Smog is a type of air pollution which can cause changes in visibility. It was initially observed in the 20th century. Smog is a mixture of fog and smoke. Today most of the smoke is photochemical smog. Smog is mainly formed above the urban centres which is composed mainly of tropospheric ozone (O3). The primary particulate matter such as pollen and dust and secondary particulate matter such as sulphur oxides, volatile organic compounds, nitrogen oxides and ammonia gas are also included in the smog.
Smog can cause serious health problems which include difficulty in breathing, asthma, reduced resistance to lung infections, colds, and eye irritation. Ozone in smog also damages plants and trees and also reduces visibility.
What is smog?
Smong known as smog is a mixture of smoke and fog. The smoke usually came from burning coal. Hundreds of different chemicals are present in the smoke which is visible to us consisting of carbon, tar, oil, and ash. The dispersion phase is the only difference between fog and smog. In smoke, the dispersion phase is sold while in fog, the dispersion phase is a liquid. When dust particles mix with air it form smoke. When water vapours condense they form liquid water droplets that hang in the air it is called fog.
What is smoke and fog?
Smoke consists of airborne particles and gases produced by combustion, such as soot and carbon compounds. It is typically associated with sources like industrial processes and wildfires. On the other hand, fog is formed when the air near the ground cools, leading to the condensation of water droplets or ice crystals, significantly reducing visibility. While both can impact visibility, smoke originates from burning processes, whereas fog results from atmospheric moisture condensation.
What is air pollution?
Air pollution refers to the presence of harmful substances in the air, which can have adverse effects on human health, the environment, and other living organisms. These pollutants can be in the form of gases, particulate matter, or biological molecules and may originate from natural processes or human activities. Common air pollutants include particulate matter (PM), ground-level ozone (O3), nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO), volatile organic compounds (VOCs), and heavy metals.
Air pollution can lead to respiratory and cardiovascular diseases, environmental damage, and various health issues. Smog is a specific type of air pollution characterized by a mixture of smoke and fog.
History of Smog
The history of smog can be traced back to the early 20th century when the term “smog” was first coined by Dr. Henry Antoine Des Voeux, a British scientist. In 1905, H.A. Des Voeux used the word to describe the poor air quality in London resulting from a mix of smoke and fog, often originating from burning coal. This early acknowledgement of smog highlighted its presence in industrial areas.
Initially characterized by a combination of smoke and fog with an opaque and odorous nature, smog was a common sight in cities during the early 1900s. The burning of coal contributed significantly to the smoke component of smog. Over time, industrialization and increased urbanization further intensified smog-related issues.
Types of Smog:
There are two types of smog:
- Photochemical Smog
- Sulfurous Smog
1- Photochemical Smog:
It is also called Los Angeles Smog. Photochemical smog is a type of smog that is formed when nitrogen oxides and volatile organic compounds (VOCs) react to sunlight, creating a brown haze above cities. Photochemical smog forms in sunny conditions when pollutants like nitrogen oxides and volatile organic compounds react with sunlight, producing ground-level ozone and secondary pollutants.
2-Sulphurous Smog:
It is a classical type of smog also known as London Smog. It is formed when smoke particles from burning coal combine with fog. This type of smog contains sulfur dioxide and particulate matter. sulfurous smog results from the burning of coal and oil, releasing sulfur dioxide, which, in the presence of moisture, forms sulfuric acid and fine particulate matter.
Both types of smog pose health and environmental risks, emphasizing the importance of controlling pollutant emissions to mitigate their impact on air quality.
Components of Smog:
Smog is composed of various pollutants, and the specific components can vary depending on the type of smog. There are the following common components of smog;
- Particulate Matter: Fine particles are suspended in the air, which have adverse effects on the respiratory health of humans.
- Ozone: It is one of the main components of photochemical smog, which causes respiratory issues and other health problems.
- Nitrogen Oxides (NOx): It is emitted from vehicles and industrial processes contributes to the formation of smog and also has hazardous impacts.
- Volatile Organic Compounds (VOCs): It is released from vehicle exhaust and various industrial activities and increases smog formation.
Global Perspective on Increasing Smog:
Smog is often associated with urban areas, where industries are manufactured, but it can also affect rural regions that are developing. Smog affects the areas that are developing with greater industrial activity and limited air quality management.
