table a1. geographic information (latitude, longitude...

Table A1. Geographic information (latitude, longitude, elevation above sea level) for

CASTNet sites used in our analysis. Sites determined to be regionally-representative are

indicated in bold.

Figure A1. As in Fig. 2, but for the other seven regions. The regionally-representative

sites (mean shown as solid red triangles) are: Northwest - MOR, NCS; California - DEV,

YOS; Plains - BVL, CAD, STK; Great Lakes - DCP, MKG, OXF, SAL; Northeast -

CTH, PSU, WSP; Far Northeast - ASH, HOW; Florida / Gulf - EVE, SUM. Note the

range of magnitudes on the y-axes.

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

25

35

45

55

65

J F M A M J J A S O N D

LAVYOSPINDEVJOTReg. MeanReg. Repr.

California (a)

15

20

25

30

35

40

45


NCSOLYMORGLRReg. MeanReg. Repr.

Northwest(b)

20

30

40

50

60

70


CAD STK VOYALH BVL PRKVIN Reg. Mean Reg. Repr.

Midwest (c)

20

30

40

50

60

70


ANA HOX UVLSAL DCP LYKOXF QAK KEFLRL MKG CDRPAR Reg. Mean Reg. Repr.

Great Lakes

(d)

20

30

40

50

60

70


ABT ARECTH PSUWSP Reg. MeanReg. Repr.

Northeast (e)

20

25

30

35

40

45

50

55


ASH HOW

ACA WST

Reg. Mean Reg. Repr.

Far

Northeast(f)

MDA8 O

3(ppbv)

20

25

30

35

40

45

50

55


EVE SUM

Reg. Mean Reg. Repr.(g)

Florida / Gulf

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

25

35

45

55

65



California (a)

15

20

25

30

35

40

45



Northwest(b)

20

30

40

50

60

70



Midwest (c)

20

30

40

50

60

70



Great Lakes

(d)

20

30

40

50

60

70



Northeast (e)

20

25

30

35

40

45

50

55


ASH HOW

ACA WST


Far

Northeast(f)

MDA8 O

3(ppbv)

20

25

30

35

40

45

50

55


EVE SUM


Florida / Gulf

25

35

45

55

65



California (a)

25

35

45

55

65



California

25

35

45

55

65



California (a)

15

20

25

30

35

40

45



Northwest(b)

15

20

25

30

35

40

45



Northwest(b)

20

30

40

50

60

70



Midwest (c)

20

30

40

50

60

70



Great Lakes

(d)

20

30

40

50

60

70



Great Lakes

(d)

20

30

40

50

60

70



Northeast (e)

20

30

40

50

60

70



Northeast (e)

20

25

30

35

40

45

50

55


ASH HOW

ACA WST


Far

Northeast(f)

20

25

30

35

40

45

50

55


ASH HOW

ACA WST


Far

Northeast(f)

MDA8 O

3(ppbv)

20

25

30

35

40

45

50

55


EVE SUM


Florida / Gulf

MDA8 O

3(ppbv)

20

25

30

35

40

45

50

55


EVE SUM


Florida / Gulf

Figure A2. As in Fig. 3, but for the other seven regions.

30

40

50

60

70

80


1996

1997

1998

1999

2000

2001

2002

2003

2004

Mean

California10

15

20

25

30

35

40

45


1996

1997

1998

1999

2000

2001

2002

2003

2004

Mean

Northwest

(a) (b)

15

25

35

45

55

65

75

85


19881989199019911992199319941995199619971998199920002001200220032004Mean

Great Lakes

(d)

15

25

35

45

55

65

75


19881989199019911992199319941995199619971998199920002001200220032004Mean

20

25

30

35

40

45

50

55

60

65


1989199019911992199319941995199619971998199920002001200220032004Mean

Midwest

(c)

(e)

Northeast

15

20

25

30

35

40

45

50


199319941995199619971998199920002001200220032004Mean

(f)

Far Northeast

20

25

30

35

40

45

50

55

60


1998

1999

2000

2001

2002

2003

2004

MeanMDA8 O

3(ppbv)

Florida / Gulf

(g)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

30

40

50

60

70

80


1996

1997

1998

1999

2000

2001

2002

2003

2004

Mean

California10

15

20

25

30

35

40

45


1996

1997

1998

1999

2000

2001

2002

2003

2004

Mean

Northwest

(a) (b)

