1. Class objectives: Cover some of the major topics in Environmental Chemistry Energy Atmospheric Compartment Water compartment Soil

2. Polynuclear Aromatic HC (PAHs) Dioxins Ketones PCBs CFCs DDT O 3, NO 2, aerosols, SO 2 1. Some examples of environmental chemicals

3. Toxic loads Scientists have hypothesized that the fetus is sharing the mother’s toxic load, and may actually provide some protection to the mother by reducing her internal exposure.

4. Children get 12% of their lifetime exposure to dioxins during the 1st year. Their exposure is 50 times greater than an adult during a very critical developmental period.

5. Firstborns from dolphins off the coast of Florida usually die before they separate from their mothers

6. Mother’s milk Human babies nursed by mothers with the highest PCB contamination levels in their milk are afflicted with more acute ear infections than bottle fed Inuit babies. Many of these children don’t seem to produce enough antibodies for childhood vaccinations to take.

7. PCBs and lower intelligence There is evidence of lower intelligence in babies exposed to PCBs. In adults, a blood-brain barrier insulates the brain from many potentially harmful chemicals circulating through the body In a human child this barrier is not fully developed until 6 months after birth.

8. 2. Energy

9. SO what is a joule?? Force = mass x acceleration; f = m x a a =  velocity /  time = dv/dt velocity =  distance /  time; a=  distance /  time 2 Work = force x distance W = f x d W= m x a x d and W = m x d2 d2 /t 2 Work and energy have the same units a joule is defined as accelerating 1 kg of mass at 1 meter/sec 2 for a distance of 1 meter A watt is a unit of power = 1 joule/second or energy/time 

10. how long will the oil last?? 1980 estimate of reserves Oil 1x10 22 J 1980 estimate of oil usage /year 1.35x10 20 J/year Estimate the # years of oil left if we used at the above rate from 1980 to 1990 and 2x’ s the 1980 rate after 1990 = 3x; we estimated ~50 to 80 years We used more recent data in class.

11. Fuel energy  When we burn a fuel where does the energy reside?  Let s take hydrogen in water as an example. If we were to react H 2 with O 2 to form water, we would 1 st have to break the hydrogen bonds and the oxygen bonds  This takes energy; in the case of H 2 it takes 432 kJ/mole (~100,000 calories/mole) for H 2  2H.  How many days of food will supply you with 100,000 calories?  To break O 2 to O. (O 2  2O.) requires 494 kJ/mol  When when water forms, however, we get energy back from the formation of H 2 O because new bonds are formed. Which ones??

12. Combustion energies from different fuels (kJ) react.perperper moles heatmolemolegramCO2 per kJO 2 fuelfuel1000kJ hydrogen 482 482241120 0 2H 2 +O 2  2H 2 O Gas 810 405 810 52 1.2 CH 4 + 2O 2  CO 2 +2H 2 O Petroleum1220 407 610 44 1.6 2 (-CH 2 -)+ 3O 2  2CO 2 +2H 2 O Coal2046 409 512 39 2.0 4 (-CH-)+ 5O 2  4CO 2 +2H 2 O Ethanol1257 419 1257 27 1.6 C 2 H 5 OH + 3O 2  2CO 2 +3H 2 O wood 447 447 447 15 2.2 (-CHOH-) + O 2  CO 2 +2H 2 O

13. 3. Basic concepts Where does pV=nRT come from? At standard state can you calculate R? A+B  C+D ln K eq =-  H/R x 1/T + const.

14. 4. The atmospheric compartment

15. T wo important features the atmospheric Compartment are temperature and pressure

16. Why does the temperature normally decrease with height in the troposphere and increase with height in the stratosphere??

