Smog is air pollution that reduces visibility and is caused by a combination of smoke and fog. It forms when pollutants from vehicles, factories, and other sources are released into the atmosphere and remain suspended under certain conditions. There are two main types of smog: sulfurous smog, which results from high sulfur oxide levels from burning coal and causes London-style smog; and photochemical smog, also called Los Angeles smog, which forms from nitrogen oxides and organic compounds reacting in sunlight to create secondary pollutants. Smog has negative health effects like respiratory issues and is a problem in some Pakistani cities due to industrial and transportation pollution.

1. SMOG
PRESENTED BY : Muzna Kashaf
Roll number : 16261514-030

2. SMOG
• Smog is air pollution that reduces visibility.
• The term "smog" was first used in the early 1900s by H.A. Des
Voeux to describe a mix of smoke and fog over many British
towns.
• It is grimy, dirty, smelly and more dangerous than smoke.
• Smog was common in industrial areas, and remains a familiar
sight in cities today.

3. FORMATION OF SMOG
• Pollutant from automobiles, factories etc. are released into the
atmosphere.
• Under certain conditions of the atmosphere these particles
remain suspended in air.
• Suspended layer forms smog.

4. TYPES OF SMOG
 Two distinct types of smog are recognized:
 Sulfurous smog
 Photochemical smog

5. SULFUROUS SMOG
• Also called as London or Industrial smog.
• It results from a high concentration of sulfur oxides in the air.
• It is caused by the use of sulfur-bearing fossil fuels,
particularly coal.
• Under right conditions smoke and sulfur dioxide can combine
with fog to produce industrial smog.
• In high conc. it is extremely toxic to humans and other living
organisms.

6. PHOTOCHEMICAL SMOG
• It is also known as “Los Angeles smog”.
• It develops when primary pollutants (oxides of nitrogen and other
organic compounds) interact under influence of sunlight
(photochemical reaction).
• This interaction produces mixture of hazardous chemicals called
secondary pollutants e.g. LA smog.
• Burning of fossil fuels like gasoline can also create photochemical
smog.

9. EFFECTS OF SMOG
• Smog is unhealthy to humans and animals, and it can kill plants.
• It causes:
 Coughing and throat or chest irritation.
 Worsening of asthma symptoms.
 Difficulty in breathing and lung damage.
 Heart failure.
 Smog affects everyone differently, and some people are more
susceptible to its negative effects.
 Children, seniors, and people with asthma need to be especially
careful on smoggy days.

11. PRECAUTIONS
• To spend less time outdoors.
• Schedule your outside activities for the early morning or evening,
when ozone levels are low.
• Drive less and walk, bike, carpool, and use public transportation
whenever possible.

12. SMOG IN PAKISTAN
• In recent years, smog has become a problem for some cities in
Pakistan due to industrial and transport pollution.
• The recent smog was observed on 6th November in Lahore as AQI
is recorded as 600.
• Punjab Minister for Industries, Commerce and Investment Mian
Aslam Iqbal in november,2018 said the government was adopting
adequate measures to combat pollution and smog across the
province.
• He maintained that a campaign would be launched on social
media to raise awareness about the damages caused to the
environment by burning of solid waste.

14. THANKS.