15

25

35

45

55

65

75

85


19881989199019911992199319941995199619971998199920002001200220032004Mean

Great Lakes

(d)

15

25

35

45

55

65

75


19881989199019911992199319941995199619971998199920002001200220032004Mean

20

25

30

35

40

45

50

55

60

65


1989199019911992199319941995199619971998199920002001200220032004Mean

Midwest

(c)

20

25

30

35

40

45

50

55

60

65


1989199019911992199319941995199619971998199920002001200220032004Mean

Midwest

(c)

(e)

Northeast

15

20

25

30

35

40

45

50


199319941995199619971998199920002001200220032004Mean

(f)

Far Northeast

20

25

30

35

40

45

50

55

60


1998

1999

2000

2001

2002

2003

2004

MeanMDA8 O

3(ppbv)

Florida / Gulf

(g)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

Table A2. Details of the global models used in our analysis, including emissions

inventories and meteorological fields employed for the HTAP simulations. Further

description of model characteristics is available at: http://www.mi.uni-hamburg.de/List-

classification-and-detail-view-of-model-entr.567.0.html. Adapted from Fiore et al.

[2009].

ModelResolution

(lon x lat x layers)Institution Model contact

Anthropogenic emission

inventory for O3

precursors

Driving

meteorology

(year 2001)

CAMCHEM-

3311m13# 2.5° x 2° x 30 NCAR, USA Peter Hess

POET for 1997a; CO fossil

fuel and biofuel from a

MOPITT inversionb

NCEP

ECHAM5-

HAMMOZ-v212.81° x 2.81° x 21

EPFL,

SwitzerlandGerd Folberth RETRO

ECMWF ERA-

40

EMEP-rv26#

(NH only)1° x 1° x 20 EMEP, Norway

Jan Eiof Jonson,

Peter Wind

IER / Uni-Stuttgart, based

on EDGAR2000; EMEP

ECMWF ERA-

40

FRSGC/UCI

v01# 2.81° x 2.81° x 37

Lancaster

University, UKOliver Wild ACCENT/AR4

cECMWF IFS

d

GEMAQ-EC 2° x 2° x 20Environment

CanadaSunling Gong

AURAMS (regional

Canadian, US and Mexico);

EDGAR elsewhere

Canadian

Meteorological

Centre (CMC)

GEMAQ-v1p0# 4° x 4° x 28

York

University,

Canada

Alexandru Lupu EDGAR v2 CMC

GEOS-Chem

v07# 2.5° x 2° x 30

Harvard

University,

USA

Rokjin Park Bey et al., 2001e NASA GEOS-4

GEOS-Chem

v07-res4x55° x 4° x 30 CIEMAT, Spain

Marta Garcia

Vivanco

EMEP emissions

EPA/NEI99 inventoryNASA GEOS-4

GISS-PUCCNI-

modelE# 5° x 4° x 23

NASA GISS,

USADrew Shindell

ACCENT / AR4, with EA

emissions of CO and NOx

times 1.66

NCEP, via linear

relaxation

GMI-v02f# 2.5° x 2° x 42

NASA GSFC,

USABryan Duncan

Harvard's merged inventory

(NEI99, BRAVO, Streets,

EMEP)

NASA GEOS-4

LMDz3-INCA1# 3.75° x 2.5° x 19 LSCE, France Sophie Szopa RETRO

ECMWF ERA-

40

LLNL-IMPACT-

T5a# 2.5° x 2° x 48 LLNL, USA

Cynthia Atherton,

Daniel BergmannPOET

NASA GEOS-4-

ceres

MOZART-

GFDL-v2# 1.88° x 1.88° x 28 GFDL, USA Arlene Fiore EDGAR v2 NCEP

MOZECH-v16# 2.81 x 2.81 x 31

FZ Jülich,

Germany

Martin Schultz,

Sabine SchröderRETRO

ECMWF ERA-

40

Oslo CTM2 2.81° x 2.81° x 40University of

Oslo, NorwayMichael Gauss EDGAR v3.2 ECMWF - IFS

TM5-JRC-cy2-

ipcc-v1# 1° x 1° x 25 JRC, Italy

Frank Dentener,

Elina MarmerACCENT / AR4 ECMWF

# - Model used in NOx+CO+VOC+aerosol emission perturbation simulations (all 16 used for "base-case" comparisons)

a - Granier, C. et al. (2004), Present and future surface emissions of atmospheric compounds, European

