What is Smog?
Smog is air pollution that reduces visibility. The term “smog” was first used in the early 1900s to describe a mix of smoke and fog. The smoke usually came from burning coal. Smog was common in industrial areas and remains a familiar sight in cities today. Today, most of the smog we see is photochemical smog.
Photochemical smog is produced when sunlight reacts with nitrogen oxides and at least one volatile organic compound (VOC) in the atmosphere. Nitrogen oxides come from car exhaust, coal-fired power plants, and factory emissions. VOCs are released from gasoline, paints, and many cleaning solvents. When sunlight hits these chemicals, they create airborne particles and ground-level ozone or smog.
Ozone can be helpful or harmful. The ozone layer high up in the atmosphere protects us from dangerous ultraviolet radiation from the sun. However, when ozone is near the ground, it is harmful to health. Ozone can damage lung tissue and is particularly dangerous for people with respiratory diseases such as asthma. Ozone can also cause itchy, burning eyes.
Smog is unhealthy for humans and animals and can kill plants. Smog is ugly too. It makes the sky brown or gray. Smog is common in large cities with lots of industry and traffic. Cities in basins surrounded by mountains can have smog problems because the smog is trapped in the valley and cannot be carried away by the wind.
Los Angeles, California, and Mexico City, Mexico both have high levels of smog, partly due to this type of landscape.
Many countries, including the United States, have laws in place to reduce smog. Some laws contain restrictions on what chemicals a factory can release into the atmosphere or when the factory can release them. Some communities have “Burn Days” where residents can burn litter-like leaves in their garden. These limit values for chemicals released into the air reduce the amount of smog.
What are the causes of the smog?
Ground-level ozone is created when sunlight reacts with certain chemicals that come from sources of burning fossil fuels, such as factories or car exhaust. When particles in the air combine with ozone, they create smog. Smog is a type of air pollution that looks like smoky fog and makes it difficult to see.
1. Using Coal as a Fuel
The use of coal as a fuel in heating or power plants releases high concentrations of sulfur oxides into the atmosphere. The effects are made worse by high concentrations of suspended solids in the air and moisture. Burning coal also creates significant amounts of smoke, resulting in smoggy environments.
For example, coal-induced smog was widespread in London until the Middle Ages of the 20th century. In China, Harbin, coal-induced smog contributed to the closure of roads, schools, and airports in the fall of 2013.
2. Vehicular and Industrial Emissions
Emissions from the transport sector, which are caused by the burning of fossil fuels in cars, trucks, buses, motorcycles, and boats, are the main contributors to the formation of smog. Most of the smog formed in large cities is due to traffic emissions.
The industrial processes use a large number of fossil fuels and resources that must be extracted for the manufacture of materials and goods. Therefore, industries cause harmful gaseous emissions and fumes alike, which are released into the atmosphere, leading to the formation of smog.
The main precursors are nitrogen oxides, volatile organic compounds, carbon monoxide, vapors, sulfur oxides, and hydrocarbons. These substances react with moisture, heat, sunlight, and ammonia, among other things, to form the toxic fumes, particles, and ground-level ozone that make up smog.
3. Overpopulation & Excessive Consumption
The world population has grown significantly in the last few decades. This also means an enormous increase in consumption and emissions.
We cannot blame industry alone for the smog problem. It is our overpopulation and consumer behavior that is responsible for excessive smog in our atmosphere. The industry is just trying to meet our requirements.
Since the industrial revolution, machine production has significantly reduced the unit price of material goods, and our consumption has increased significantly as well.
Hence, people can now afford many material things. Since all of these goods have to be manufactured in industrial processes, this also means the emission of harmful gases into our atmosphere. Our consumer behavior therefore plays a major role in the formation of smog.
4. Excessive Waste Production
Our excessive consumption is the main cause of the generation of large amounts of waste. To get rid of this waste, a significant part of it is burned, which leads to the emission of harmful gases into our atmosphere and turns into smog.
