secondary air pollution PCS

1. KRISHNA KUMAR SINGH
Secondary Air Pollutant
Photo Chemical Smog

2. SMOG
 Originally phrased by Dr.Henry Antoine Des Voeux (1905)
 Names comes from a mix of Smoke and Fog
 First observed in London during the industrial revolution
 There are 2 types of smog: Industrial Smog (London) and
Photochemical (Loss Angeles).s Angeles)

3. Industrial Smog (reducing)
(London Smog)
 Source: Pollution from the burning of coal and oil that contains
sulfur.
 Consists mainly of: Sulfur Dioxide(so2), Sulfur Trioxide(so3), ash
(particulate matter) and sulfuric acid(H2SO4).
 It can cause breathing difficulties in humans, acid rain damage to
plants, aquatic systems, and metal or stone objects.
 London and Chicago have problems with industrial smog .
 Methods of reducing this smog: Alkaline Scrubbers reduce SO2
and SO3 levels;
 electrostatic precipitators reduce particulates.

4.  December 1952 Huge amount of coal Burning 4000 people died of
respiratory problem Followed by additional 8000 deaths in the
following months.

5. Photochemical Smog (Oxidizing)
(Los Angeles smog)
 Source: Mainly automobile pollution.
 Contains: Nitrogen Oxides, Ozone, Alkanes, Peroxyacetyl
Nitrates (PAN).
 Effects: PANs cause eyes to water and can damage plants, O3
irritates eyes and deteriorates rubber and plants, NOx causes
acid rain.
 First observed in LA in the 1940s, Manila and Mexico City also
experience this kind of smog
 Catalytic Converters change NO to N2, Lean burning engines
reduce Nox, but create more CO and Hydrocarbons.

6. Catalytic converter
2NO => N2 + O2
(reduction catalyst)

7. Physical Significance
 Amount of pollutants released into the atmosphere.
 Big problem in developing countries and in many major cities.
Effects
 Plants - reducing or stopping the growth
 Humans - affects heart and lungs even genetic diseases
 Affects materials

8. Photochemical Smog
 Action of sunlight upon the exhaust gases to form pollutants
harmful at low altitudes.
 Mixture of air pollutants
 Nitrogen oxides (NOX)
 Ozone(O3)
 Volatile organic compounds (VOCs)
 Peroxyacetyl Nitrate (PAN)
 A major concern in urban cities-capable of travelling with wind
affecting huge population.

9. Pollutants in
Photochemical Smog
Ozone
 Production at low altitudes.
 NOx from exhaust gases.
 Ozone production is dominant when NO2/NO is greater than 3.
Effects of Ground Level Ozone
 Damage to crops.
 Irritates the respiratory tract and eyes.
 High levels of O3 results in chest tightness, coughing and
wheezing.
 Increased hospital admissions and premature death.

10. PAN(PEROXYACETYL NITRATE)
 Important contributor to photochemical smog.
 Secondary pollutant-formed from other pollutants by chemical
reaction.
 Contributor to production of groundlevel ozone,by transporting
Nox.
 Powerful respiratory and eye irritants and toxic.
 Higher concentrations lead to damage of vegetation.
 Hydrocarbons + O2 + NO2 + light → CH3COOONO2(PAN)

11. Temperature Inversion

13. Formation

15. Summary

16. SOURCES;
 Wikipedia
 Other pdf