Commission report EVK 2199900011. (Available at http:// http://www.aero.jussieu.fr/projet/ACCENT/POET.php) b - Pétron, G., C. Granier, B. Khattatov, V. Yudin, J. Lamarque, L. Emmons, J. Gille, and D. P. Edwards

(2004), Monthly CO surface sources inventory based on the 2000 - 2001 MOPITT satellite data, Geophys.

Res. Lett., 31, L21107, doi:10.1029/2004GL020560. c - Bond, T.C. et al. (2004), A technology-based global inventory of black and organic carbon emissions

from combustion, J. Geophys. Res., 109, D14203, doi:10.1029/2003JD003697. d - van der Werf, G.R., J.T. Randerson, L. Giglio, G.J. Collatz, P.S. Kasibhatla, and A.F. Arellano, Jr.

(2006), Interannual variability in global biomass burning emissions from1997 to 2004, Atmos. Chem.

Physics, 6, 3423-3441. e - based on EDGAR v3.2, see Stevenson et al. [2006]

NA EU

SAEANA EU

SAEA

Figure A3. Colored boxes represent the four source regions used in the HTAP emissions

reductions simulations: NA - North America, EU - Europe, SA - South Asia, EA - East

Asia [adapted from TF HTAP, 2007].

Figure A4. Evaluation of multi-model vs.observed values of MBDA O3 for the regions

not shown in Fig. 4. Individual models are shown with open circles; multi-model mean

as solid black squares and observations as solid red triangles.

15

25

35

45

55

65

75

85

95


10

20

30

40

50

60


(b)

Northwest

10

20

30

40

50

60

70

80

90

100


(c)

Midwest

10

20

30

40

50

60

70

80

90

100

110


(d)

Great Lakes

0

20

40

60

80

100


(e)

Northeast10

20

30

40

50

60

70


(f)

Far Northeast

15

25

35

45

55

65

75


(g)

Florida / Gulf

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

CAMCHEM ECHAM5 EMEP FRSGCUCI GEMAQ-EC GEMAQ-v1p0 GEOSChem-v07 GEOSChem-v45 GISS-PUCCINI GMI INCA-vSSz LLNL-IMPACT MOZARTGFDL MOZECH OsloCTM2 TM5-JRC OBS Multi-model mean

(a)

California

15

25

35

45

55

65

75

85

95


10

20

30

40

50

60


(b)

Northwest10

20

30

40

50

60


(b)

Northwest

10

20

30

40

50

60

70

80

90

100


(c)

Midwest

10

20

30

40

50

60

70

80

90

100


(c)

Midwest

10

20

30

40

50

60

70

80

90

100

110


(d)

Great Lakes

10

20

30

40

50

60

70

80

90

100

110


(d)

Great Lakes

0

20

40

60

80

100


(e)

Northeast0

20

40

60

80

100


(e)

Northeast0

20

40

60

80

100


(e)

Northeast10

20

30

40

50

60

70


(f)

Far Northeast10

20

30

40

50

60

70


10

20

30

40

50

60

70


(f)

Far Northeast

15

25

35

45

55

65

75


(g)

Florida / Gulf15

25

35

45

55

65

75


(g)

Florida / Gulf

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

MDA8 O

3(ppbv)

CAMCHEM ECHAM5 EMEP FRSGCUCI GEMAQ-EC GEMAQ-v1p0 GEOSChem-v07 GEOSChem-v45 GISS-PUCCINI GMI INCA-vSSz LLNL-IMPACT MOZARTGFDL MOZECH OsloCTM2 TM5-JRC OBS Multi-model mean

(a)

California

Figure A5. Daily MDA8 O3 from observations (red line), multi-model ensemble mean

(black line) and 1σ of ensemble mean (gray shading) for spring (MAM), summer (JJA)

and autumn (SON) in the seven regions not shown in Fig. 5. Note the range of

magnitudes on the y-axes.

