University of Maryland 2. NASA Goddard Space Flight Center 3. Johns Hopkins Applied Physics Laboratory 4

Transcription

1 Improvements in Surface Ozone in the Eastern U.S. During the Past 4 Decades: Success of Air Quality Regulation Revealed by Surface, Satellite and Emission Monitoring Ross Salawitch 1, Kyle Hosley 1, Tim Canty 1, Linda Hembeck 1, Hao He 1, Russell Dickerson 1,Nickolay Krotkov 2, Lok Lamsal 2, William Swartz 3, K. Folkert Boersma 4, Henk Eskes 4, Helen Worden 5, Merritt Deeter 5, David Edwards 5, John Gille 5, Andreas Richter 6, John Burrows 6 and DISCOVER-AQ Science Team 1 University of Maryland 2 NASA Goddard Space Flight Center 3 Johns Hopkins Applied Physics Laboratory 4 Royal Netherlands Meteorological Institute, De Bilt, The Netherlands 5 National Center for Atmospheric Research 6 University of Bremen 5 June

2 Significant Improvements in Air Quality since early 1980s 2

3 Probability of Surface O 3 Exceedance: DC, MD, and Northern VA Catalytic Converters Mandatory Low NOx burners 1990 CAAA Phase 1 SCR Scrubbing of NOx from Power Plants (SIP) 3

4 Probability of Surface O 3 Exceedance: DC, MD, and Northern VA Catalytic Converters Mandatory Reformulated Gasoline 1990 CAAA Phase 1 SCR Scrubbing of NOx from Power Plants (SIP) 4

5 BWI T > 90 F Analysis in this framework motivated by Pusede and Cohen, ACP,

6 BWI T > 90 F Analysis in this framework motivated by Pusede and Cohen, ACP,

7 BWI T > 90 F VOC Limited Regime NO x Limited Regime Analysis in this framework motivated by Pusede and Cohen, ACP,

8 Surface NO x Power Plant NO x Hao et al., ACPD,

9 Hao et al., ACPD,

10 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on all O 3 data Lower Fifth of O 3 PDF based on all O 3 data Upper Fifth of CO PDF 10

11 Two plausible explanations for narrowing of the surface O 3 distribution: a) O 3 titration Historical measurements of very low O 3 could be due to O 3 removal from system when NO x was extremely high b) Rise in background O 3 O 3 levels in free trop over Western N. America have been rising, and this rise has been linked to Asian emissions Zhang et al. (2011) calculated influence of Asian emissions weakens considerably in eastern U.S. Seasonal mean, policy relevant background (PRB) surface O 3 for spring and summer 2006 found using GEOS-Chem. PRB O 3 ound by zeroing out North American emissions. 11

12 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on all O 3 data Lower Fifth of O 3 PDF based on all O 3 data Upper Fifth of CO PDF 12

13 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on availability of CO Lower Fifth of O 3 PDF based on availability of CO 13

14 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on availability of CO Lower Fifth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 14

15 SCIAMACHY NO 2 over Greenbelt, MD Unshaded rectangles: surface ozone season, 1 April to 30 Sept Slopes found for Apr to Sep SCIA In Situ 10.5 ± 1.8 % year ± 0.9 % year 1 Surface data: SCIAMACHY Overpass Satellite data: Cloud Fraction <

16 OMI NO 2 over Greenbelt, MD Unshaded rectangles: surface ozone season, 1 April to 30 Sept Slopes found for Apr to Sep DOMINO 8.7 ± 1.6 % year 1 In Situ 5.1 ± 1.1 % year 1 Surface data: OMI Overpass Satellite data: Cloud Fraction <

17 OMI NO 2 over Greenbelt, MD Unshaded rectangles: surface ozone season, 1 April to 30 Sept Slopes found for Apr to Sep GSFC In Situ 10.5 ± 3.1 % year ± 1.1 % year 1 Surface data: OMI Overpass Satellite data: Cloud Fraction <

18 Ratios found for Apr to Sep NO 2 DOMINO v2 Weekday/Weekend DOMINO 1.6 ± 0.4 %/year In Situ 1.5 ± 0.2 %/year NO 2 GSFC v2 Weekday/Weekend Surface data: OMI Overpass Satellite data: Cloud Fraction < 0.3 GSFC In Situ 1.5 ± 0.3 %/year 1.5 ± 0.2 %/year 18