17. The pressure or force per unit area  decreases with increasing altitude  The decline in pressure (P) with altitude is approximately = to log P= - 0.06 (z); where z is the altitude in km and P is bars

18. How thin is the air at the top of Mt. Everest?  Mt. Everest is 8882 meters high or 8.88 km high  log P = -0.06 x 8.88  P = 10 -0.06x 8.88 = 0. 293 bars  Assume there are 1.01bars/atm.  This means there is < 1/3 of the air

19.  Air that contains water is not as heavy and has a smaller lapse rate  and this will vary with the amount of water  If the air is saturated with water the lapse rate is often called  s  Near the surface  s is ~ 4 o K/km and at 6 km and –5 o C it is ~6-7 o K/km The quantity  d is called the dry the dry adiabatic lapse rate

20.  At the equator air is heated and rises and water is evaporated.  As the air rises it cools producing large amounts of precipitation in equatorial regions.  Having lost its moisture the air mass moves north and south.  It then sinks and compresses (~30 o N and S latitude) causing deserts How does air circulate

21.  The mean residence time ( MRT ) can be expressed as: MRT = mass / flux where flux is mass/time  If 75% of the mass/year in the stratosphere comes from the troposphere  1 MRT = ----------------- = 1.3 years – 0.75/year

22.  Mt. Pinatubo in the Philippines erupted in June 1991, and added a huge amount of SO 2 and particulate matter the stratosphere. After one year how much SO 2 was left?  For a 1 st order process C= C o e -1 year/ MRT  C/C o = e -1 year/ MRT = e -1/1.3 = 0.47 or ~ 50%  in 4 years, C/C o = e -4 years/1.3 years = ~ 5%

23.  What happened to global temperatures after the Pinatubo eruption?  A lot of SO 2 was injected into the atmosphere  SO 2 forms fine sulfate particles that reflect light back into the atmosphere and this cools the upper troposphere

25. 5. What is Global Warming and how can it Change the Climate?

27. How fast are green house gases increasing ???  time trace for the concentration of carbon dioxide from 1958-1992 at Mt. Mauna lowa Hawaii  Why does it oscillate up and down as it generally goes up??

30. How fast is Global Warming Occurring ?  The rate of global warming over the next century may be more rapid than any temperature change that has occurred over the past 100,000 years!!!  This will cause major geographical shifts in forests, vegetation, and cause significant ecological disruption

32. 1979 perennial Ice coverage Nat. Geographic, Sept 2004)

33. 2003 perennial Ice coverage

34. Doubling Emissions of CO 2  Often discussed are the effects of doubling CO 2 concentrations from pre-industrial times (2xpre-Ind. CO 2 =550 ppm)  Some times predications are made with the assumption of CO 2 doubling or even quadrupling.  On the next slide you will see world wide emissions using different assumptions.

35. Including Particles in Global Models  Fine particles, especially sulfate particles resulting from SO 2 emissions from coal, combustion can reflect light from the sun and actually cause a negative temp. effect  The next 2 picture from a global circulation model (GCM by Bob Charleston, UW-Wash, USA), shows a cooling effect in the industrialized world. First without considering particles then with  red= +2 o C, yellow =+3 o C, blue = +1 0 C

36. red= +2 o C, yellow =+3 o C, blue = +1 0 C

38. 6. Kinetics: 1 st order reactions A ---> B -d [A] /dt =k rate [A] - d [A]/[A] = k rate dt [A] t = [A] 0 e -kt

39. Some time vs conc. data  Hr Conc [A]Ln[A] 0 2.7181 0.3 2.1170.75 0.6 1.6490.50 0.9 1.2840.25 1.2 1.0000.00 1.5 0.779-0.25

40. A plot of the ln[conc] vs. time for a 1 st order reaction gives a straight line with a slope of the 1 st order rate constant.

41. ln [A]/[A] o =-k t 1/2 ; ln2 /k =t 1/2 2 nd order reactions A + B  products dA/dt = k 2nd [A][B] If B is constant k pseudo 1st = k 2nd [B]

42. ln2 /k =t 1/2 1. constant OH radicals in the atmosphere k pseudo 1st = k 2nd [OH. ]

43. 7. Stratospheric o3 The Stratosphere begins about 10k above the surface of the earth and goes up to 50k The main gases in the stratosphere, as at the surface, are oxygen and nitrogen uv light of low wave lengths ( high energy) split molecular oxygen (O 2 ) to split oxygen O 2  O. + O. requires 495 kJ mole -1 of heat (enthalpy) What wave length of light can do this?? Let’s start with h = E, where h is Planck’s constant and is the frequency of light and E is the energy associated with one photon.