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

MDA8 O

3(ppbv)

California Region

20

25

30

35

40

45

50

55

60

M A M

r2 = 0.36

Northwest Region

10

20

30

40

50

60

70

80

J J A

r2 = 0.64

10

20

30

40

50

60

70

S O N

r2 = 0.22

MDA8 O

3(ppbv)

+/- 1SD of multi-model mean Multi-model mean Obs

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

MDA8 O

3(ppbv)

California Region

20

25

30

35

40

45

50

55

60

M A M

r2 = 0.36

Northwest Region

10

20

30

40

50

60

70

80

J J A

r2 = 0.64

10

20

30

40

50

60

70

S O N

r2 = 0.22

MDA8 O

3(ppbv)

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

MDA8 O

3(ppbv)

California Region

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

MDA8 O

3(ppbv)

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

25

35

45

55

65

75

85

M A M

r2 = 0.46

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.43

20

30

40

50

60

70

80

90

100

S O N

r2 = 0.74

MDA8 O

3(ppbv)

California Region

20

25

30

35

40

45

50

55

60

M A M

r2 = 0.36

Northwest Region

10

20

30

40

50

60

70

80

J J A

r2 = 0.64

10

20

30

40

50

60

70

S O N

r2 = 0.22

20

25

30

35

40

45

50

55

60

M A M

r2 = 0.36

Northwest Region

10

20

30

40

50

60

70

80

J J A

r2 = 0.64

10

20

30

40

50

60

70

S O N

r2 = 0.22

MDA8 O

3(ppbv)


Figure A5. (cont’d)

0

20

40

60

80

S O N

r2 = 0.70

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.45

20

30

40

50

60

70

80

M A M

r2 = 0.60

Midwest Region

MDA8 O

3(ppbv)

20

30

40

50

60

70

80

90

M A M

r2 = 0.70

30

50

70

90

110

J J A

r2 = 0.46

10

30

50

70

90

S O N

r2 = 0.75


MDA8 O

3(ppbv)

Great Lakes Region

0

20

40

60

80

S O N

r2 = 0.70

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.45

20

30

40

50

60

70

80

M A M

r2 = 0.60

Midwest Region

MDA8 O

3(ppbv)

0

20

40

60

80

S O N

r2 = 0.70

20

30

40

50

60

70

80

90

100

J J A

r2 = 0.45

20

30

40

50

60

70

80

M A M

r2 = 0.60

Midwest Region

MDA8 O

3(ppbv)

20

30

40

50

60

70

80

90

M A M

r2 = 0.70

30

50

70

90

110

J J A

r2 = 0.46

10

30

50

70

90

S O N

r2 = 0.75

20

30

40

50

60

70

80

90

M A M

r2 = 0.70

30

50

70

90

110

J J A

r2 = 0.46

10

30

50

70

90

S O N

r2 = 0.75


MDA8 O

3(ppbv)

Great Lakes Region


0

20

40

60

80

100

S O N

r2 = 0.80

15

25

35

45

55

65

75

85

95

M A M

r2 = 0.59

Northeast Region

30

50

70

90

110

J J A

r2 = 0.61M

DA8 O

3(ppbv)

10

30

50

70

90

S O N

r2 = 0.68

10

30

50

70

90

J J A

r2 = 0.48


20

30

40

50

60

70

80

M A M

r2 = 0.54

MDA8 O

3(ppbv)

Far Northeast Region

0

20

40

60

80

100

S O N

r2 = 0.80

15

25

35

45

55

65

75

85

95

M A M

r2 = 0.59

Northeast Region

30

50

70

90

110

J J A

r2 = 0.61M

DA8 O

3(ppbv)

0

20

40

60

80

100

S O N

r2 = 0.80

15

25

35

45

55

65

75

85

95

M A M

r2 = 0.59

Northeast Region

30

50

70

90

110

J J A

r2 = 0.61M

DA8 O

3(ppbv)

10

30

50

70

90

S O N

r2 = 0.68

10

30

50

70

90

J J A

r2 = 0.48


20

30

40

50

60

70

80

M A M

r2 = 0.54

MDA8 O

3(ppbv)



10

20

30

40

50

60

70

80

90

M A M

r2 = 0.70

Florida / Gulf Region

0

20

40

60

80

100

J J A

r2 = 0.71

10

20

30

40

50

60

70

80

90

S O N

r2 = 0.37

MDA8 O

3(ppbv)


