Highlights
- Smog is a deadly amalgamation of highly toxic pollutants
- Smog affects the health of not just humans, also plants and animals
- Instances of smog cover have been seen in London, New York and Beijing
Smog, the word that has been dominating headlines for sometime now given the air pollution crisis in Delhi. A derivative from the merger of the words smoke and fog, the word was first used in 1905 to describe a fog like situation that consists dense, thick smoke, which is caused by industrial emissions making the air heavy with pollutants. The term has since then been regularly used to define situations where smoke from emissions of any kind would create a thick yellowish blanket of suspended pollutants. The contents of smog vary, depending on the materials burnt in a particular region but its effect on respiratory health is deadly.
Formation Of Smog
Smog is formed when burning of fuels, industrial emissions and metals release gases or heavy pollutants such as volatile organic compounds, sulphur dioxide and nitrogen oxides in the air. These then come in contact with sunlight and heat to form fine particles which remain suspended in the air. These are scientifically termed as precursors. The precursors together with air, form smog.
Smog formation is also directly dependent on weather conditions. During temperature inversions warm air stays near the ground and smog is formed as pollutants get trapped in the air. The situation in Delhi has been caused due to pollutants from industries, vehicular emissions getting trapped into air that is already poor and stagnating there.
For Delhi in particular, smog formation is usually speedy because the air is heavily polluted in nature. A dip in air movement results in pollutants being trapped, resulting in heavy smog at the onset of every year, said Anumita Roychowdhury, Executive Director, Air Pollution, Centre for Science and Environment.
Why Is Smog Harmful?
The Delhi air pollution crisis has already been termed as a health emergency by the Indian Medical Association. Smog is highly harmful for not just humans of all ages, but plants and animals as well, as it is made up of toxic pollutants. Smog has been known to cause many deaths, the deadliest count being 12,000 in London in 1952-53. Heavy smog results in decrease in penetration by ultraviolet rays, lowering the production of Vitamin D, a crucial natural element, among living things.
Effects of smog can range from minor pains to deadly pulmonary or cardiovascular diseases. Less intense effects of smog include eye irritation, minor difficulty experienced in breathing, burning sensation on skin, cough and cold. Exposure to smog for prolonged time periods can cause inflammation of tissues in lungs, cancer and even death. Old people, children and pregnant women fall under the high risk group and exposure to smog for prolonged periods can result in cardiac and respiratory complications among these people.
Smog is equally poisonous and harmful for crops and plants. Exposure to smog results in severe infection in plants. A 2014 study by the United States Environmental Protection Agency (USEPA) found that smog severely affected crops like wheat, peanuts, tomatoes, and the toxic elements in these edible items found their way back into the human food chain.
The problem of smog is that it isn’t restricted to surface air only. Smog is absorbed by plants as much as by humans and the toxic elements often find their way back into the human food chain. Prevention of smog is necessary because smog will inevitably affect the lungs and heart once it is formed in a particular area, said Rakesh Mehta, Environmentalist and Ex-Chairman, Delhi Transport Corporation.
Smog Around The World
Smog is a highly worrying environmental concern and the uncontrollable spread of smog over the last few decades across countries has had environmentalists worried at a global level. One of the world’s worst smog covers, popularly known as The Great Smog of 1952 covered London for four days in December, causing 12,000 deaths, following which smokeless zones were enforced in the city where burning of coal was not allowed. A similar deadly smog in New York in November 1966 resulted in the death of 170 people. Following the deadly smog cover, the Clean Air Act was passed in the United States in 1970, which regulated emission levels from industries, vehicles and households. The United States has prevented over 1,60,000 deaths between 2000 and 2010, cases which were a result of air pollution. These deaths were prevented due to timely detection of respiratory diseases, keeping the sick in isolated areas surrounded by clean air and by opting for medical solutions like lung cleansing.
Beijing is one of the worst smog affected cities in the world. Coal burning accounts for 40 per cent of Beijing’s particulate matter (PM) emissions and the city often receives red alerts for excessive smog formation. Cloud seeding, also known as artificial rainfall has been used in Beijing to remove smog from the city. Cars more than 10 years old have also been barred from plying in the city during high smog alerts, since 2017.
While smog is inescapable in modern urban metros, its intensity can be controlled by following a series of norms and regulations. With Delhi coming under smog cover again this year, it is evident that controlling the emission of pollutants was not prioritised over the last one year, despite a similar situation in 2016. As per suggestions by the Central Pollution Control Board (CPCB) in a 2016 report on Delhi’s air quality, smog reduction will only be possible when dust and emission levels are regulated on a large scale and alternate sources of fuel are used widely.
