Smog is a type of air pollution that combines smoke and fog, resulting in dense, hazy layer of pollution in the atmosphere. Smog is caused by both (i.e. naturally and as a result of human activities) in addition to particulate matter, nitrogen oxides, sulfur dioxide and volatile organic compounds, but it is often caused by smoke emission from vehicles associated emissions (smoke) from industrial processes and the burning of fossil fuels (i.e. petroleum). Smog is especially common in urban areas where traffic and industrial activities are high.
History of Smog
The history of smog goes back centuries, but it became particularly prominent during the industrial Revolution when urban and industrial centers began to emit large amount of pollutants into atmosphere. Here’s an overview of the evolution of smog and its effects over time.
Ancient Civilization
While ancient societies did not produce smog as we know it today, the burning of wool and coal for heating and cooking created smoky environments in densely populated area.
Middle Age:
By the 13th century, London had problems with coal smoke. In 1272 King Edward 1 banned the burning of coal because of fumes. However, enforcing such regulations was difficult.
Industrial Revolution (18th – 19th Centuries)
As industry and coal use increased in 18th and 19th centuries, urban areas such as London became centers of pollution. Factories emit large amount of smoke, sulfur dioxide and other pollutants, causing thick, visible smog.
The Great Smog of London 1952
One of the most infamous smog incidents in history was the Great Smog of London in December 1952. The extreme cold forced residents to burn more coal, which increased pollution level. An anticyclone trapped smoke and fog, creating a thick layer of toxic smog that lasted for 5 days.
This Great Smog caused more than 4,000 deaths and over the next few months up to 12,000 died from respiratory and cardiovascular diseases. The disaster highlighted the severe health effects of smog and led to major changes in air quality legislation.
In response to the Great Smog, Britain introduced the Clean Air Act of 1956, which regulated emissions and encouraged smoke-free zones in urban areas. It is one of the first large-scale efforts to reduce air pollution.
Similarly air quality laws were later introduced in other industrialized countries, such as the United States established the Environmental Protection Agency (EPA) ‘Clean Air Act of 1970’ which determines emission standards for pollutants.
Causes of Smog in Pakistan:
Smoke-emitting vehicles, widespread use of old vehicles with poor emission controls contributes to air pollution. On a Rickshaw statement written ” Smok-emiting vehicles, cause diseases” the same rickshaw emits large quantity of smoke.
Smog is a major environmental and public health problem in Pakistan, especially during the winter months. Mainly due to a combination of vehicular emissions, industrial activities, burning of agricultural residues and unfavorable climatic conditions.
Lahore and Multan are the major cities often experience hazardous air quality. Can be seen as under AQI
Industrial Pollution:
Factories and brick kilns often release fumes into the atmosphere without proper control, which continues to increase the amount of pollution in the atmosphere.
Agricultural Practices:
Burning of crops residues (such as burning stubble from rice harvesting in winter), especially in Punjab, releases particulates and gases that contribute to smog.
Climatic Factors:
During winter, temperature inversion can trap pollutants close to the ground and increasing smog conditions.
Effects of Smog on Environment
Smog has many harmful effects on the environment.
Damage to Plants and Crops:
Ground level ozone, a major component of smog, can damage plant cells, reduce photosynthesis, slows down plant growth and reduces crop yields. Sensitive species, such as spinach, lettuce and wheat are particularly vulnerable to ozone pollution.
Long term exposure to smog can weaken forest ecosystmes by damaging tree vegetation and reducing biodiversity.
Effects on wildlife:
Animals exposed to smog, especially in urban or industrial areas, experiences the same respiratory problems as humans, which can effect their health and reproduction.
Recent developments Health Impact:
In November 2024, around 1.8 million people required medical treatment for respiratory and eye-related diseases due to severe smog in Punjab provinces. The United Nation’s Fund for children (UNICEF) has warned that more than 11 million in region are at risk due to toxic air quality.
Government Initiatives:
The authorities have taken several measures to reduce the effects of smog. Among which the following are worth mentioning.
- Establishment of “Smog War Room” to monitor and control sources of pollution.
- Closing of Schools, parks and museums and public places to protect public health.
- Limiting outdoor activities and advising residents to wear masks.
Smog and Global Impacts:
Today, smog is a major problem around the world,
Current Examples:
especially in industrialized countries such as China and India, where the increasing use of vehicles, industrial development and reliance on coal have exacerbated the smog in these regions.
Pakistan:
Lahore and other cities of Punjab facing significant smog problems due to industrial activities, vehicular emissions and crop burning. Smog is causing widespread health hazardous and visibility problems in these areas of Pakistan.
Smog vs Fog:
Most of us mix the terms Fog and Smog. While this is not the truth
Fog:
Fog is a natural weather phenomenon that occur when water vapors condenses into small water droplets suspended in the air near the ground. Fog forms when temperatures drop below dew point. (the temperature at which air becomes saturated and condenses as humidity increases) It often appears on cool, humid nights or early morning.
Environmental Effects:
Fog is generally harmless and does not cause pollution, however it can disrupt transportation and pose a hazard to drivers.
Smog
While Smog is a type of air pollution that is a combination of smoke and fog, caused by man-made pollution combined with natural moisture or sunlight
How can smog be Controlled?
Although significant progress has been made in controlling smog, ongoing challenges due to Urbanization, Industrialization and Climate Change remains.
- Control Smog : Manage industrial and vehicular emissions with cleaner technologies and stricter inspections.
- Promote Sustainable Transportation: Encourage public transportation, carpooling and electric vehicles to reduce urban pollution.
- Increase Greenery: Plant trees and expand greenhouses to absorb and improver air quality.
- Adopt sustainable Agricultural Practices: Educate farmers on alternatives to burning crops to reduce emissions.
- Enforce Air Quality Laws: Enforce and monitor air quality regulations supported by public awareness and clean energy promotion.