10

20

30

40

50

60

70

80

90

M A M

r2 = 0.70


0

20

40

60

80

100

J J A

r2 = 0.71

10

20

30

40

50

60

70

80

90

S O N

r2 = 0.37

MDA8 O

3(ppbv)


Figure A6. Number of days for each MDA8 O3 bin (right-axis) from the multi-model

ensemble (black squares) and observations (red triangles) and the sum of the responses of

MDA8 O3 to 20% reductions in anthropogenic O3-precursor emissions (NOx + CO +

NMVOC + aerosols) in the three foreign source regions (left-axis; green columns with

error bars representing 1σ of the multi-model mean) in the seven regions not shown in

Fig. 6, binned by simulated MDA8 O3, for spring (MAM), summer (JJA) and autumn

(SON). Note the range of magnitudes on the y-axes.

MDA8 O3 (ppbv)MDA8 O3 (ppbv)Foreign influence # Days_Multi-model mean # Days_Obs

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96Decline in MDA8 O

3(ppbv)

# Days

Northwest Region

MAM

JJA

SON

MDA8 O3 (ppbv)MDA8 O3 (ppbv)Foreign influence # Days_Multi-model mean # Days_Obs

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96Decline in MDA8 O

3(ppbv)

# Days

Northwest Region

MAM

JJA

SON

MDA8 O3 (ppbv)Foreign influence # Days_Multi-model mean # Days_Obs

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96Decline in MDA8 O

3(ppbv)

# Days

Northwest Region



0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

11

22

33

44

55

66

California Region

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96Decline in MDA8 O

3(ppbv)

# Days

Northwest Region

MAM

JJA

SON



0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

0.0

0.1

0.2

0.3

0.4

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

Midwest Region Great Lakes Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

MAM MAM

JJA JJA

SON SON


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

0.0

0.1

0.2

0.3

0.4

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days



0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

0.0

0.1

0.2

0.3

0.4

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

Midwest Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

0.0

0.1

0.2

0.3

0.4

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

MDA8 O3 (ppbv)

Great Lakes Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

0.0

0.1

0.2

0.3

0.4

0.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

MAM MAM

JJA JJA

SON SON



0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

Northeast Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

MDA8 O3 (ppbv) MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

# Days

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

Decline in MDA8 O

3(ppbv)


MAM MAM

JJA JJA

SON SON


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

Northeast Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48


Decline in MDA8 O

3(ppbv)

# Days

# Days

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

Decline in MDA8 O

3(ppbv)




0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

4

8

12

16

20

24

28

32

36

40

Northeast Region

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48


Decline in MDA8 O

3(ppbv)

# Days

# Days

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

Decline in MDA8 O

3(ppbv)


MAM MAM

JJA JJA

SON SON



0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45


0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

MAM

JJA

SON


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45


0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days



0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45


0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

MDA8 O3 (ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

MAM

JJA

SON

Figure A7. As in Fig. 7, but for the other seven regions.

Bias in m

ulti-model mean vs. obs(ppbv)

Bias in m


Modeled foreign influence,

SA + EA + EU (ppbv)

Modeled NA influence (ppbv)

-10

-5

0

5

10

15

20

0.0 0.3 0.6 0.9 1.2 1.5

(b)

Northwest

r2 = 0.002

-15

-10

-5

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0

Plains

(c) r2 = 0.376

-15

-10

-5

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0

Plains

(c) r2 = 0.376

-20

-15

-10

-5

0

5

10

15

0.0 0.3 0.6 0.9 1.2 1.5

(a)

California

r2 = 0.093

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

(d)

-30

-20

-10

0

10

20

30

0 1 2 3 4 5 6

(c)

California

r2 = 0.211

(e)

-20

-10

0

10

20

30

40

0 1 2 3 4 5

(d)

Northwest

r2 = 0.000

(f)

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018(g)

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

(h)

MidwestMidwest

Bias in m


Bias in m



SA + EA + EU (ppbv)


-10

-5

0

5

10

15

20

0.0 0.3 0.6 0.9 1.2 1.5

(b)

Northwest

r2 = 0.002-10

-5

0

5

10

15

20

0.0 0.3 0.6 0.9 1.2 1.5

(b)

