Effects of Air Pollution on Plants: Explanation, Damages, Examples

Ans. Acid rain harms trees and causes soils and water bodies to ferment, making water harmful for some fish and other natural life. Depletion of the ozone layer is causing UV radiation to arrive at earth causing skin cancer and also harms crops for example soybeans. It also prompts a decrease in the horticultural yield.

Ans. Due to fossil fuel and industrial combustions that mostly emit nitrogen oxides (NOx) and sulphur dioxide (SO₂) into the atmosphere. Water vapour present in the atmosphere reacts with these gases to form nitric acid and sulphuric acid. Normal rainwater is slightly acidic with a pH range of 5.3-6.0 because carbon dioxide and water present in the air react together to form carbonic acid, which is a weak acid. When the pH level of rainwater falls below this range due to combining with these acids in the atmosphere, it becomes acid rain.

Acid rain has significant effects on the world environment and public health.

• Effect on aquatic environment: Acid rain lowers pH level below 5, most fish eggs cannot hatch. Lowering in pH can also kill adult fish.
• Effect on forests: It makes trees vulnerable to disease, extreme weather, and insects by destroying their leaves, damaging the bark and arresting their growth.
• Effect on soil: Acid rain highly impacts soil microbes and biological activity as well as soil chemical compositions. Thus affecting crop production.
• Effect on architecture and buildings: Acid rain on buildings, especially those constructed with limestone, react with the minerals and corrode them away. This leaves the building weak and susceptible to decay. Irreplaceable damage can be caused to the old heritage buildings.
• Effect on public health: When in the atmosphere, sulphur dioxide and nitrogen oxide gases, degrades visibility and can cause accidents, leading to injuries and deaths. Intensified levels of acid depositions in dry form in the air can cause lung and heart problems such as bronchitis and asthma.
• Other effects: Acid rain leads to weathering of buildings, corrosion of metals, and peeling of paints on surfaces. Acid rain also corrodes metals like steel, bronze, copper and iron.

Ans. Major pollutants are hydrofluoric acid, sulphur oxides, acid rain. The hydrofluoric acid leads to a cellular metabolism disruption of calcium. Sulphur oxides lead to the disturbing mechanism of chlorophyll and acid rain causes deficiencies of minerals which leads to yellowing of the leaves due to leaching of rainwater of the Ca, K and Mg mineral elements.

Ans. An increase in the atmospheric concentration of greenhouse gases has resulted in the rise of atmospheric temperature by 0.6 C . Causes of global warming :

- Increase in concentration of greenhouse gases

- Increase of automobiles and use of fossil fuel.

- Deforestation and change in land use.

- CFC and aerosol emission from refrigerator and aeroplane.

- Increased particulate matter in the lower atmosphere.

Ans. Plants absorb carbon dioxide gas and release oxygen. Thus, they play important role in purifying the earth’s atmosphere. By absorbing CO2 they also reduce the chance of global warming. Trees provide habitat to many birds and animals. They maintain the water cycle in nature and also prevent soil erosion.

Ans. - CO₂ fertilisation effect.

- Many species of plants, being sensitive to temperature will die with a sudden rise in temperature and their places will be taken over by scrub vegetation.

- Loss of biodiversity

- Rise in sea level

-Possibilities of drought and floods

-Eruption of plant disease and pests.

- Change in rainfall pattern

Ans. The inflow of large amounts of nutrients like nitrates and phosphates initially encourages the growth of aquatic organisms, plants and animals. With time as the organic matter increases, debris along with silt piles up at the bottom making the water body shallower and warmer. This leads to the gradual appearance of floating and marshy plants and is eventually converted into the lake. Hence, aquatic life gets severely affected and disrupted.

This phenomenon is called eutrophication. It may be natural or artificial due to the result of human activities.

Ans. The natural ageing of a lake is called eutrophication. In a young lake, there is very little life. Over time, streams drain into it and water becomes enriched with nutrients like phosphate and nitrates.

As a result, phytoplankton and some other plants flourish well. Due to this, the organic matter increases in the lake, water becomes warmer and shallower. Hence, decomposers also start growing.

The high numbers of decomposers make use of the large quantity of oxygen for decomposition. This leads to depletion of dissolved oxygen in the water and mortality of fish and other aquatic organisms. The eutrophied water bodies can lead to Algal Bloom, which further add organic matter to the lake. These consume more oxygen leading to its depletion.

Ans. - Reducing the greenhouse gas emission by limiting the use of fossil fuels and by developing alternative renewable sources of energy

- Increasing the vegetation cover mainly the forests for photosynthesis utilization of CO₂

- Minimizing the use of nitrogen Fertilizers in agriculture for reducing N₂O emissions.

- Developing substitutes of chlorofluorocarbons. 

Ans. Chlorofluorocarbons mainly released in the atmosphere by developed countries, slowly enter the stratosphere and the winds move them towards the poles. Environmental conditions prevailing in Antarctica during winter months, there is no sunlight in Antarctica and extremely low temperature facilitates the formation of ice clouds. During winter, the natural circulation of wind completely isolates Antarctica air from the rest of the world.

The ice clouds provide the catalytic surface for the reaction of chlorine atoms and then ozone. But this degradation of ozone occurs with the return of solar radiation to Antarctica during spring. This results in the thinning of the ozone layer every year over most of Antarctica. This hole disappears in summer due to the warming up of air and mixing up of Antarctica air with that of the rest of the world. Enhanced UV radiations on earth cause: Skin cancer, Blindness and increased chances of cataracts in the eyes, Malfunctioning of the immune system and a higher number of mutations.

Ans. Pure air contains 78% nitrogen, 21% oxygen and 0.03% CO₂. Other gases such as argon, methane, neon, water vapour, etc. are also found in small quantities. When this air is contaminated by unwanted substances which have a harmful effect on both living and non-living things like nitrogen oxide, sulphur oxide, carbon monoxide, etc., is said to be polluted.

Ans. Increased levels of nutrients in the water affect the survival of aquatic organisms as these act as nutrients for algae to flourish and once these algae die, they serve as food for decomposers like bacteria and a huge amount of oxygen in the water body gets used up. This results in decrease in the oxygen level, which may kill aquatic organisms.