The WHO identifies Asia and Africa, specifically cities like New Delhi, Beijing, Lahore, Dhaka, and Cairo, as facing substantial health risks due to severe smog issues and elevated levels of PM2.5. These regions, particularly South-East Asia and the Western Pacific, shoulder 89% of the global premature deaths attributed to outdoor air pollution. Urgent and targeted interventions are imperative to mitigate the pervasive health threats posed by air pollution in these areas.
Geographical Variations Related to Smog:
Smog levels vary based on geographical features topography and meteorological conditions. Areas with limited air circulation experience higher concentrations of smog due to the trapping of more pollutants.
Causes of Smog:
Smog is caused by the interaction of pollutants in the atmosphere arising from human activities. It causes severe health as well as physical problems. The main contributors to smog formation include
1. Vehicle Emissions:
Combusted engines in automobiles release great amounts of pollutants including nitrogen oxides (NOx) and volatile organic compounds (VOCs). These emissions are crucial components for smog formation, particularly the photochemical smog has more hazardous effects on health.
2. Industrial Activities:
Factories and industries release pollutants such as sulfur dioxide (SO2), nitrogen oxides, and particulate matter directly into the air or water without any proper disposal. These substances highly contribute to the formation of smog, especially in areas with high industrial density.
3. Power Plants:
Fossil fuels burning in power plants release high quantities of pollutants like sulfur dioxide and nitrogen oxides directly In the air. These emissions can react with other compounds to form smog.
4. Agricultural Practices:
Agricultural practices can contribute to the formation of smog through certain activities and emissions. Here are some ways in which agricultural practices can be a cause of smog:
- Emissions from Agricultural Machinery: The operation of heavy machinery, such as tractors and combines, in agricultural activities releases pollutants into the atmosphere. These emissions can include nitrogen oxides (NOx), volatile organic compounds (VOCs), and particulate matter, which are precursors to smog formation.
- Agricultural Burning: In some regions, agricultural burning is practised as a means of clearing fields, removing crop residues, or managing agricultural waste. This burning releases significant amounts of smoke, particulate matter, and other pollutants into the air, contributing to smog formation.
- Fertilizer and Manure Management: The use of fertilizers and the management of livestock manure in agriculture can result in the release of nitrogen compounds, including ammonia (NH3), which can react with other pollutants to form smog.
- Pesticide Use: The application of pesticides in agriculture can release volatile organic compounds (VOCs) into the atmosphere. These VOCs can participate in chemical reactions that contribute to the formation of smog.
5. Solvent and Paints:
The use of solvents in paints, coatings, and cleaning products releases vast amounts of VOCs into the air. VOCs combined with other pollutants and when exposed to sunlight contribute to the formation of photochemical smog.
6. Residential Heating and Cooking:
Burning of wood, coal, or other solid fuels for heating and cooking in homes releases pollutants such as particulate matter and carbon monoxide which are hazardous for humans. These emissions can contribute to smog formation, especially in areas with high residential wood burning.
7. Natural Sources:
Human activities primarily contribute to natural sources like wildfires and volcanic eruptions which also release pollutants into the atmosphere directly. However, this emission in the atmosphere indirectly combines with smog and form smog.
8. Topography and Meteorological Conditions:
Geographic features, such as valleys and basins trap the pollutants which lead to higher concentrations of smog. Temperature inversions are where a layer of warm air traps cooler air near the ground level which can also cause smog levels by preventing the dispersion of pollutants.
9. Climate Change and Global Warming:
Climate change has a greater influence on smog formation. Warmer temperatures and changing weather affect the temperature inversions which have impacts on the accumulation of pollutants in the atmosphere. Understanding the sources of smog is crucial for developing effective technologies to improve air quality. Efforts must be made to reduce emissions from vehicles, industries, and other pollution sources to promote sustainable urban planning and cleaner technologies. Innovations play a vital role in addressing the root causes of smog.
10. Temperature Inversion:
When a layer of warm air traps cooler air near the Earth’s surface and prevents the pollutants from rising. This phenomenon leads to the accumulation of smog and worse air quality.
Impacts of Smog
- Smog Effects on Health:
Smog has a direct impact on the respiratory system. Smog can cause asthma, bronchitis, and other respiratory disorders. Long-term exposure to smog can cause cardiovascular issues and lung damage.
Smog contributes to many respiratory and cardiovascular diseases. Increased air pollution level leads to a rise in hospital and medical expenses. These places can cause great economic burdens on both individuals and the healthcare system, with increased costs for medical treatments, medications, and hospital care. Thus smog can cause great economic pressure to the country.
