AIR POLLUTION
                     AIR POLLUTION
ANALYTICAL MINDS
- A UNIT OF BHUBAN ENTERPRISES
Overview
o Atmosphere as a Resource
o Types and Sources of Air Pollution
• Major Classes of Air Pollutants
• Sources of Outdoor Air Pollutants
• Urban Air Pollution(Photochemical Smog)
o Effects of Air Pollution
o Ozone Depletion
o Acid Deposition
o Controlling Air Pollution 
Atmosphere as a Resource
o Atmospheric 
Composition
• Nitrogen 78.08%
• Oxygen  20.95%
• Argon  0.93%
• Carbon dioxide 0.04%
o Ecosystem services
• Blocks UV radiation
• Moderates the 
climate
• Redistributes water in 
the hydrologic cycle 
Types and Sources of Air Pollution
o Air Pollution
• Chemicals added to the atmosphere by natural 
events or human activities in high enough 
concentrations to be harmful 
o Two categories
• Primary Air Pollutant
• Harmful substance that is emitted directly into the 
atmosphere 
• Secondary Air Pollutant
• Harmful substance formed in the atmosphere when a 
primary air pollutant reacts with substances 
normally found in the atmosphere or with other air 
pollutants 
Major Air Pollutants

Major Classes of Air Pollutants
o Particulate Material
o Nitrogen Oxides
o Sulfur Oxides
o Carbon Oxides
o Hydrocarbons
o Ozone
Particulate Material
o Thousands of different solid or liquid 
particles suspended in air
• Includes: soil particles, soot, lead, asbestos, 
sea salt, and sulfuric acid droplets 
o Dangerous for 2 reasons
• May contain materials with toxic or 
carcinogenic effects
• Extremely small particles can become lodged in 
lungs
Nitrogen and Sulfur Oxides
o Nitrogen Oxides
• Gases produced by the chemical interactions 
between atmospheric nitrogen and oxygen at 
high temperature
• Problems
• Greenhouse gases 
• Cause difficulty breathing
o Sulfur Oxides
• Gases produced by the chemical interactions 
between sulfur and oxygen 
• Causes acid precipitation
Carbon Oxides and Hydrocarbons
o Carbon Oxides
• Gases carbon monoxide (CO) and carbon 
dioxide (CO2) 
• Greenhouse gases
o Hydrocarbons
• Diverse group of organic compounds that 
contain only hydrogen and carbon (ex: CH4- 
methane)
• Some are related to photochemical smog and 
greenhouse gases
Ozone
o Tropospheric Ozone
• Man- made pollutant in the lower atmosphere
• Secondary air pollutant
• Component of photochemical smog
o Stratospheric Ozone
• Essential component that screens out UV 
radiation in the upper atmosphere
• Man- made pollutants (ex: CFCs) can destroy it
Sources of Outdoor Air Pollution
o Two main sources
• Transportation
• Industry
o Intentional forest 
fires is also high
Urban Air Pollution
o Photochemical Smog (ex: Los Angeles below)
• Brownish-orange haze formed by chemical reactions 
involving sunlight, nitrogen oxide, and hydrocarbons 
Formation of Photochemical Smog
Sources of Smog in Los Angeles
Case-In-Point Air Pollution in Beijing 
and Mexico City
o Beijing (left)
o Mexico City (above)
Effects of Air Pollution
o Low level exposure
• Irritates eyes
• Causes inflammation of respiratory tract
o Can develop into chronic respiratory 
diseases
Health Effects of Air Pollution
o Sulfur Dioxide and Particulate material
• Irritate respiratory tract and impair ability of 
lungs to exchange gases
o Nitrogen Dioxides
• Causes airway restriction
o Carbon monoxide
• Binds with iron in blood hemoglobin
• Causes headache, fatigue, drowsiness, death
o Ozone
• Causes burning eyes, coughing, and chest 
discomfort
Children and Air Pollution
o Greater health threat to children than 
adults
• Air pollution can restrict lung development
• Children breath more often than adults
o Children who live in high ozone areas are 
more likely to develop asthma
Graph showing the extent of air pollution 
taken places over the year 2015.
