Rates of particulate pollution deposition onto leaf surfaces: Temporal and inter-species magnetic analyses (original) (raw)
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Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves
Environmental geochemistry and …, 2009
Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the highresolution spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside particulate pollution.
Evaluation and application of biomagnetic monitoring of traffic-derived particulate pollution
Atmospheric Environment, 2009
Inhalation of particulate pollutants below 10 mm in size (PM 10) is associated with adverse health effects. Here we use magnetic remanence measurements of roadside tree leaves to examine levels of vehiclederived PM around Lancaster, UK. Leaf saturation remanence (SIRM) values exhibit strong correlation with both the SIRM and particulate mass of co-located, pumped-air samples, indicating that these leaf magnetic values are an effective proxy for ambient PM 10 concentrations. Biomagnetic monitoring using tree leaves can thus provide high spatial resolution data sets for assessment of particulate pollution levels at pedestrian-relevant heights. Leaf SIRM values not only increase with proximity to roads with higher traffic volumes, but are also w100% higher at 0.3 m than at w1.5-2 m height. Magnetic and SEM data indicate that the particle populations are dominated by spherical, iron-rich particles w0.1-1 mm in diameter, with fewer larger, more angular, silica-rich particles. Comparison of the roadside leaf-calculated PM 10 concentrations with PM 10 concentrations predicted by a widely-used atmospheric dispersion model indicates some agreement between them. However, the model under-predicts PM 10 concentrations at 'urban hotspots' such as major-minor road junctions and traffic lights. Conversely, the model over-predicts PM 10 concentrations with distance from the road wherever one tree is screened by another, indicating the filtering/ protective effect of roadside trees in leaf.
Air Pollution XV, 2007
The use of mineral magnetic concentration parameters (χ LF , χ ARM and SIRM) as a potential particle size proxy for urban street dust collected from Southport (Merseyside, UK) is explored. Correlation analyses between each magnetic parameter and traditional particle size classes (i.e. sand, silt and clay) and respiratory health related size classes (i.e. PM 10 , PM 2.5 and PM 1.0) are reported. Significant relationships (p <0.001; n = 50) exist between sand, silt and clay content with at least one or all of the magnetic concentration parameters. This is also the same for each PM 10 , PM 2.5 and PM 1.0 sizes. Of the three magnetic parameters, χ LF displays the strongest correlation values (r = 0.701, P <0.001, n = 50) and is the most significant parameter, which is consistent with all class sizes of each approach. In doing so, these associations indicate mineral magnetic measurements have considerable potential as a particle size proxy for determining urban roadside particulate matter concentrations. Given the speed, low-cost and sensitivity of the measurements, this suggests magnetic techniques could potentially be used as an alternative and/or complementary exploratory technology for pilot particulate pollution investigations. Furthermore, in certain instances, it could be useful for examining linkages between respiratory health and particulate pollution and vehicle emissions.
Geophysical Journal International, 2008
Elevated levels of airborne particulate matter (PM) are a current problem for air quality in many major metropolitan areas. Many European cities have tightened the PM limits in the air, due to advances in monitoring PM levels. In order to establish guidelines for monitoring and curbing anthropogenic PM output, a better understanding of its origin, composition and diffusion is required. Biomonitoring of magnetic properties of tree leaves has been suggested previously to be a good approach to measure pollution levels in cities both in space and time. We report on a magnetic biomonitoring study of PM in the city of Rome, conducted from 2005 October to December. We collected approximately 180 different sample sets of tree leaves of Quercus ilex, an evergreen oak widely distributed in Rome, at 112 different locations. Specific magnetic susceptibility χ of the leaf is used as a fast, easy and cost-effective proxy to assess levels of primary anthropogenic airborne PM pollution. Highly polluted areas correlate with high traffic areas, with an average susceptibility value of χ = 3.2 × 10 −7 m 3 kg −1 . Low traffic zones are characterized by values more than an order of magnitude lower at χ = 1.4 × 10 −8 m 3 kg −1 , and the background magnetic susceptibility is around χ = 2.6 × 10 −9 m 3 kg −1 . The data show that distance dependence from the source is the most significant factor for the concentration of magnetic PM, and that pollution levels and sources can be reliably delineated by measuring magnetic susceptibility values on tree leaf samples of Q. ilex. A new protocol for magnetic susceptibility measurements is proposed, in order to account for changes due to water evaporation in the leaves as a function of time after collection of the samples. Additional magnetic analyses, such as acquisition of artificial remanences and hysteresis properties, were used to characterize the mineralogy and grain size of the magnetic PM. The results indicate that the population of ferrimagnetic phases have a homogenous composition and grain size throughout the investigated area.
