Prof. Dudley Shallcross ACRG Tim Harrison Bristol ChemLabS 2015 FUSION Talk

1. Prof. Dudley Shallcross ACRGTim Harrison Bristol ChemLabS2015 FUSION Talk A Pollutant’s Tale Climate Summit Special Edition

2. 3 most abundant gases in each planetary atmosphere Jupiter H2 (93%) He (7%) CH4 (0.3 %) Saturn H2 (96%) He (3%) CH4 (0.45 %) Uranus H2 (82%) He (15%) CH4 (2.3 %) Neptune H2 (80%) He (19%) CH4 (1-2 %) VenusCO2 (96%) N2 (3.5%) SO2 (0.015 %) Mars CO2 (95%) N2 (2.7%) Ar (1.6 %) Earth N2 (78%) O2 (21%) Ar (0.93 %)

3. Nitrogen NN bond energy = 944 kJ/mol 78% of the atmosphere inert Gas at 25 OC, liquid at – 196 OC TGH

4. Bacterial scrapheap challenge by Dr. Hazel Mottram

5. Oxygen O=O bond energy = 496 kJ/mol 21% of the atmosphere Gas at 25 OC, liquid at -183 OC Photosynthesis is the main source of O2 6CO2+ 6H2O + sunlight  C6H12O6 + 6O2 Carbon dioxide + water + sunlight sugar + oxygen 2H2O2  2H2O + O2 TGH

6. How can you speed up a reaction? We can reduce the activation energy (Ea) of a reaction by using a catalyst TGH H2O2

7. How can you speed up a reaction? H2O2 (aq) + I- (aq)  H2O (l) + OI- (aq) H2O2 (aq) + OI- (aq)  H2O (l) + O2 (g) + I- (aq) Net reaction 2H2O2  2H2O + O2 (I- (aq) is a catalyst here, it is conserved through regeneration and overall it is not consumed)

8. The ozone layer (stratosphere 10-50 km)

10. O O O O O O O O O O

11. Until 1964 the Chapman reactions were thought to be the principal processes governing the ozone balance in the stratosphere. However, measurements indicated that the actual concentration of ozone is smaller than that predicted by about a factor of two to four. Predictions of ozone concentrations by the Chapman mechanism compared with observations at Panama, 1970.

12. Catalytic Ozone Destruction. For a chemical to significantly affect the overall concentration of ozone it either must be present in great abundance or must be involved in a catalytic cycle. Breakthroughs in the 1970’s identified a number of NATURAL catalytic processes that all have the form: X + O3  XO + O2 XO + O  X + O2 net : O3 + O  2O2 Where X = H, OH, NO, Cl or Br.

13. The ozone hole 30th Year since the landmark paper Farman et al. Nature 1985

15. Historic data on (south) polar ozone Area of the hole Ozone minimum

16. CCl4Lifetime ~ 40 (20) years CCl3F Lifetime ~ 45 years

18. Air Pollution 10 km The Tropopause The Boundary Layer 1 km NO, NO2, VOC VOCs ? 0 km Compounds of both biogenic and anthropogenic origin

19. What happens to VOCs (volatile organic compounds)? • Plants and trees emit a vast range of organic material; alkenes, alcohols, carbonyls, acids • Vehicles emit hydrocarbons and aromatic species Many of these species are insoluble and are not rained out, how are they removed? TGH

20. High temperature combustion VOCs can be burned in air (combustion) and oxidised in the process CaC2 + 2H2O  Ca(OH)2 + C2H2 C2H2 + (5/2)O2 2CO2 + H2O CH3OH + (3/2)O2  CO2 + 2H2O The atmosphere oxidises VOCs using free radicals

21. Pollutant removal dominated by the OH radical O3 + h  O (1D) + O2  < ~ 330 nm O(1D) + M  O (3P) + M O(1D) + H2O  OH + OH

22. Ozone Chemistry- low NOx environment O3 + h → O (1D) + O2 λ ≤ ~ 330 nm O (1D) + M → O (3P) + M O (1D) + H2O → 2 OH CO + OH → CO2 + H H + O2 + M → HO2 + M HO2 + O3 → OH + 2O2 Net: CO + O3→ CO2 + O2 Δ[O3] [NOx]

