The main difference between sulphurous smog and photochemical smog is their formation. Sulphurous smog is primarily caused by the combustion of fossil fuels rich in sulphur, resulting in the release of sulphur dioxide and the formation of sulphate particles. On the other hand, photochemical smog forms through the reaction of sunlight with nitrogen oxides and volatile organic compounds, producing ozone and other secondary pollutants.
Sulphurous smog and photochemical smog contribute to environmental degradation. Both can have detrimental effects on human health.
Key Areas Covered
1. What is Sulphurous Smog
– Definition, Formation, Features
2. What is Photochemical Smog
– Definition, PFormation, Features
3. Similarities Between Sulphurous Smog and Photochemical Smog
– Sulfur and Sulfur Dioxide
4. Difference Between Sulphurous Smog and Photochemical Smog
– Comparison of Key Differences
Key Terms
Industrial Smog, London Smog, Photochemical Smog, Sulphurous Smog
What is Sulphurous Smog
Sulphurous smog, also known as London smog or industrial smog, is a type of air pollution primarily caused by the combustion of fossil fuels containing high levels of sulphur compounds. It is typically associated with industrial areas. It has been a significant environmental and public health concern throughout history.
Sulphurous smog is characterized by its yellowish-brown color and the presence of soot or particulate matter suspended in the air. It primarily consists of sulphur dioxide (SO2) and particulate matter. It also contains pollutants emitted from industrial processes, power plants, and residential heating systems. The primary source of sulphur dioxide in the atmosphere is the burning of fossil fuels, particularly coal and oil, which contain high concentrations of sulphur.
The formation of sulphurous smog occurs through a series of chemical reactions. Burning of fossil fuels that contain sulphur release sulphur dioxide into the atmosphere. Sulphur dioxide can further react with oxygen and other atmospheric compounds, such as water vapor, to form sulphuric acid (H2SO4) and sulphate particles. These sulphate particles contribute to the visible haze characteristic of sulphurous smog.
What is Photochemical Smog
Photochemical smog, also known as Los Angeles smog or summer smog, is a type of air pollution that primarily forms through chemical reactions involving sunlight, nitrogen oxides (NOx), volatile organic compounds (VOCs), and other pollutants. It is common in urban areas with high traffic and is a significant environmental and public health concern.
Photochemical smog has a brownish color and creates a hazy atmosphere. It primarily consists of ozone (O3), nitrogen dioxide (NO2), peroxyacyl nitrates (PANs), and other secondary pollutants. The primary sources of pollutants are vehicle emissions, industrial processes, and the evaporation of volatile compounds from solvents and consumer products.
The formation of photochemical smog occurs through a complex series of chemical reactions facilitated by sunlight. It starts with the emission of nitrogen oxides and volatile organic compounds into the atmosphere from various sources. These pollutants react in the presence of sunlight to form ozone and other secondary pollutants. The reactions involve breaking nitrogen dioxide (NO2) into nitrogen monoxide (NO) and atomic oxygen, which then reacts with oxygen molecules to form ozone. VOCs also react with nitrogen oxides in the presence of sunlight, forming PANs and other secondary pollutants.
Similarities Between Sulphurous Smog and Photochemical Smog
- Sulphurous smog and photochemical smog contribute to environmental degradation.
- Moreover, both types of smog can have detrimental effects on human health.
- While the specific formation mechanisms differ, both sulphurous smog and photochemical smog involve the chemical reactions of pollutants in the atmosphere.
Difference Between Sulphurous Smog and Photochemical Smog
Definition
Sulphurous smog is a type of air pollution characterized by a combination of smoke, sulphur dioxide (SO2), and other pollutants. Photochemical smog is a type of air pollution that forms through complex chemical reactions involving sunlight, nitrogen oxides (NOx), and volatile organic compounds (VOCs).
Composition
Sulphurous smog is primarily composed of sulphur dioxide (SO2) and particulate matter, which are byproducts of burning fossil fuels containing high levels of sulphur. In contrast, photochemical smog is composed of secondary pollutants, including ozone (O3), nitrogen oxides (NOx), volatile organic compounds (VOCs), and peroxyacetyl nitrate (PAN).
Formation Mechanism
Moreover, sulphurous smog forms through the oxidation of sulphur dioxide, which is emitted from industrial processes, power plants, and burning fossil fuels. In contrast, photochemical smog forms through the reactions of nitrogen oxides and volatile organic compounds in the presence of sunlight.
Appearance and Location
In addition, sulphurous smog is often characterized by a yellowish-brown haze and is commonly associated with industrial areas where coal or oil combustion occurs. On the other hand, photochemical smog is characterized by a brownish haze and is typically found in urban areas with high levels of vehicle emissions and intense sunlight. It is more prevalent during warm and sunny weather.
Primary Pollutants
In sulphurous smog, the primary pollutants are sulphur dioxide and particulate matter, while in photochemical smog, the primary pollutants are nitrogen oxides and volatile organic compounds.
Conclusion
Sulphurous smog is primarily caused by the combustion of fossil fuels rich in sulphur, resulting in the release of sulphur dioxide and the formation of sulphate particles. On the other hand, photochemical smog forms through the reaction of sunlight with nitrogen oxides and volatile organic compounds, producing ozone and other secondary pollutants. Thus, this is the main difference between sulphurous smog and photochemical smog.
Reference:
1. “Sulfurous smog – air pollution.” Encyclopedia Britannica.
2. “Photochemical Smog.” Byju’s.
Image Courtesy:
1. “Free factory pollution image” (CC0) via Raw Pixel
2. “Photochemical smog formation” By Liweichao.vivian – Own work (CC BY-SA 4.0) via Commons Wikimedia
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