_of_urban_habitat_quality_with_airborne_Hyperspectral_observations [accessed Feb 18, 2016].