Ranchi is one of the 100 cities chosen as part of India’s smart cities program.
Dr. Nitish Priyadarshi
Department of Geology,
Urbanization and migration of people from rural areas to the Ranchi city has badly affected the environment of the city which was earlier known as summer capital of Bihar/ Jharkhand united due to its healthy climate and less pollution. Ranchi is the capital of the Jharkhand, formed in 2000, along with Chhattisgarh, and is one of the 100 cities chosen as part of India’s smart cities program. From the time the state was formed in 2000, the number of vehicles in the city has increased 20 times, contributing to the increase in air pollution. With an increase in population – this erstwhile hill station is now dealing with haphazard construction, insufficient systems for solid waste management leading to open burning and an increase in emissions from transport. Other sources include ones such as the burning of firewood and other organic material for heating and cooking, as well as the open burning of garbage and refuse. The main types of pollutants found in the air in Ranchi would be ones that arise from the number of different combustion sources. These would include materials such as black carbon and volatile organic compounds (VOC's), both of which find origin in the incomplete combustion of both fossil fuels as well as organic material, and as such will be emitted from sources ranging from car engines, factory processes to even the burning of firewood or other raw materials. Some examples of VOC's include chemicals such as benzene, toluene, xylene, methylene chloride and formaldehyde.
Other pollutants would be ones such as nitrogen dioxide (NO2), sulfur dioxide (SO2) alongside polynuclear aromatic hydrocarbons, polychlorinated biphenyls, dioxins, furans and even heavy metals such as lead, mercury and cadmium.
Nowadays, more than half of the human population live in urban areas and this number is increasing. This huge and often unregulated phenomenon has changed dramatically the environmental conditions of previous rural and natural areas, causing atmospheric and acoustic pollution, loss of biodiversity and climatic alterations, with harmful consequences for ecosystem functioning and human health.
Photographs posted here are from different areas near to Ranchi city. From Ranchi city lichens are mostly absent. In forest areas lichens are still found on the rocks, and trees indicating good air quality.
The earliest accounts of the high sensitivities of lichens to atmospheric pollution appeared around the peak of the Industrial Revolution in western Europe. Grindon (1859) in Manchester and Nylander (1866) in Paris both associated the disappearance of lichens from their respective cities with the grossly polluted town air , smoke and sulphur dioxide then being major components of the pollution.
Fresh, clean air is wonderful to breathe in. Without the health risks of air pollution, fresh air feels great for our lungs. Lichens love clean air too- infact their sensitivity to air pollution means they make great air quality indicators.
Basically, lichens depend on atmospheric moisture: rain, fog and dew for growth. There are slow in growth and very sensitive towards the changing environmental conditions. Since, they absorb water and essential nutrients from atmosphere instead of from soil, hence they respond in altered manner to increased concentrations of pollutants in air. Comparison of lichens growth in polluted and healthy environment, a clear cut change in growth as well as addition or reduced growth can be observed.
Like small signposts, these curious organisms can tell us a lot about the air we are breathing. Butterflies, nematodes, frogs, and toads are very good indicators of environmental pollutants, but lichens are easier to study and are quicker to respond to environmental change.
Next time you are on a walk, you can look around for the types of lichens that grow in your area. As a rule of thumb, the smaller the size and less variety of lichens in an area, the more polluted is the environment. Main air pollutants that affect lichen growth are nitrogen, sulphur dioxide, fluorides, ozone, hydrocarbons, and metals such as copper, lead, and zinc.
Lichens look like spots or clumps of colour, like someone has splashed paint onto a branch of a tree. Their colours range from green to brown to white to russet red. Even in these colours, lichens can be understated additions to tree trunks and rocks. Because lichens have no roots or protective surface, they cannot filter what they absorb, so whatever is in the air is taken straight inside. If there are pollutants, it can accumulate in the lichen and can become toxic very quickly.
We breathe in harmless nitrogen gas all the time - in fact it makes up a large part of Earth's atmosphere. But when nitrogren is heated and combined with oxygen (as it is in a car engine), nitrogen oxides are created.
Nitrogen dioxide in the air can be a powerful polluter and becomes harmful for human health in high concentrations.
In high concentrations, sulphur dioxide can irritate the mucus lining of the eyes, nose, throat and lungs. Exposure to sulphur dioxide may cause coughing and tightness in your chest. People with asthma are more sensitive to sulphur dioxide pollution.
Throughout history, people have used lichens for food, clothing, dyes, perfume additives, medicines, poisons, tanning agents, bandaging, and absorbent materials. Compounds unique to lichens are used in perfumes, fiber dyes, and in medicines for their antibacterial and antiviral properties.
Lichens have been used in the treatment of diverse diseases like arthritis, alopecia, constipation, kidney diseases, leprosy, pharyngitis rabies, infection, worm and infestation. The medicinal utility of lichens is regarded to presence of secondary compounds like of usnic acid and atranorin. It is also used in treating wounds, skin disorders, respiratory and digestive issues, and obstetric and gynecological concerns.
Bell, J.N.B. and Treshow, M. (2002). Air pollution and plant life. John Wiley & Sons, Ltd. 309-342.
Grindon, L.H. (1859). The Manchester flora. London: W. White.
Nylander,W. (1866). Les lichens du Jardin du Luxembourg. Bulletin de la Societe Botanique de France 13,364-372