23. Ozone Chemistry- higher NOx environment NO competes with O3 for reaction with HO2 NO + HO2 → NO2 + OH NO2 + h → NO + O(3P) O(3P) + O2 + M → O3 + M Net: CO+ 2O2 → CO2 + O3 Δ[O3] [NOx]

24. Air measurements in Bristol of NO2 Data from 21st January 2001: Combustion is the main source of NO2 TGH

25. Photochemical smog NO2 + sunlight O * + NO  < ~ 400 nm O* + O2 + M O3 + M TGH

26. Photochemical Smog

27. CO2measurements in Bristol CO2 has been measured for several years at the top of Old Park Hill.

28. CO2 measurements at Bristol

29. Longer term CO2 measurements CO2measurements have been made at Mauna Loa for many many years, and show that CO2 has been rising steadily for some time

30. Climate

31. Granny’s model of climate 1 Earth Sun Temperature of the Earth ~ 10o C

32. Big problemo: clouds and ice From sun (100) Scattered back to space by Clouds (24) Scattered back to space by the surface (6) (skiing) Surface Land/water Ice 30% of incoming solar radiation reflected back out to space without being absorbed (Earth’s albedo A = 0.3)

33. Granny’s model of climate 2 Earth Sun With clouds and ice Temperature of the Earth ~ - 18o C

34. Granny is now very cold What can she do to warm herself up? Move closer? Get a blanket?

35. CO2 O3

36. Granny’s model of climate 3 with blankets Earth Sun with clouds and ice and greenhouse gases Temperature of the Earth ~ 16o C

37. Thanks to Mike Stuart 2008 www.disphoria.co.uk For the granny cartoons

38. Secrets in the Ice Secrets in the Ice • Snow accumulation lays down record of environmental conditions • Compacted to ice preserving record • Drill ice core & date

39. CO2 levels over the last 1000 years Gases are extracted from bubbles trapped in ice cores and provide record of past atmospheric concentrations

40. Frog chorus by Dr. Simon Hall

41. Methane (CH4) and Nitrous Oxide (N2O)

42. Increased global temperature

43. Model simulation of recent climate Natural forcings only(solar, volcanic etc. variability) Anthropogenic forcings only(human-induced changes) The Met Office

44. 1.0 Observed simulated by model 0.5 Temperature rise o C 0.0 Hadley Centre 1850 1900 1950 2000 Simulated global warming 1860-2000:Natural & Man-made factors

45. Impacts of Climate on the UK UK will become warmer High summer temperatures more frequent Very cold winters increasingly rare Winters will become wetter and summers may become drier

46. Billion of Tons of Carbon Emitted per Year 14 14 GtC/y Currently projected path Seven “wedges” Historical emissions 7 GtC/y 7 Flat path 0 2105 1955 2005 2055

47. Billion of Tons of Carbon Emitted per Year 14 14 GtC/y Currently projected path Seven “wedges” Historical emissions 7 GtC/y 7 Flat path 0 2105 1955 2005 2055

48. Current technology options to provide a wedge • Improve fuel economy • Reduce reliance on cars • More efficient buildings • Improved power plant efficiency • Decarbonisation of Electricity and Fuels • Substitution of Natural gas for coal • Carbon capture and storage • Nuclear fission • Wind electricity • Photovoltaic electricity • Biofuels

49. Improve fuel economy Increase fuel economy for 2 billion cars from 30 to 60 mpg A typical car emits a ton of carbon into the air each year If a fuel efficiency of 60 mpg was achieved, decarbonisation of the fuel would offer the potential of saving two wedges Double the fuel efficiency of the world’s cars or halve miles traveled

50. More efficient buildings Need to cut the carbon emissions from buildings by 25% by 2055 This can be achieved using known and established approaches to energy efficiency The largest savings are in space heating and cooling, water heating, lighting, and electric appliances. Replacing all the world’s incandescent bulbs with compact fluorescent lights would provide 1/4 of one wedge