As winter nears, smog engulfs many areas of planet Earth. The areas where smog is more prevalent include South and Southeast Asia including countries like China, India, Pakistan, Indonesia, and Mongolia. In Latin America, countries like Mexico, Chile, and Brazil are affected by smog. In North America, both the USA and Canada are impacted by smog, particularly the region of Los Angeles in California. In Africa and Europe, Smog is not as widespread but impacts major cities like London and Lagos.
Smog Definition
Smog is artificial fog created by unnatural causes. The term smog is not old, and no reference regarding smog was found before the 19th century. Smog is the combination of two environmental terms: “smog” and “smoke.” Smog reduces visibility, similar to smog, and causes pollution, similar to smoke. This unhealthy combination of smoke and fog is bad not only for the environment but also for humans, animals, and plants.
Types of Smog
Smog is generally categorized by two factors: its origin and its characteristics. The first type is the photochemical smog, also known as the Los Angeles Smog. The second type of smog is known as Sulfurous smog or the London smog.
Photochemical Smog
Photochemical smog mainly forms in the summer months when the temperature is quite high. This type of smog forms due to reactions between pollutants like NOx and volatile organic substance molecules in the presence of light. These reactions result in the formation of ozone which is a component of smog. It appears mostly in subtropical regions. It mainly consists of oxides of carbon, nitrogen, and other hydrocarbons.
Sulfurous Smog
This type of smog mainly appears in winter months when the temperature is significantly on the lower side. It forms due to SOx produced due to the burning of coal and SOx being emitted by the industry exhausts. However, the formation of this kind of smog requires colder temperatures, therefore, it doesn’t appear in warm regions like tropical areas. Sulfurous smog mainly consists of sulfur oxides and nitrogen oxides coupled with dust particles.
Causes of Smog
The causes of smog are mostly unnatural, as these factors involve human activities. The most common being emissions from factories and vehicles. Brief information on these causes is provided below:
1- Emissions from Exaust
The top cause of smog includes emissions from exhaust due to the burning of hydrocarbons. Hydrocarbons including coal and petrochemicals are today the primary source for producing electricity and heating. Their emissions include pollutants like carbon dioxide, carbon monoxide, NOx, and SOx.
2- Crop Stubble Firing
Another major reason behind the smog in winter months in regions like India-Pakistan is stubble burning. After the cutting of the crop, their stubbles are burned to clear the fields for the next crop. The massive fire produces enormous smoke, resulting in smog in plain areas.
3- Automobiles
Automobiles are probably the top reason behind smog in urban centers of populated countries. The growing population in major cities results in a higher number of vehicles to commute. This overcrowding also results in more concrete infrastructure and fewer green belts. The combination of less greenery and a higher number of vehicles and their exhausts are contributing to smoggy conditions in major cities.
4- Stable weather
Stable weather for a longer duration exaggerates the smoggy conditions. If it doesn’t rain for longer durations, the atmosphere doesn’t clean naturally and pollutants keep accumulating in the air. As a result, smoggy condition engulfs the region.
5- Photochemical Reactions
A major contribution to smog is the chemical reactions between pollutants like NOx and volatile organic substance molecules in the presence of light. These reactions result in the formation of ozone which is a component of smog.
Effects of Smog
Smog impacts human health severely if exposed for a longer duration. To understand the hazard level of smog, we first need to look at the air quality index (AQI). AQI is measured in parts per million (PPM). AQI is considered good when it is below 50 PPM. It becomes moderate when it exceeds 100 PPM. AQI is considered hazardous when it is above 200 PPM. Below are some of the prominent health hazards of smog.
1- Lower Life-expectancy
Long exposure to smog results in premature deaths. This is due to damage of pollutants smog carries including the cancerous components. In the year 2016 alone, nearly 10000 premature deaths were attributed to smog.
2- Respiratory Issues
Pollutants in smog including SOx, NOx, and oxides of Carbon are bad for lung health. Smog causes respiratory issues including asthma and bronchiolitis.
3- Birth Defects
Pollutants present in smog are responsible for various birth defects. Various studies have shown that exposure to smog during pregnancy results in abnormal growth of the baby in the fetus. Similarly, lower-than-normal weight of newborn babies was also observed due to smog-related exposure during pregnancy.
4- Lower Agricultural Yield
Smog reduces the sunlight duration necessary for the normal growth of crops. This results in abnormal growth of crops and lowers their yield.
How to Reduce Smog
It is important to take immediate steps to reduce the impact of smog. Here are some of the steps we can take to reduce the smog.
1- Commute more in public transport rather than private vehicles.
2- Plant as many trees as possible. Trees are the lungs of the environment.
3- Don’t burn the crop stubble or trash.
4- Switching to renewable resources instead of conventional energy sources.
5- Recycle and don’t burn the waste.
6- Use filters on the exhaust of factories.
7- Avoid using crackers and smoke-producing decorations on celebrations.