Do Trees Improve Air Quality in Urban Areas?

Heard that trees improve air quality and want to check the facts? You’re in the right place.

We partner with the Woodland Trust and The National Forest to plant hundreds of trees every year, and we know exactly what the benefits are.

Trees are sometimes called the “lungs” of the planet because they absorb carbon dioxide and emit oxygen. They also function as the “liver” of the planet, filtering pollutants from the atmosphere – and this is how they improve the quality of the air around us.

In 2019, 99% of the world’s population lived in a location that didn’t meet World Health Organisation (WHO) air quality guidelines.

Trees play a vital role in wider efforts to make every breath we take better for our health. As London-based luxury floral designers, we’re using our surroundings as an example.

According to Impact on Urban Health, pollution from particulate matter (PM2.5 and PM10) in each London borough is above WHO guidance levels. Planting trees is a vital part of addressing this – something we explore in our journal entry Can Planting Trees Really Help Us Tackle Climate Change?

Each tree planted also improves the quality of the air we breathe.

Trees improve air quality by removing pollutants in two different ways.

Firstly, when concentrated clouds of minuscule particles crash into trees, they disperse and are diluted in the air. This process of dispersion makes it less likely that humans will inhale them.

Secondly, minuscule particles get trapped by waxy and hairy tree leaves. Most of these trapped particles wash away down nearby drains when it rains. This deposition process means fewer minuscule particles in the air we breathe.

Trees are an impressive force of nature because they also provide shade and reduce the ambient temperature, act as a buffer around ancient woodlands that need protection, and support local wildlife by providing shelter and food.

The air purification properties of trees are especially important for human health. Air pollution affects lung development and is involved in developing health conditions such as asthma, emphysema, and other respiratory illnesses. Children, elderly people, and those with existing respiratory issues are most affected, but it is damaging to everyone.

To optimise the effect of trees on air quality, priority locations for tree planting include urban streets, playgrounds, hospital grounds, green spaces in cities, industrial estates, and land around protected habitats.

We’re proud to be part of the London landscape and passionate about protecting the environment around us. Air quality in the city is most affected by road transport and heating systems in homes and businesses. We use green energy in our studio and encourage others to take similar steps.

We’re also keen supporters of tree planting that can help address London’s two most problematic air pollutants, particulate matter (PM) and nitrogen dioxide (NO2), which make breathing difficult and represent a significant public health concern.

The office of the Mayor of London announced a £3.1 million tree-planting package in July 2022. Trees for London is part of the Mayor’s mission to make London a healthier and greener place to live.

Examples of tree planting initiatives in London include an award of £2 million to 56 community projects through the Grow Back Greener Fund in 2022; awards of £75,000 and £500,000 for two major woodland creation and tree planting projects as part of the Green and Resilient Spaces Fund Round 2; 31,000 tree planter packs given to London residents by the Mayor’s office; and 1,000 free rowan trees given to London residents by the Conservation Volunteers (TCV).

Residents and businesses in London can also sponsor a tree.

Since 2016, the Mayor of London has supported planting more than 430,000 trees. Estimates suggest that London’s trees provide at least £133 million of benefits annually through pollution removal, carbon sequestration, and a reduction in water run-off.

You can keep up with the latest developments by signing up for the Environment Newsletter from the Mayor of London.

There are several ways to contribute to helping trees improve air quality. You can join an organisation like The Conservation Volunteers and help with their projects, or provide corporate sponsorship or make personal donations if volunteering isn’t possible.

You can also plant a tree in your own outside space. Urban gardens may be smaller, but there are species well-suited to restricted growing conditions. The Royal Horticultural Society (RHS) has practical advice on trees for smaller gardens.

If you’re concerned about caring for a tree, it’s less demanding than it can seem. The Woodland Trust video below covers how to make a tree protector as a starting point.

If you have time and patience, you can grow your own tree from seed. The Woodland Trust provides step-by-step guidance on how to do this.

Not all trees improve air quality equally. To optimise the air-purifying effects of trees, choosing the right species matters.

