Trees and pollution

Trees bring many benefits, including improving the appearance of an area, adding biodiversity, cooling the air, slowing rainfall during storms, contributing to positive mental health and reducing pollution.

Statistics from the Office of National Statistics (ONS) show that people in the Newport and Monmouthshire area spend less than the national average on healthcare, partly due to the large number of trees in the area which filter pollution, resulting in a lower rate of lung and heart related hospital admissions.

In the Newport City Council area there are around 2 million trees and around 200 hectares of woodland.

We aim to retain trees wherever possible and to plant more to increase the number of trees in Newport.  


Particulate matter (PM) consists of particles that are transported in the air, grouped by size which determines how easily and deeply they are transported into the lungs.

Larger PM does not travel as deeply into the lungs as smaller particles.

Diesel engines and burning fossil fuels from power stations contribute to pollution in towns and cities.   

How trees can help

Trees remove PM by a process of dry deposition whereby PM in the air is blown through the tree canopy and becomes attached to the leaves.

Fine PM is attached to the waxy layer on the outside of the leaves, while larger PM sticks to the outer layer and is washed off when it rains, or remains suspended in the air.

Studies debate how much PM tree canopies remove, the main factors influencing the rate of dry deposition are:

1. The concentration of PM - the higher the concentration, the greater the amount of PM that the trees remove

2. The total surface area of the canopy that the PM is passing through

Although trees do not offer a complete solution to the issue of air pollution they are an integral part of the landscape and can help combat pollution issues.

Trees that absorb pollution particularly well are London Plane, Lime, Sugar Maple, Black Pine and Scots Pine.

Newport City Council is committed to tree planting to help reduce pollution in the area.  

Further information

The Nature Conservancy - Planting Healthy Air (pdf)

Forestry Commission – The Case for Trees (pdf)

Forestry Commission – Urban Forestry

Forestry Commission Scotland - The Benefits of Planting Trees (pdf)