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Version 2.2 by Emily West on 2022/01/10 14:39
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Emily West 1.1 1 = 2.1.3 AAPCV - Annual Amount of Pollutants Captured by Vegetation =
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5 |=(% style="width: 79px;" %)Topic|=(% style="width: 139px;" %)Urban challenges|=(% style="width: 666px;" %)Sub-challenges
6 |(% style="width:79px" %)Environment|(% style="width:139px" %)2 - Air Quality|(% style="width:666px" %)2.1.1 Air Quality at District/ City Scale
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10 ====== **Description** ======
11 )))|(% style="width:730px" %)Annual amount of pollutants captured by vegetation indicates the amount of particulate and gaseous emissions through deposition and dispersion. Trees affect air quality through the direct removal of air pollutants, altering local microclimates and building energy use, and through the emission of volatile organic compounds (VOCs), which can contribute to O3 and PM2.5 formation. However, integrative studies have revealed that trees, particularly low VOC emitting species, can be a viable strategy to help reduce urban O3 levels. Trees remove gaseous air pollution primarily by uptake via leaf stomata, though some gases are removed by the plant surface. For O3, SO2 and NO2, most of the pollution is removed via leaf stomata. Once inside the leaf, gases diffuse into intercellular spaces and may be absorbed by water films to form acids or react with inner-leaf surfaces. Trees directly affect particulate matter in the atmosphere by intercepting particles, emitting particles (e.g., pollen) and resuspension of particles captured on the plant surface. Some particles can be absorbed into the tree, though most intercepted particles are retained on the plant surface. The intercepted particles often are resuspended to the atmosphere, washed off by rain, or dropped to the ground with leaf and twig fall. During dry periods, particles are constantly intercepted and resuspended, in part, dependent upon wind speed. The accumulation of particles on the leaves can affect photosynthesis and therefore potentially affect pollution removal by trees. During precipitation, particles can be washed off and either dissolved or transferred to the soil. Consequently, vegetation is only a temporary retention site for many atmospheric particles, where particles are eventually moved back to the atmosphere or moved to the soil.
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13 ===== **Scale as linked to D2.2 framework** =====
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15 * National
16 * City
17 * Neighborhood
18 * Street
19 * Household
20 * Object
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23 ====== **Data source [ link to data framework]** ======
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25 * Municipalities and institutes responsible for statistics and forests (for the area covered by vegetation and the species)
26 * Literature and other references (for the capture potential of different vegetation types)
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29 ====== **Needs** ======
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31 * Area coverage of certain vegetation types
32 * Capture potential of vegetation types (calculated from deposition velocity, pollutant concentration and properties specific to species e.g. LAI)
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35 ====== **Expected Outputs** ======
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37 * Annual measurement
38 * unit: t pollutant per ha/year
39 * Quantitative
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42 ====== **Calculation methods** ======
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44 * **Tiwary method:** An integrated modelling approach which utilises air dispersion (ADMS-Urban) and particulate interception modelling (UFORE) to predict the PM10 concentrations both before and after greenspace establishment, using a 10x10 km area of East London Green Grid (ELGG) as a case study.
45 * **Mapping air purification** using spatially-explicit data on ecosystem types and characteristics (particularly Leaf Area Index LAI), and pollution distribution.
46 * **Forest Inventory Analysis (FIA):** estimation of pollutant capture via using the data from FIA lichen indicator. FIA lichen indicator shows the intensity of lichens in a forest that are tolerant to a specific pollutant.
47 * **I-Tree Eco method** is based on creating a detailed urban forest inventory and calculating structural indicators (LA, LAI) or regulating ecosystem services (Cseq, air pollution removal, water retention). The latter need detailed meteorological and pollution datasets.
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50 ====== **Links and references** ======
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52 * An impact evaluation framework to support planning and evaluation of nature-based solutions projects, An EKLIPSE Expert Working Group report, 2017, Centre for Ecology & Hydrology, UK.
53 * Nowak et. al., 2014. Tree and forest effects on air quality and human health in the United States. Environmental Pollution 193, pg. 119-129.
54 * Tiwary et. al, 2009. An integrated tool to assess the role of new planting in PM10 capture and the human health benefits: A case study in London. Environmental Pollution 157, pg. 2645–2653
55 * Forest Inventory and Analysis, Fiscal Year 2013 Business Report. 2014, United States Department of Agriculture Forest Service
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