titre:Air quality plants ---- color: #00BCE4 ---- id: airqualityplants ---- imagehead: 19_Symphoricarpos.jpg ---- imagestart: IMG_4989.jpg ---- imageend: ---- text: Achillea millefolium ### Phytoremediation *Achillea millefolium* is one of several species that can colonize soil in urban areas and provide a surface for particle deposition. ### Leaf Plants with hairy and rough leaves can capture a significant amount of particulates. The pinnate hairy leaves of *Achillea* do this work. ### Multiple species Depending upon the species it is planted with, *Achillea* can be more or less sensitive to ozone pollution and damage.
Alchemilla ### Biodiversity In addition to trapping or responding to air pollution, many plants such as *Alchemilla mollis* provide pollen and nectar for pollinating insects. ###Leaf Similar to many plants in this toolkit, *Alchemilla* has hairy leaves that trap particulates. These plants can reduce particulates by up to 60 percent, and nitrogen dioxde by up to 40 percent. ###Clean air gardens *Alchemilla* is a popular plant that can be found in the community clean air gardens in the City of London. One example is at Vestry House on Laurence Pountney Hill.
Amelanchier ### Pop-up garden *Amelanchier* is one of the smaller tree species planted in the Moor Lane Pop-Up Garden, which features air quality plants. ### Trees Trees such as *Amelanchier lamarckii* can mitigate pollutants such as particulates and nitrogen dioxide, as long as the canopies do not trap pollution at street level. ### Wildlife *Amelanchier* is another species that is particularly good for wildlife, providing berries, pollen and nectar for birds and insects.
Aster ### Hyperaccumulator Some plants take up heavy metals from soils. *Aster* is one genus of plants that absorbs metals such as lead, selenium and cadmium, among other soil pollutants. ### Bioindication *Aster* plants can be particularly sensitive to ozone, and will demonstrate the presence of this pollutant through yellowing of leaves and physiological changes. ### Particulates *Aster* plants with hairy and many small leaves can also trap particulates and prevent additional dispersion of this pollutant.
Betula ### Bioremediation Similar to the *Aster genus*, *Betula pendula* is a potent accumulator of heavy metals. Because *Betula* takes up metals, it also remediates soil and air. ### Leaf surface The waxy surface of *Betula* can trap particulates, which often wash into the soil after rain. Particulates can also stay in the waxy surface of *Betula* leaves. ### Mycorrhiza Certain plants such as *Betula* form mycorrhizal associations with fungi when they are under stress from heavy metals, which aid metal uptake.
Convolvulus ### Leaf *Convolvulus* cneorum has small leaves with a large number of fine hairs, which makes it an ideal plant for capturing particulates. ### Clean air planter This plant features in a number of community clean air gardens in the City of London, including in the Lauderdale Tower planters near the Beech Street air quality monitor. ### Flower *Convolvulus* is a flowering shrub originally native to southern Europe. It has white flowers in the spring that attract pollinators.
Erysimum ### Urban habitat Wallflowers are a common plant within the City of London, and they contribute to the area’s biodiversity. Self-seeded wallflowers can be found throughout parks and churchyards. ### Leaf surface The leaf surface of Wallflower has a high number of short hairs, which contribute to the plant’s ability to capture particulates. ### Biodiversity This plant has flowers attractive to pollinators. Wallflower can grow in ruins in association with many plants that make unique urban ecologies.
Euphorbia ### Green walls Green walls can introduce high amounts of vegetation in a vertical space for improving air quality. *Euphorbia* species are well suited to green wall planting. ### Phytoextraction *Euphorbia* is another metal hyperaccumulator, taking up lead and arsenic among other contaminants, potentially to ward off herbivores. ### Nitrogen uptake *Euphorbia* can take up a small amount of nitrogen dioxide. Many (weedy) roadside plant species take up even higher levels of this pollutant.
Geranium ### Leaf surface Geranium has a moderate level of leaf hairs, which contribute to an average particulate uptake. More hirsute plants typically capture more particulates. ### Clean air gardens Geranium is a popular plant in many of the clean air gardens in the City, including at the West Smithfield Cattle Trough and Central Point. ### Pollinators Similar to many plants in the clean air gardens, Geranium has flowers that attract pollinators, thereby contributing to urban biodiversity.
Hebe ### Leaf size *Hebe odora* is an example of a plant that has smooth (or glabrous) leaves, but because the leaves are small they contribute to particulate capture. ### Clean air garden *Hebe* can be found throughout the City, especially at the Moor Lane Pop-Up Garden and Central Point at the Beech Street monitoring station. ### Plant size While plants such as *Hebe* are more efficient in capturing particulates, other larger plants (such as ivy) can capture more particulates overall.