- Environmental Impact of Smog:
Smog has a hazardous impact on the environment. It can harm vegetation and ecosystems. Ozone is a major component of smog which directly damages plant tissues and reduces crop yields. Acid rain resulting from the presence of sulfur dioxide in classical smog also negatively impacts soil, water bodies, and aquatic life as well as the human population.
- Ozone Depletion:
Ground-level ozone is harmful, it’s important to distinguish it from stratospheric ozone, which protects the Earth from harmful ultraviolet (UV) radiation by making a layer between both gases. Smog-related pollutants also contribute to the depletion of stratospheric ozone, and create additional environmental concerns.
- Lost Productivity:
Poor air quality due to smog can cause a decrease in productivity among workers due to various reasons. Respiratory illnesses caused by exposure to smog can result in decreased work efficiency and an overall decline in productivity. Long-term exposure to smog can lead to more severe problems. This can hurt the overall economy of a country.
- Decline in tourism:
Smog can also reduce tourism. Poor air in an area decreases tourists from visiting which leads to a decline in businesses, hospitality and industries. This particularly decreases the association of scenic beauty and outdoor attractions with maturity.
- Increased Energy Costs:
Increased energy costs can result from the effects of smog on various sectors of the economy. For instance, industries and power plants may incur higher expenses in implementing pollution control technologies to meet regulatory standards aimed at reducing smog-forming emissions.
- Property Values:
Areas with consistently high levels of smog experience a decrease rate in property values. People are less interested in investing in areas with poor air quality, thus smog affecting the market in those areas.
- Infrastructure Damage:
Smog contributes to the decline rate of buildings and infrastructure. The corrosive nature of pollutants in the air can accelerate the wear and tear of structures which leads to increased repair costs for infrastructure.
- Regulatory Compliance Costs:
The impact of smog regulatory compliance costs can strain businesses financially, particularly for industries with significant air pollution emissions. Compliance costs include investments in emission control technologies, equipment upgrades, and ongoing monitoring and reporting expenses. These costs can reduce profitability, hinder competitiveness, and potentially lead to job cuts or higher prices for consumers.
Smog impacts on the Economy:
Smog is a type of air pollution that hurts the economy. The economic impacts of smog are diverse in various ways. Smog exerts a multifaceted impact on the economy by escalating healthcare costs through increased illnesses, diminishing workforce productivity due to higher absenteeism, and adversely affecting agriculture, leading to reduced yields and potential financial losses for farmers. Furthermore, smog can discourage tourism, diminish property values in affected areas, and necessitate increased energy costs and regulatory compliance expenses for industries. The global trade of regions grappling with persistent smog issues may also suffer, and while efforts to combat smog can spur innovation in cleaner technologies, they may simultaneously pose transitional challenges for traditional industries.
Impact of Smog on Agriculture:
Smog adversely affects agriculture through several mechanisms. Elevated levels of ground-level ozone in smog can impede photosynthesis and reduce crop yields, negatively impacting important food crops such as wheat, soybeans, and rice. Ozone can also compromise plant resistance to diseases and pests, making crops more susceptible to environmental stressors.
Smog has declining effects on crops and the agricultural system. Ozone which is a major component of smog can damage the tissues of plants and decrease crop yields. This leads to great losses for farmers by affecting the agricultural sector and leading to increased food prices.
The impact of smog on agriculture can be significant and detrimental to crop growth and overall agricultural productivity. Smog can have several negative effects on agriculture:
- Reduced Photosynthesis: Smog can obstruct sunlight and reduce the amount of solar radiation reaching plants. This limits the process of photosynthesis, which is crucial for plant growth and the production of carbohydrates. As a result, crops may experience stunted growth and reduced yields.
- Damage to Plant Tissues: The presence of pollutants in smog can cause damage to plant tissues. Particulate matter can accumulate on plant surfaces, blocking the stomata and inhibiting gas exchange, which hampers the plant’s ability to take in carbon dioxide and release oxygen. This can lead to decreased growth rates and diminished crop quality.
- Increased Stress and Disease Susceptibility: Smog pollutants can weaken plants’ natural defence mechanisms, making them more susceptible to diseases and pests. Ground-level ozone, in particular, can cause oxidative stress, damaging plant cells and impairing their ability to withstand diseases and pests.
