Compressed natural gas which was introduced in India is often said to be a green fuel. However, a recent study by Central Pollution Board (CPCB) shows that it is not as safe and environmental friendly as we think it is.
Presence of methane in large amounts
CNG is largely made up of methane, which is one of the Green house gases (GHG). Thus, it is responsible for global warming as well. Although methane in itself is a non-toxic gas, it can create problems for humans when present in greater amounts.
Leakage of CNG through giant transmission pipelines may cause severe problems as it is high in methane. Retrofitted CNG engines produce 30% more methane than originally fitted CNG engines.
Methane can easily displace oxygen from our body and result in a medical condition called asphyxia. Oxygen deficiency for a prolonged period can cause death as well.
Carbon Monoxide Poisoning
The burning of natural gas without proper ventilation produces the poisonous and deadly carbon monoxide gas. It is really difficult to detect it. When present in greater quantities, it may result into carbon monoxide poisoning. Some symptoms of this condition are severe head ache, palpitations, drowsiness, blurred vision and nausea.
Dangerous offshoots produced during processing
The equipments used for processing of CNG may also release air pollutants. For example, separators or other filtering units that remove offshoots and wastes from the gas before it is transported through pipelines for commercial use.
Any leakage or venting of waste gases causes release of volatile organic compounds (VOCs) and other hazardous air pollutants (HAPs). Sulphur dioxide, which is a heavy, colorless and inorganic poisonous gas with a sharp odour, is also released.
Then why is use of CNG promoted and encouraged by the government?
Although CNG is not as clean and safe as it seems but it is definitely better than petroleum and diesel. It can be regarded as the best fossil fuel to use because of this reason.
Combustion of natural gas produces negligible amounts of sulphur, oxides of nitrogen (NOXs), mercury, and particulates. Thus, it reduces the probability of smog formation to a great degree. NOXs are responsible for the formation of acid rain. It reduces the emissions of carbon dioxide significantly. It is because of this reason that Central Pollution Control Board (CPCB) issued a direction to all thermal power plants to switch to CNG in Ghaziabad.
CNG is non-corrosive. Thus, it has less maintenance cost as engines running on CNG would require less servicing. It is cost effective and affordable as well. CNG is gaining a lot of popularity these days due to this reason.
Thus, we must consume CNG cautiously as it does cause air pollution contrary to the popular belief. It is a non-renewable source of energy. We have limited supplies and over consumption of existing resources will only result in environmental degradation.
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