Hedera ### Green walls Ivy is a very popular and common plant in green walls. It has a moderate ability to capture particulates, but due to its size it can capture more particulates than smaller plants. ### Leaf surface While plants with small leaves and needles have greater deposition of particulates, ivy can create extensive green surfaces in urban canyons that greatly reduce pollution ### Resistance Ivy is one of several species that is relatively resistant to urban pollution and urbanisation, making it an ideal plant for air purification.
Heuchera ### Platform 4 *Heuchera* can be found on the Barbican Station’s platform 4, where a community garden of air quality plants has been installed to green the urban canyon of the station. ### Leaf Unlike many of the plants in this toolkit, *Heuchera* has broad leaves. There are hairs on the underside of the leaf surface, which can capture particulates. ### Golden Lane The air quality garden at One Golden Lane features *Heuchera*, which has distinctive purple leaves that are easy to identify.
Lavandula ### Fumifugium In 1661, John Evelyn wrote one of the first air pollution texts for London, noting that plants with pleasant smells could be effective in addressing air pollution. ### Leaf Lavender is an odoriferous plant that can perfume the air. It also has small leaves effective for capturing particulates from further dispersal. ### Clean air gardens Lavender can be found throughout the clean air gardens in the City, including at the Barbican Wildlife Garden.
Osmanthus ### Bioindicator *Osmanthus* is particularly sensitive to pollutants. When exposed to sulphur dioxide, this plant experiences chronic leaf damage, which can be a sign of air pollution. ### Stomata Because of the structure of its leaf and action of its stomata openings, *Osmanthus* does not readily absorb gaseous pollutants. ### Low emission This plant is in the Low Emission Neighbourhood (LEN) planter at Museum of London entrance. The LEN project supports community projects that address air pollution.
Pinus ### Urban pine Pine species can play an important role in capturing particulates, which has led some studies to advocate for increasing the role of pine in urban vegetation. ### Leaf structure Coniferous plants such as Pinus mugo have many small evergreen needles, which are especially effective at capturing particulates. ### Shrubs Because they can be planted by roadsides without creating a canopy that traps pollutants, shrubs such as this one are well suited for air quality planting.
Salvia ### Greening The RHS recommends planting *Salvia*, as a “clean air performer”, in planters and green roofs. It has hairy leaves that are effective for capturing particulates. ### Biodiversity *Salvia* is an example of a plant that is not only good for clean air, but is also beneficial to pollinating organisms, thereby increasing biodiversity. ### Bioaccumulation *Salvia officinalis* has been shown to take up heavy metals such as zinc, although this can cause the wilting of plant leaves.
Sambucus ### Ozone injury *Sambucus* is an example of a plant that is particularly sensitive to ozone. Damage to leaves and growth can be a sign of the presence of ozone. ### Pollution zones In areas with ozone pollution, the change from areas without vegetation to plant communities with *Sambucus* can indicate an improvement in air quality. ### Particulates *Sambucus* has a moderate ability to capture particulates, although it often grows in plant communities that have a high ability to capture particulates.
Sorbaria ### Phytoremediation Shrubs such as *Sorbaria* contribute to the capture of particulates, especially near roadsides. ### Low emission *Sorbaria* can be found in the Low Emission Neighbourhood (LEN) planter at the Museum of London. This planter demonstrates efffective or sensitive air quality plants. ### Ozone injury *Sorbaria* is sensitive to ozone at relatively low levels, and is an effective species for bioindicating the presence of ozone.
Symphoricarpos ### Ozone injury Snowberry is another example of a plant that exhibits leaf injury and impaired growth when exposed to ozone. ### Demonstrator The Low Emission Neighbourhood (LEN) planter at the Museum of London entrance includes Snowberry to demonstrate and test the growth patterns of this plant. ### Bioremediation Snowberry can also capture heavy metals such as iron and zinc. However, the plant will show signs of impaired growth and foliar injury when exposed to heavy metals.
Taxus ### Green screen Yew makes an effective hedge and green screen that can capture significant amounts of particulates, especially near roadsides. ### Leaf structure The small needles of the Yew plant are able to capture a high amount of particulates and prevent onward dispersal. ### BVOCs Yew emits a low level of biogenic voltaile organic compounds, or BVOCs. Some plants emit higher levels, which can contribute to poorer air quality.