secondary air pollution PCS.pptx

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 SO 2 and SO 3 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, O 3 irritates eyes and deteriorates rubber and plants, NO x 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 N 2 , Lean burning engines reduce No x , 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 ( NO X ) 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 NO 2 /NO is greater than 3. Effects of Ground Level Ozone Damage to crops. Irritates the respiratory tract and eyes. High levels of O 3 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 + O 2 + NO 2 + light → CH 3 COOONO 2(PAN)

11. Temperature Inversion

12. Formation

13. Summary

14. SOURCES; Wikipedia Other pdf