Although the occasions for the use of fireworks are rare, a single night of fireworks can result in enormous air and particle pollution, which leads to significant smog. This is especially true on Diwali or New Year’s Eve when a large number of fireworks are used and large cities are covered with a thick layer of smog.
6. Burning of Agricultural Material
In some countries, burning the agricultural field can also contribute to the smog problem. For example, to get rid of old crops and waste from farming practices, farmers often burn them as it is a convenient way to go.
Smog in Delhi, the capital of India, is attributed exclusively to Crop Fires. Around tens of thousands of farmers in the northern Indian states of Haryana, Punjab and Uttar Pradesh used to set their fields on fire with old rice stubble to grow wheat. The practice was banned as it contributed to the mounting pollution crisis in nearby Delhi and across northern India.
The burning of agricultural materials containing ammonia, pesticides, and fertilizers usually implies the emission of gases into our atmosphere, which in later stages turn into smog.
7. Construction Activities
Smog can also occur due to construction activities. A large amount of dirt and dust particles get into the air, especially in areas with a high construction density. This, in turn, can lead to the formation of smog and the associated adverse effects.
8. Natural Causes
Smog can also occur due to natural causes such as a volcanic eruption and some specific effects on plant life. The volcanic eruption releases high concentrations of sulfur dioxide and particles into the air, the two main components for smog formation.
It is believed that levels of radiocarbon from certain plants cause smog in some places. For example, the creosote bush in Los Angeles is linked to smog in the area.
What are the effects of Smog?
Smog can irritate your eyes, nose, and throat. Or it can worsen existing heart and lung problems or perhaps cause lung cancer with regular long-term exposure. It also results in early death. Studies on ozone show that once it gets into your lungs, it can continue to cause damage even when you feel fine
Smog is made up of a combination of air pollutants that can endanger human health, harm the environment and even cause property damage.
Smog can cause or worsen health problems such as asthma, emphysema, chronic bronchitis, and other breathing problems, as well as eye irritation and decreased resistance to colds and lung infections.
The ozone in the smog also inhibits plant growth and can largely damage plants and forests
Who Is Most at Risk From Smog?
Anyone who engages in strenuous outdoor activities, from jogging to handicrafts, can have smog-related health effects. Physical activity makes people breathe faster and deeper and expose their lungs to more ozone and other pollutants. Four groups of people are particularly sensitive to ozone and other air pollutants in smog.
- Children: Active children are most at risk of smog as children spend a lot of time outdoors. As a group, children are also more prone than adults to asthma, the most common chronic disease in children and other respiratory diseases.
- Adults who are active outdoors: Healthy adults of all ages who exercise or work outdoors are at a higher risk of smog.
- People with respiratory diseases: People with asthma or other chronic respiratory diseases are more sensitive and susceptible to the effects of ozone. As a rule, side effects occur sooner and with less exposure than in less sensitive people.
- People with unusual susceptibility to ozone: Some otherwise healthy people are simply more sensitive to the pollutants in the smog than other people and can have more harmful effects on their health from exposure.
Elderly people are often warned to stay indoors on days with heavy smog. Older people, given their age, are unlikely to be at increased risk of the harmful effects of smog. However, like all other adults, older people are at a higher risk of smog if they already have respiratory problems, are active outdoors, or are unusually prone to ozone.
Smog is air pollution that reduces visibility. The term “smog” was first used in the early 1900s to describe a mix of smoke and fog. The smoke usually came from burning coal. Smog was common in industrial areas, and remains a familiar sight in cities today. Today, most of the smog we see is photochemical smog.
Ground level ozone is created when sunlight reacts with certain chemicals that come from sources of burning fossil fuels, such as factories or car exhaust. When particles in the air combine with ozone, they create smog. Smog is a type of air pollution that looks like smoky fog and makes it difficult to see.
Smog can irritate your eyes, nose and throat. Or it can worsen existing heart and lung problems or perhaps cause lung cancer with regular long-term exposure. It also results in early death. Studies on ozone show that once it gets into your lungs, it can continue to cause damage even when you feel fine.