Atmospheric Environment, 1999
We report here the novel use of rapid and non-destructive magnetic measurements to investigate the spatial and temporal pattern of urban dust loadings on leaves of roadside trees. More than 600 leaves were collected from birch trees and their remanent magnetization (IRM 2) determined and normalized for the leaf area. The results show that this normalised 2-D magnetization is dominantly controlled by the tree's distance to the road. The magnetic analyses enabled detailed mapping of the spatial and temporal variations of vehicle-derived particulates. Higher 2D-magnetizations, indicating higher magnetic dust loadings, were measured for leaves collected adjacent to uphill road sections than for those next to downhill sections. This suggests that vehicle emissions, rather than friction wear or resuspended road dust, are the major source of the roadside magnetic particles. Additional magnetic analyses suggest that the particle size of the magnetic grains dominantly falls in the range classi"ed for airborne particulate matter as PM ((2.5 m), a particle size hazardous to health due to its capacity to be respired deeply into the lungs. Thus, the leaf magnetizations relate directly to release into the atmosphere of harmful vehicle combustion products. For leaves from individual trees, magnetization values fall signi"cantly from high values proximal to the roadside to lower values at the distal side, con"rming the ability of trees to reduce aerosol concentrations in the atmosphere. Magnetic analysis of leaves over days and weeks shows that rainfall produces a net decrease in the leaf magnetic loadings.
Fine air pollution particles trapped by street tree barks: In situ magnetic biomonitoring
Environmental Pollution, 2020
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Environmental Pollution, 2013
Recently, biomagnetic monitoring of tree leaves has proven to be a good estimator for ambient particulate concentration. This paper investigates the usefulness of biomagnetic leaf monitoring of crown deposited particles to assess the spatial PM distribution inside individual tree crowns and an urban street canyon in Ghent (Belgium). Results demonstrate that biomagnetic monitoring can be used to assess spatial PM variations, even within single tree crowns. SIRM values decrease exponentially with height and azimuthal effects are obtained for wind exposed sides of the street canyon. Edge and canyon trees seem to be exposed differently. As far as we know, this study is the first to present biomagnetic monitoring results of different trees within a single street canyon. The results not only give valuable insights into the spatial distribution of particulate matter inside tree crowns and a street canyon, but also offer a great potential as validation tool for air quality modelling.
High-resolution magnetic biomonitoring : a quantitative surrogate for particulate pollution
2016
Particulate matter (PM) is the most harmful pollution component widely present in the environment, with no known level at which adverse health effects do not occur. Current estimates are of a 4% increase in mortality, 6% for cardiovascular mortality and 8% for lung cancer mortality per 10 g/m of PM10 (PM10 = < 10 m). However, analysis of causal links between particulate pollution and specific health impacts has been hampered by poor reliability of human exposure data. Exposure assessments tend to be available only at coarse spatial resolution. A new approach, magnetic biomonitoring, may provide a robust, cost-effective means to achieve measurement and sourcing of PM10, at unprecedented spatial resolution. Leaves from roadside trees form natural, widely-distributed pollution collection surfaces, at pedestrian-relevant heights, requiring no power source or protection. The leaves can be analysed magnetically, providing a quantitative proxy for PM10 concentrations, from vehicle com...