- Disrupted Nutrient Uptake: Smog pollutants can interfere with nutrient uptake by plants. For example, high levels of nitrogen dioxide can disrupt the assimilation of nutrients, such as nitrogen and phosphorus, leading to nutrient deficiencies and imbalances in crops.
- Crop Yield Reduction: The cumulative effects of smog on plant growth, photosynthesis, stress tolerance, and nutrient availability can ultimately result in reduced crop yields. This can have severe economic implications for farmers and food availability for the population.
- Soil Degradation: Smog pollutants, when deposited onto the soil, can contribute to soil degradation. Acidic pollutants, such as sulfur dioxide and nitrogen oxides, can acidify the soil, altering its pH balance and nutrient availability. This can negatively impact soil fertility and microbial activity, further compromising crop growth.
To mitigate the impact of smog on agriculture, it is crucial to address and reduce air pollution through effective emission control measures, stricter regulations, and sustainable practices. Additionally, implementing crop management strategies, such as selecting smog-tolerant crop varieties, optimizing irrigation practices, and adopting precision farming techniques, can help minimize the adverse effects of smog on agriculture.
How Global Warming Links with Smog:
Global warming and smog are linked as global warming contributes to the formation of ground-level ozone, a key component of smog. Warmer temperatures and increased sunlight enhance the chemical reactions that create smog. Additionally, global warming can intensify temperature inversions, impeding the dispersion of pollutants and exacerbating smog levels. Climate change can also influence factors that contribute to smog formation.
Some components of smog such as methane and black carbon (soot) contribute to global warming and Male its link with increasing pollution. The warming effect of these pollutants accelerates climate change and further increases the efforts to address environmental challenges.
Control and Prevention of Smog:
There are the following Strategies to control smog
- Reduce the emissions from vehicles and industrial sources
- Implementing strict air quality standards
- Promoting the use of cleaner technologies.
- Public awareness
- Involvement is crucial for enforcing regulations
- Encouraging sustainable practices.
To combat smog and reduce air pollution government should take the following steps:
- Implement strict environmental regulations.
- Industries are required to invest in cleaner technologies
- Comply with emission standards.
These measures are essential for public health, it can lead to increased costs for businesses and profitability.
Urban Planning and Transportation in Controlling Smog:
It includes the following:
- Sustainable urban planning
- Development of public transportation
- Promote non-motorized transport plays a crucial role in reducing smog
- Compact city designs
- Green spaces contribute to improved air quality.
Technological Solutions of Smog:
Advances in control of emission technologies for vehicles and industrial processes.
The promotion of renewable energy sources is essential in decreasing smog. Research and developmental technologies contribute to long-term air quality improvement.
Air Quality Index (AQI):
It is a numerical scale used to check the level of air pollution to the public. It takes into account various pollutants including the association with smog and categorizes the air quality from good to hazardous Regular monitoring and reporting help to raise awareness and prompt action.
International Cooperation:
Air pollution including smog often crosses national boundaries. Collaborative efforts at the international level are crucial for addressing pollution, sharing best practices, and collectively working toward cleaner air globally.
Public Awareness:
- Educating the public about the sources and effects of smog
- Encouraging sustainable behaviours and practices is vital.
- Informed individuals are more likely to support and participate aimed at reducing air pollution.
In summary, addressing smog requires a comprehensive approach involving scientific research, policies, innovation, public awareness, and global cooperation. Efforts should be made to reduce smog not only to improve air quality but also to increase environmental sustainability and public health.
Conclusion:
Smog poses significant challenges and consequences with wide-ranging impacts on the environment, economy and agriculture. The adverse effects of smog on human health, agriculture, productivity, tourism, and infrastructure contribute to a decrease in substantial economic costs. The financial burden associated with healthcare, productivity, and various sectors. There is great importance in addressing air pollution and mitigating smog to address all the possible issues.
To fight smog effectively, a comprehensive approach is required, involving different regulations, technologies, innovation, and awareness. By investing in proper technologies which promote sustainable practices, and policies that reduce emissions by improving air quality, protecting health, and providing economic resilience.
The challenges posed by smog require a collective effort from governments, industries, and individuals for greater results. Sustainable practices, industrial activities, and innovative solutions are crucial to visualize the economic impact of smog and build a healthier and more resilient future for everyone around the world.
Ayesha Khawar
Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad.
