Question: Does pollution stop the growth of flowers and native plants

Karen Bacon answered on 7 May 2020:

Hi Sadie,
That’s a really interesting question. Firstly, it depends on what type of pollution you mean – particulate matter pollution (like sulphur components from fossil fuels, chared remains of plants from burning and particles emitted by many industries), CO2, nitrogen (often from fertiliser in agriculture but can be a pollutant) or other forms of pollution. Different plants have different tolerances for different types of pollution. For example, one of my favourite plants in Ginkgo biloba (it’s been around since before the dinosaurs and is very useful for palaeobotanical studies; https://en.wikipedia.org/wiki/Ginkgo_biloba) and this is a common street tree in much of the northern hemisphere because it is fairly resistant to particulate pollution; however, it is fairly resistant to dry deposits (e.g. from car exhausts) but much more sensitive when these particles mix with rain to form acid rain. Many plants suffer badly from acid rain – this is really well described in both Germany (when lots of trees in the black forest died due to acid rain mostly caused by industrial emissions; https://sciencing.com/forest-affected-acid-rain-4475.html) and in parts of Canada where a similar problem was observed in forests near mining industries. This is still a problem today in some areas. What happens is that the acid essentially burns the leaves and when enough damage is done, the plants cannot photosynthesise any more so they can’t make food for themselves and die.
Having said that, plants are often very good at filtering out pollution, particularly the dry particles I mentioned before. In this case, the particles get stuck on the leaf surface but do not go into the the leaf and the plants essentially act as filters to remove these particles. SOmetimes plants may shed some leaves if they have become damaged by the pollution but the plant will still survive. Some researchers are now trying to use this to help clean air in cities. This is not a simple solution but it might be able to help (https://www.bbc.com/future/article/20200504-which-trees-reduce-air-pollution-best). Trees in cities are also important habitats and help to keep the cities cooler so trees in cities are really important!
Whether a plant is native or not does not have much to do with how well it can deal with pollution. This tends to depend on the plant’s physiology. Some plants are good at filtering and dealing with pollution, while others are much more sensitive.