Generally, trees that have dense canopies, like pines and conifers, are effective natural air purifiers. The same applies to trees with larger leaves with rough and hairy surfaces.

During a series of wind-tunnel experiments, Barbara Maher and colleagues at the University of Lancaster found that silver birch, yew, and elder trees were the most effective at capturing particles of nine species tested.

Many deciduous trees, like the oak, are less effective at cleaning the air.

Oak, poplar, and willow emit high levels of volatile organic compounds (VOCs), which combine with NOₓ when sunlight is present to produce damaging ozone. Estimates suggest they produce eight times as many VOCs as low-impact trees.

Research in this area is ongoing, but low-impact species are a better choice when planting for air quality, as they are more valuable in improving the air we breathe.

Trees are an integral part of our sustainable ethos at Blooming Haus. Every time we complete a project with wedding couples or event planners, we dedicate a tree to be planted – our way of acknowledging the contribution of our clients and the natural world to our work. We also dedicate a tree to be planted each year we work with a corporate client.

Our commitment to improving air quality through tree planting is informed in part by one of our founders, Michael Dariane, who is a chartered environmentalist.

Tree planting is one of several sustainable working practices at Blooming Haus. We also power our studio using green energy, compost organic waste, avoid non-compostable items and reuse flower buckets and delivery packaging, source flowers locally wherever possible, use probiotic cleaning products, and partner with local businesses using clean-air practices for local deliveries.

Our dedication to sustainability extends to our partnerships with organisations like Ecologi, The National Forest, and the Wildlife Trust, whose work we greatly admire.

For eco-conscious floral design for your event or wedding, we’d be delighted to hear from you. We visit venues in person and work from sketches made on site, ensuring our designs are considered within their setting from the outset.

Get in touch at contact@bloominghaus.com or call 020 3389 9609.

The biggest cause of air pollution in the UK is traffic emissions. Other major causes include power plants, domestic burning, and agricultural processes.

The main pollutants in the air are NO2 (Nitrogen Dioxide) from vehicle emissions, which causes new-onset asthma in children and a decline in lung function in older people; PM2.5, or particulate matter including dust, soot, and droplets of liquid, which can enter the human bloodstream and damage organs; and PM10, larger particles from similar sources that can cause chronic inflammation and lung damage.

Other pollutants that damage our environment include ozone (O₃), sulfur oxides (SOₓ), nitrogen oxides (NOₓ), carbon monoxide (CO), and volatile organic compounds (VOCs).

Interestingly, around 70% of overall pollution is caused by the heating of buildings, construction, and construction-related traffic.

Particulate matter (PM) refers to anything in the air that isn’t a gas. Many particles are tiny and can easily enter the human bloodstream, where they can be transported to organs such as the heart and brain. This poses a serious health risk, especially to children, older adults, and people with respiratory problems.

The particles with the greatest risk are classified as PM2.5 (less than 2.5 micrometres in diameter) and PM10 (less than 10 micrometres in diameter).

The Air Quality Standards Regulations 2010 state that PM concentrations in the UK must not exceed an annual average of 40 µg/m³ for PM10 and 20 µg/m³ for PM2.5. The Environmental Targets (Fine Particulate Matter) (England) Regulations 2023 state that by the end of 2040, the annual average of 10 µg/m³ for PM2.5 should not be exceeded at any monitoring station. An interim target under the Environmental Improvement Plan 2023 for England requires an annual average of 12 µg/m³ for PM2.5 to be met by 2028.

Tree planting forms part of the effort to meet these targets.

There are practical steps everyone can take to help reduce air pollution. Walking, cycling, or car-sharing instead of solo car journeys reduces emissions directly. Using energy-efficient appliances and switching off lights and devices when not in use also makes a cumulative difference.

Planting trees – in your own space or through community initiatives – is one of the most tangible contributions available. You can also advocate for trees when ancient woodland is threatened, and engage your local council on urban tree planting plans.

For further reading on the subject, the websites of The Woodland Trust and Ecosia are both well-resourced starting points.