Pollen abortion rates, nitrogen dioxide by passive diffusive tubes and bioaccumulation in tree barks are effective in the characterization of air pollution

This study aims to evaluate the feasibility of using simple techniques – pollen abortion rates, passive diffusive tubes (NO2) and trace element accumulation in tree barks – when determining the area of influence of pollution emissions produced in a traffic corridor. Measurements were performed at 0, 60 and 120 meters from a major road with high vehicular traffic, taking advantage of a sharp gradient that exists between the road and a cemetery. NO2 values and trace elements measured at 0 meters were significantly higher than those measured at more distant points. Al, S, Cl, V, Fe, Cu, and Zn exhibited a higher concentration in tree barks at the vicinity of the traffic corridor. The same pattern was observed for the pollen abortion rates measured at the three different sites. Our data suggests that simple techniques may be applied either to validate dispersion land-based models in an urban settings or, alternatively, to provide better spatial resolution to air pollution exposure when high-resolution pollution monitoring data are not available.

► In order to better estimate exposure of urban dwellers, it is necessary to improve monitoring of small scale gradients of air pollutants.
► Due to its widespread distribution in urban environments, plants could be used to characterize gradients of air pollution.
► Pollen abortion rates and trace accumulation in barks were shown to be capable of detecting gradients of pollution in a small scale spatial distribution and correlated with NO2 levels.
► Plant biomonitoring may be of use to improve exposure estimates of people living at the vicinity of traffic corridors.