Question

How can lichens help in indicating the pollutants in air?

Answer 1

Air pollutants dissolved in rainwater, especially sulfur dioxide, can damagelichens and prevent them from growing. This makes lichens natural indicators of air pollution. For example: bushy lichens need really clean air.
Lichens are mutualistic associations of a fungus and an alga and occur as crusty or Continuous  patches or bushy growths on trees, rocks and bare ground. 

- Lichens are very sensitive to sulphur dioxide pollution in the air. Since industrialisation, many lichen species have become extinct in large areas 

- Lichens are widely used as environmental indicators or bio-indicators. If air is very badly polluted with sulphur dioxide there may be no lichens present, just green algae may be found. 

- If the air is clean, shrubby, hairy and leafy lichens become abundant. A few lichen species can tolerate quite high levels of pollution and are commonly found on pavements, walls and tree bark in urban areas. 

- Lichens are injured by sulphur dioxide (SO2).Lichens have also shown sensitivity to some other pollutants, such as heavy metals and Other Gaseous Toxics in Air  , but for the most part lichen damage can be attributed to SO2.

Answer 2

Answer:

hey mate here is your answer

Explanation:

Lichens are regarded as pollution indicators because they are sensitive to sulphur dioxide (SO2) and do not grow in polluted areas. Their presence indicates the absence of pollution in an area, and their absence indicates that the area is polluted.

Hope it helps you.