You might have known that air pollution will be severe in winter, How severe will it be ? And why it is so ? What is Smog ?
SMOG – The science behind it
Smog is a solid-liquid colloidal particle consisting of smoke and fog. This prevents the smoke from dispersing and making it to concentrate at lower heights.
Among the many sources of air pollution like vehicular, smoking, cooking etc, lets study the industrial chimney for easy understanding of Smog phenomenon. Factory/industrial chimneys are designed such that the gases will not reach the surface of the earth and even if it reaches the surface, its concentration will be reduced by dispersion to life bearable capacity. The concentration should comply the National Ambient Air Quality Standards set by the Central Pollution Control Board (CPCB) that is applicable nationwide. The CPCB has been conferred this power from the Air (Prevention and Control of Pollution) Act, 1981.
The concentration of pollutant, wind speed of the locality, volume and flow of the pollutant are considered while designing these types of chimneys. At the first step in chimney, water is sprayed to capture the bigger Particulate Matter like PM10 by the principle of lodging. Then Electro Static Precipitators (ESP) is used to capture the little smaller Particulate Matter like PM2.5 using the potential difference. Then scrubbers are used to capture few extent of SOx, NOx and other harmful gases. Then remaining pollutant is released to the atmosphere.
Why one should worry in Winter ?
One can say that rainy season is the clearest season as it pushes all the air pollutants to the ground by dissolving in moisture. In windy season, it obviously helps the pollutants to get dispersed thus the pollutant concentration will be reduced faster. What about the summers? According to Thermosyphon Rule, hot (low density) particles goes up and cold (high density) particles settles down. This is the reason why water boggles while boiling in a bowl. The heated water will go up and the cold water will go down, then it gets heated to come up. This cycle continues. Similarly in summers, the hot gases are pulled up naturally thus it helps the polluted air to fly high thus it gets dispersed easily and out of the life area. But in the winter, it cools the pollutant, increases its density and brings it down to the surface.
This is why, winters act similar to green house effect that won’t allow the pollutants to escape the surface. Instead of dispersing the pollutant it gets concentrated. This is known as air inversion that leads to continuous increase of concentration of air pollutants of a locality.
Winter acts similar to green house effect that wont allow the pollutants to escape the surface. Instead of dispersing the pollutant it will get concentrated. This is Known as air inversion that leads to continuous increase of concentration of air pollutants of a locality
Calamities due to Air pollution
1948 Donora smog
It was a historic calamity, due to air inversion, a wall of smog came into the city and killed 20 people immediately and made 7000 people were taken ill. The mortality rate of Donora, Pennsylvania was very high even after 2o years. You may refer to the Bhopal Gas Tragedy. But it is a toxic substance leakage. Donora is refered to be a Air Quality Calamity.
Yamuna Expressway, Delhi:
Unlike water pollution, it is tough to find the source of air pollution. Though the possible sources are as follows:
- Vehicular Pollution
- Cracker Impacts
- Burning of leftover crop plants by the farmers
- Garbage burning (More than 12 non-engineered landfills are there in Delhi. Delhi acts as a bad example of waste management. And most of these landfills are inside the city. As landfills generate methane, often they catch fire and pollutes the air)
The condition in Delhi is worsening day by day. On the first anniversary of demonetization, 27 cars crashed due to reduced visibility due to smog, 1 died, many injured. It is visible to our naked eyes that we have to be afraid of air pollution as we were afraid about the rains, tsunami, cyclones etc. From this winter, avoid burning wastes, reduce vehicle usage and such smoke generating activities, Use public vehicles, stay safe and beware of the impacts. It is the time to be alert from the man-made calamity.
Smoke from the Capital is obviously not a good sign.
The Winter is Here, and it breached the North ;P