Secondary Air Pollution: Smog

Secondary Air Pollution: Smog

• Smog is a combination of smoke and fog, describing heavily polluted air in urban and industrialized areas.
• Photochemical smog results from primary pollutants (sulfur and nitrogen oxides) interacting with secondary pollutants (ozone, PANs, nitric acid) in sunlight.
• High vehicle concentrations and sunshine are key factors for photochemical smog formation.
• Major smog-affected cities include Los Angeles, Mexico City, São Paulo, and Beijing.
• Smog formation involves nitrogen and oxygen reacting to form nitric acid and nitrogen dioxide, which gives smog its reddish-brown color. Nitrogen dioxide reacts with hydrocarbons (like methane and carbon dioxide) in the presence of sunlight to create photochemical smog.
• Ground-level ozone is a significant component of photochemical smog.
• Temperature inversions worsen smog conditions by trapping pollutants in lower atmospheric layers.
• Industrial or grey smog comes from burning fossil fuels, producing sulfur dioxide that reacts to form sulphuric acid, creating suspended particles that give it a grey color.

Impacts of Smog

• Smog affects human health, particularly the elderly and those with respiratory illnesses, increasing cases of cardio-respiratory ailments.
• Smog can irritate eyes, limit outdoor activity for children and adults, and harm farm animals.
• Plant productivity can decrease due to smog, causing discoloration and decreased saleability.
• Smog can damage synthetic materials, fade colors in fabrics, and damage paints.

Reducing Smog

• Driving less, especially on sunny days, helps reduce smog.
• Carpooling and alternative fuels decrease emissions.
• Avoiding idling engines and filling petrol tanks during cooler hours reduces gas evaporation.

Smog Components and Formation

• Primary pollutants, like sulfur and nitrogen oxides, are emitted during industrial processes and vehicle exhausts.
• Secondary pollutants, like ozone and PANs, form from the interaction of primary pollutants with atmospheric components in the presence of sunlight.
• The combination of sunlight, nitrogen oxides, and volatile organic compounds (VOCs) contributes to photochemical smog formation.

Explore the phenomenon of smog, a dangerous mixture of smoke and fog that affects urban areas. This quiz covers the causes of photochemical smog, its major components, and cities heavily impacted by this environmental issue. Test your knowledge about air pollution and its effects on our atmosphere.