19 MOPITT CO over Greenbelt, MD Slopes found for Apr to Sep MOPITT 3.8 ± 0.8 % year 1 In Situ 4.0 ± 0.4 % year 1 Surface data: MOPITT overpass Satellite data: Cloud Fraction <

20 CMAQ used for State Implementation Plans (SIP) to achieve compliance with surface O 3 standard in future 2007 winds & emissions 2007 winds; 2018 emissions Table 1: Scenario 6 Emission Reductions, Year 2018 NO x VOC Marine 31% 13% Off Road 43% 44% Non EGU Pt 8% 1% On Road 58% 39% EGU 43% +17% Area 8% 7% Legend: EGU: Electrical Generating Unit; Pt: Point Source. VOC emissions are assumed to rise in the future from EGUs because of fugitive emissions from the natural gas industry. Example contribution of UMd team to Maryland Department of the Environment (MDE) future SIP effort, under the auspices of the Ozone Transport Commission (12 U.S. eastern states + Wash DC) CMAQ run and analysis by Tim Canty, supported by MDE 20

21 Ozone Distribution CMAQ BASE D-AQ Surface measurements 21

22 NASA DISCOVER-AQ Based on measurements of Weinheimer 22

23 CMAQ Runs 1) CMAQ Baseline 12 x 12 km Grid CB05 mechanism Weather Research & Forecasting model (WRF) meteorology Projected 2012 emissions based on NEI-05 Includes Lightning NO x emissions 2) CMAQ NTR NTR photolysis freq multiplied by 10 because mechanism assumes all organic nitrates photolyze like N propyl nitrate, leading to a very long lifetime for all organic nitrates Reduces the lifetime of NTR (organic nitrates) from ~1 week to ~1 day 3) CMAQ NTR-EMIS NTR photolysis freq multiplied by 10 Mobile emissions reduced by 50%, based on analysis of CMAQ data conducted by Dan Anderson et al. 23

24 Nitrogen Abundance Left: D-AQ; Right: CMAQ BASE } High Ozone Days Based on measurements of Cohen & Weinheimer 24

25 Nitrogen Abundance Left: D-AQ; Right: CMAQ NTR (10 J NTR ) } High Ozone Days Based on measurements of Cohen & Weinheimer 25

26 Nitrogen Abundance Left: D-AQ; Right: CMAQ NTR-EMIS (10 J NTR & 50% Mobil NO x ) } High Ozone Days Based on measurements of Cohen & Weinheimer 26

27 Slope between O x (O 3 +NO 2 ) and NO z (NO y NO x ) serves as an empirical measure of ozone production efficiency (OPE) in an air pollution plume OPE is often plotted as a function of the maximum NO x in a plume 27

28 Ozone Production Efficiency Pressure > 820; r 2 > 0.65 D-AQ CMAQ BASE 28

29 Ozone Production Efficiency Pressure > 820; r 2 > 0.65 D-AQ CMAQ NTR 29

30 Ozone Production Efficiency Pressure > 820; r 2 > 0.65 D-AQ CMAQ NTR-EMIS 30

31 Analysis of ~40 years of surface O Conclusions 3 and NO 2 observations reveals: 1a. Weekends used to have greater chance for a surface O 3 exceedance than weekdays despite lower NO 2 on weekends (VOC limited regime of O 3 production curve) 1b. Since about 2002 the situation has reversed: weekends now have a much smaller probability of exceedance than weekdays (NO x limited region of O 3 production curve) 2a. Satellite column NO 2 generally agrees with surface (ΔNO 2 /NO 2 )/(Δt) to within respective uncertainties, since a. Satellite near surface CO (MOPITT) agrees remarkably well with in situ surface (ΔCO/CO)/(Δt), since OMI NO 2 and DISCOVER AQ NO, NO 2, NO y, etc show CMAQ underestimates NO x /NO y & Ozone Production Efficiency simple changes to CMAQ (increased photolysis of alkyl nitrates; reduction of mobile NO x emissions) move model towards observations, but OPE discrepancy is not fully resolved & other discrepancies persist 31

32 Backup Material to Follow 32

33 EPA NO 2 EPA NO 2 measured via chemiluminescence using a heated (320 C) molybdenum catalyst. Mo + 3NO 2 MoO 3 + 3NO Process has known positive interference from higher oxides of nitrogen. Therefore, measured NO 2 could exceed actual NO 2 and is sometimes called NO 2 * 33

