Air quality

Some SuDS components (eg trees, green roofs, green walls, swales, basins) can have a positive effect on local air quality, particularly in areas where air pollution is an existing problem (ie air quality management areas). They can absorb or remove certain pollutants, including nitrogen dioxide (NO₂), sulphur dioxide (SO₂), particulates (PM₁₀) and ozone (O₃), providing a number of benefits to people that live, visit or pass through the area, as shown in the benefits pathway diagram below.
Air quality benefits pathway

It is likely that air quality benefits will only be achieved in larger retrofit or redevelopment situations, or in schemes implemented incrementally over time (or where it is reasonable to consider this will happen). The extent to which SuDS components impact on air quality will depend on a range of local factors, including their positioning relative to people being affected, other structures, land form and sources of pollutants, the nature, quantity and size of nearby buildings, and so on.