Which cities have been majorly polluted?
Ozone Depletion in Stratosphere
o Ozone Protects earth from UV radiation
• Part of the electromagnetic spectrum with 
wavelengths just shorter than visible light 
Ozone Depletion in Stratosphere
o Ozone thinning/hole
• First identified in 1985 
over Antarctica
o Caused by 
• human-produced bromine 
and chlorine containing 
chemicals
• Ex: CFCs
Ozone Depletion in Stratosphere
o Hole over Antarctica requires two 
conditions:
• Sunlight just returning to polar region
• Circumpolar vortex- a mass of cold air that 
circulates around the southern polar region 
• Isolates it from the warmer air in the rest of the 
planet 
o Polar stratospheric clouds form
• Enables Cl and Br to destroy ozone
Effects of Ozone Depletion
o Higher levels of UV-
radiation hitting the 
earth
• Eye cataracts
• Skin cancer (right)
• Weakened immunity
o May disrupt 
ecosystems
o May damage crops 
and forests
Recovery of Ozone Layer
o Montreal Protocol (1987)
• Reduction of CFCs
• Started using HCFCs (greenhouse gas)
o Phase out of all ozone destroying chemicals 
is underway globally
o Satellite pictures in 2000 indicated that 
ozone layer was recovering
o Full recovery will not occur until 2050
Acid Deposition
o Sulfur dioxide and nitrogen dioxide 
emissions react with water vapor in the 
atmosphere and form acids that return to 
the surface as either dry or wet 
deposition 
o pH scale
How Acid Deposition Develops
Effects of Acid Deposition
o Declining Aquatic 
Animal Populations
o Thin-shelled eggs 
prevent bird 
reproduction
• Because calcium is 
unavailable in acidic soil
o Forest decline
• Ex: Black forest in 
Germany (50% is 
destroyed)
Acid Deposition and Forest Decline
Air Pollution Around the World
o Air quality is deteriorating 
rapidly in developing countries
o Shenyang, China
• Residents only see sunlight a few 
weeks each year
o Developing countries have older 
cars
• Still use leaded gasoline
o 5 worst cities in world
• Beijing, China; Mexico City, Mexico; 
Shanghai, China; Tehran, Iran; and 
Calcutta, India 
Long Distance Transport of Air 
Pollutants
Indoor Air 
Pollution
o Pollutants can be 
5-100X greater 
than outdoors
o Most common:
• Radon, cigarette 
smoke, carbon 
monoxide, 
nitrogen dioxide, 
formaldehyde 
pesticides, lead, 
cleaning solvents, 
ozone, and 
asbestos 
Indoor Air Pollution - Radon
Controlling Air Pollution 
o Smokestacks with 
electrostatic precipitator 
(right)
Without 
Electrostatic 
precipitator
With Electrostatic 
precipitator
Controlling Air Pollution
o Smokestacks with 
scrubbers (right)
o Particulate material can 
also be controlled by 
proper excavating 
techniques
Controlling Air Pollution
o Phase I Vapor Recovery System for 
gasoline
Other Ways to Improve Air Quality
o Reduce sulfur content in gasoline from its 
current average of 330 ppm to 30 ppm
• Sulfur clogs catalytic converters
o Require federal emission standards for all 
passenger vehicles
• Including SUVs, trucks and minivans
o Require emission testing for all vehicles
• Including diesel
The Clean Air Act
o Authorizes EPA to set 
limits on amount of 
specific air pollutants 
permitted
o Focuses on 6 
pollutants:
• lead, particulate 
matter, sulfur dioxide, 
carbon monoxide, 
nitrogen oxides, and 
ozone
o Act has led to 
decreases!
PRESENTATION CREDITS:
DR. TATHAGATA DEB
MR. SHIVAM SAHA
ANALYTICAL 
MINDS
- A UNIT OF BHUBAN ENTERPRISES