44. And, = c where c is the speed of light and is the wave length of light Combining we can solve for the wave length that will break apart oxygen at an enthalpy of 495,000 J mole -1 = h c/ E If the value of Planck’s constant is 6.62  10 -34 joules sec c = 2.9979 x10 8 m sec -1 = h c/ E = 241 nm can you verify this calculation? Hint energy E is for one photon??

45. Paul Crutzen in 1970 showed that NO and NO 2 react catalytically with O 3 and can potentially remove it from the stratosphere. (he get’s a nobel prize for this in 1995) NO + O 3  NO 2 + O 2 NO 2 + O. -> NO + 2O 2 So where would NO come from?? SST’s

46. CCl 3 F + uv  Cl. +.CCl 2 F but the free chlorine atom can react with O 3 Cl. + O 3  ClO. (chlorine oxides) +O 2 what is really bad is that ClO. + O.  Cl. + O 2 Remember that: O.+ O 2  O 3 (Ozone) It is estimated that one molecule of chlorine can degrade over 100,000 molecules of ozone before it is removed from the stratosphere or becomes part of an inactive compound.

47. Molina found in 1985 that HCl could be stored on the surface of small nitric acid particles in polar stratospheric clouds (PSC). The HCl then just had to wait for a ClO-NO 2 to hit the particle particle  Cl 2 Cl 2 + uv  Cl. + Cl. These nitric acid particles form under extremely low temperatures in polar stratospheric clouds Cl 2 ClO-NO 2 HCl

48. 8. What are aerosols? Aerosols are simply airborne particles They can be solids or liquids or both They can be generated from some of the following sources: 1. combustion emissions 2. atmospheric reactions 3. re-entrainment

49. Cooking stir-fried vegetables: Kamens house, 1987, EAA data

50.  Anthropogenic sources  Primary aerosol Industrial particles 100x 10 12 g/year soot 20 forest fires 80  Secondary aerosols sulfates from SO 2 140 organic condensates 10 nitrates from NO x 36  sum of Anthropogenic 390 x10 12 g/year  sum of natural sources 3070 x10 12 g/year

51. What are some of the terms used to describe aerosols? Diameters are usually used to describe aerosol sizes, but aerosols have different shapes.

52. Often particles are sized by their aerodynamic diameter The aerodynamic diameter of a particle is defined as the diameter of an equivalent spherical particle (of unit density) which has the same settling velocity. It is possible to calculate the settling velocity of a spherical particle with a density =1

53. Fresh wood soot in outdoor chambers (0.5  m scale

54. Gas Particle Partitioning particle toxic gas

55. Langmuirian Adsorption (1918) gas surface  = fraction of total sites occupied Rate on = k on (P g ) (1-  ); Rate off = k off  ; k on /k off = K eq

56. Langmuirian Isotherm if K eq C gas << 1;  = K eq C gas

57. Yamasaki et al.(1982) Langmuirian adsorption Assumes total # sites  TSP (particle conc) log K y = -a(1/T)+ b

58. Yamasaki (1982) Collects Hi-vol filters+PUF Analyzes for PAHs filter PUF log K y 1/Tx1000 BaA

59. Partitioning & uptake by the lungs Nicotine (Pankow’s group)

60. Killer Particles

61. Mortality vs. particle exposure 2.5  m particle conc. in  g/m 3 10203040 mortality ratio 1.0 1.1 1.2 1.3 On a mass basis urban fine particles may be more toxic than cigarette smoke

62. Samet et al. at UNC exposed human airway epithelial cells to residual oil fly ash (ROFA) particles cells secreted prostaglandins Prostaglandins are a class of potent inflammatory mediators which play a role in inflammatory, immune and functional responses in the lung