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PHOTOCHEMICAL SMOG DISCOVERED

PHOTOCHEMICAL SMOG DISCOVERED. TRANSFORMATION. The 20 th century has been characterised by a transition from urban air dominated primary pollutants to one where secondary pollutants are very important. . Who Framed Roger Rabbit?. LOS ANGELES EARLY 1940s. Vanishing streetcars.

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PHOTOCHEMICAL SMOG DISCOVERED

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  1. PHOTOCHEMICAL SMOG DISCOVERED

  2. TRANSFORMATION • The 20th century has been characterised by a transition from urban air dominated primary pollutants to one where secondary pollutants are very important.

  3. Who Framed Roger Rabbit? LOS ANGELES EARLY 1940s • Vanishing streetcars

  4. Eye irritation A 1943 smog Butadiene plant LOS ANGELES EARLY 1940s • Air pollution so bad baseball games not visible • Japanese gas attacks • Southern California Gas Company’s artificial rubber plant - butadiene http://www.aqmd.gov/news1/Archives/History/marchcov.html

  5. Raymond Chandler’s Philip Marlowe LOS ANGELES in FICTION • Smog appears, but actually not in Chandler till 1953

  6. LOS ANGELES mid 1940s • Post war: smog problem still serious • LA administration suggests it will take a few months to solve • Tucker invited from St Louis – he’d been successful in solving Pittsburgh’s problems • The automobile not really a problem – no sulfur in petrol

  7. February 12 1951 1950’ SMOG and LIFE

  8. LIFE article “Now industrialisation has caught up with Los Angeles to the extent that it has its own special brand of smog – less grim, but more eye-burning chemicals…” Good esrly video at: http://www.arb.ca.gov/html/brochure/history.htm

  9. A RADICAL IDEA • Arie J Haagen-Smit – biochemist concerned with crop damage • Smelling the air – like an organic chemistry lab • “action of sunlight and automotive vapours”

  10. DOMINANCE of the AUTOMOBILE • Haagen-Smit opposed by auto manufacturers • Initiated study at Stanford Research Institute • The now classical understanding derives: • P.A. Leighton, Photochemistry of Air Pollution (1961) • and more fully Heicklen, Westberg and Cohen (1969/71)

  11. NO + O3  NO2 + O2 (R1) NO2 + hν  NO + O (R2) O + O2  O3 NO + O3  NO2 + O2 + hv • “action of sunlight and automotive vapours” NOX PSUEDO-EQUILIBRIUM

  12. NOX PHOTOSTATIONARY STATE“EQUILIBRIUM” R1= - k NOO3 k=0.38ppm-1s-1 R2 = -k h NO2 = -JNO2 NO2 JNO2 photolysis rate, s-1 JNO2 NO2 = k NOO3 JNO2NO2/k NO O3 = 1 = p

  13. MODEL VSREALITY

  14. MODEL VS REALITY

  15. O3 + NO NO2 + O2 NOX PSUEDO-EQUILIBRIUM x hv …the nature of X forms a major part of what controls smog formation • “action of sunlight and automotive vapours”

  16. ROLE OF “AUTOMOTIVE VAPOURS” CH4 + OH  CH3 + H2O CH3 + O2 CH3O2 CH3O2 + NO  CH3O + NO2 CH3O + O2 HCHO + HO2 HO2 + NO  OH + NO2 CH4 + 2O2 + 2NO  HCHO + 2NO2 + H2O

  17. THE RADICAL IDEA • In a submission to Industrial and Engineering Chemistry: Haagen-Smit refers to both ozone and peroxides • Significance not quite clear?

  18. RO2 O3 + NO NO2 + hv OVERALL CHEMISTRY CH3CH3 + 2O2 + 2NO  CH3CHO + 2NO2+ H2O ethane (alkane) acetaldehyde • “action of sunlight and automotive vapours”

  19. ACETALDEHYDE CH3CHO + OH  CH3CO + H2O CH3CO + O2 CH3COO2 CH3COO2 + NO  CH3CO2 + NO2 CH3CO2  CH3 + CO2 CH3COO2 + NO2 CH3COO2NO2 Breaking and re-entry Formation of Peroxyacetylnitrate (PAN)

  20. EYES, POLLUTION and Optrex “Treat your eyes to some TLC, • dusty, smoky atmospheres • city air pollution • drying atmosphere of air conditioning”Ad in London underground Peroxyacetylnitrate Particle deposition on eyes

  21. A LONG AND DIFFICULT PROBLEM Ozone at Crestline California

  22. GOING BEYOND LA! • Liquid fuels • Mobile sources • Multiple polluters

  23. NOT SO MUCH IS AIR POLLUTION GETTING WORSE…ITS CHANGING! WOOD SMOKE VOCs, O3 COAL SMOKE DIESEL SMOKE SMELLs LEAD H2S TIME

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