34 Nitrogen Partitioning Left: D-AQ; Right: CMAQ BASE } High Ozone Days 34

35 Nitrogen Partitioning Left: D-AQ; Right: CMAQ NTR (10 J NTR ) } High Ozone Days 35

36 Nitrogen Partitioning Left: D-AQ; Right: CMAQ NTR-EMIS (10 J NTR & 50% Mobil NO x ) } High Ozone Days 36

37 NASA DISCOVER-AQ Correlation between O x (O 3 +NO 2 ) & NO z (NO y NO x ) near downtown Phoenix, June 1998 Slope of correlation defines O 3 Production Efficiency (OPE) NO x limited O 3 Production Efficiency vs maximum NO x in plume VOC limited Kleinman et al., JGR,

38 Ozone Distribution CMAQ BASE D-AQ Surface measurements 38

39 Ozone Distribution CMAQ NTR D-AQ Surface measurements 39

40 Ozone Distribution CMAQ NTR-EMIS D-AQ Surface measurements 40

41 Free Troposphere O 3 Rising 41

42 42

43 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on availability of CO Lower Fifth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 43

44 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fourth of O 3 PDF based on availability of CO Lower Fourth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 44

45 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Third of O 3 PDF based on availability of CO Lower Third of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 45

46 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on availability of CO Lower Fifth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 46

47 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fifth of O 3 PDF based on all O 3 data Lower Fifth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 47

48 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fourth of O 3 PDF based on availability of CO Lower Fourth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 48

49 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Fourth of O 3 PDF based on all O 3 data Lower Fourth of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 49

50 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Third of O 3 PDF based on availability of CO Lower Third of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 50

51 Narrowing of the Surface O 3 Distribution Hourly surface O 3, for BWI T MAX > 90 F Upper Third of O 3 PDF based on all O 3 data Lower Third of CO PDF: i.e., days when air likely to be more reflective of background conditions Upper Fifth of CO PDF 51

52 52

53 NASA DISCOVER-AQ Top: Correlation between O x (O 3 +NO 2 ) & NO z (NO y NO x ) near downtown Phoenix, June 1998 Slope of correlation defines O3 Production Efficiency (OPE) Bottom: OPE vs maximum NO x in plume NOx limited VOC limited Kleinman et al., JGR,

54 NASA DISCOVER-AQ Top: Correlation between O x (O 3 +NO 2 ) & NO z (NO y NO x ) near downtown Phoenix, June 1998 Slope of correlation defines O3 Production Efficiency (OPE) Bottom: OPE vs maximum NO x in plume RED: Pressure > 820 hpa NOx limited VOC limited Based on measurements of Cohen & Weinheimer Kleinman et al., JGR,

55 DISCOVER-AQ RED: Pressure > 820 hpa Top: Correlation between O x (O 3 +NO 2 ) & NO z (NO y NO x ) near downtown Phoenix, June 1998 Slope of correlation defines O3 Production Efficiency (OPE) Bottom: OPE vs maximum NO x in plume NOx limited VOC limited Based on calculations of Choi and Lee Kleinman et al., JGR,

56 NASA DISCOVER-AQ Based on measurements of Cohen & Weinheimer 56

57 NASA DISCOVER-AQ Based on measurements of Weinheimer 57

58 58

59 59

60 Probability of Surface O 3 Exceedance: DC, Md, and Northern Va BWI 60

61 Too small to be seen 61

62 Too small to be seen 62

63 Too small to be seen 63

64 Too small to be seen 64

65 CH 3 C(O)O 2 + NO 2 + M CH 3 C(O)O 2 NO 2 (=PAN) + M IUPAC JPL k 0 = 2.7 x (T/300) -7.1 [N 2 ] k 0 = 9.7 x (T/300) -5.6 k = 1.2 x (T/300) -0.9 k = 9.3 x (T/300) -1.5 k 0 (298) = 2.8 x [N 2 ] k 0 (298) = 1.0 x k (298) = 1.2 x k (298) = 9.4 x Source for both data sets is Bridier et al

66 Forward Reaction Rate 66 66

67 Reverse Reaction Rate 67 67

68 Equilibrium Rate Constant 68 68

69 NASA DISCOVER-AQ 69

70 NASA DISCOVER-AQ 70

71 Surface O 3 : Temporal Transition from Local to Regional 71

72 Surface NO 2 : Steady Improvement Over Time 72