Northwest

r2 = 0.002

-15

-10

-5

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0

Plains

(c) r2 = 0.376

-15

-10

-5

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0

Plains

(c) r2 = 0.376

-20

-15

-10

-5

0

5

10

15

0.0 0.3 0.6 0.9 1.2 1.5

(a)

California

r2 = 0.093

-20

-15

-10

-5

0

5

10

15

0.0 0.3 0.6 0.9 1.2 1.5

(a)

California

r2 = 0.093

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

(d)

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

-15

-10

-5

0

5

10

15

20

25

0.0 0.3 0.6 0.9 1.2

Great Lakes

(b)r2 = 0.332

(d)

-30

-20

-10

0

10

20

30

0 1 2 3 4 5 6

(c)

California

r2 = 0.211

(e)

-30

-20

-10

0

10

20

30

0 1 2 3 4 5 6

(c)

California

r2 = 0.211-30

-20

-10

0

10

20

30

0 1 2 3 4 5 6

(c)

California

r2 = 0.211

(e)

-20

-10

0

10

20

30

40

0 1 2 3 4 5

(d)

Northwest

r2 = 0.000

(f)

-20

-10

0

10

20

30

40

0 1 2 3 4 5

(d)

Northwest

r2 = 0.000-20

-10

0

10

20

30

40

0 1 2 3 4 5

(d)

Northwest

r2 = 0.000

(f)

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018(g)

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018

-10

0

10

20

30

40

0 1 2 3 4 5 6

Plains

(c) r2 = 0.018(g)

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

(h)

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

-20

-10

0

10

20

30

40

0 1 2 3 4 5 6 7

Great Lakes

(d)

r2 = 0.037

(h)

MidwestMidwest


-25

-20

-15

-10

-5

0

5

10

15

20

0.0 0.5 1.0 1.5 2.0

(b)

Far Northeast

r2 = 0.055

Bias in m


Bias in m



SA + EA + EU (ppbv)


-20

-10

0

10

20

30

40

0.0 0.3 0.6 0.9 1.2

(a)

Northeast

r2 = 0.298

-5

0

5

10

15

20

25

30

0.0 0.3 0.6 0.9 1.2

(c) Florida / Gulf

r2 = 0.301

-5

0

5

10

15

20

25

30

0.0 0.3 0.6 0.9 1.2

(c) Florida / Gulf

r2 = 0.301

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6

(f)

Florida / Gulf

r2 = 0.001

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6

(f)

Florida / Gulf

r2 = 0.001

-10

0

10

20

30

40

50

0 1 2 3 4 5 6 7

Northeast

r2 = 0.008(d)

-20

-10

0

10

20

30

40

50

0 1 2 3 4 5 6

Far Northeast r2 = 0.266

(e)

-25

-20

-15

-10

-5

0

5

10

15

20

0.0 0.5 1.0 1.5 2.0

(b)

Far Northeast

r2 = 0.055

-25

-20

-15

-10

-5

0

5

10

15

20

0.0 0.5 1.0 1.5 2.0

(b)

Far Northeast

r2 = 0.055

Bias in m


Bias in m



SA + EA + EU (ppbv)


-20

-10

0

10

20

30

40

0.0 0.3 0.6 0.9 1.2

(a)

Northeast

r2 = 0.298

-20

-10

0

10

20

30

40

0.0 0.3 0.6 0.9 1.2

(a)

Northeast

r2 = 0.298

-5

0

5

10

15

20

25

30

0.0 0.3 0.6 0.9 1.2

(c) Florida / Gulf

r2 = 0.301

-5

0

5

10

15

20

25

30

0.0 0.3 0.6 0.9 1.2

(c) Florida / Gulf

r2 = 0.301

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6

(f)

Florida / Gulf

r2 = 0.001

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6

(f)

Florida / Gulf

r2 = 0.001

-10

0

10

20

30

40

50

0 1 2 3 4 5 6 7

Northeast

r2 = 0.008(d)

-10

0

10

20

30

40

50

0 1 2 3 4 5 6 7

Northeast

r2 = 0.008(d)

-20

-10

0

10

20

30

40

50

0 1 2 3 4 5 6


(e)

-20

-10

0

10

20

30

40

50

0 1 2 3 4 5 6


(e)

Figure A8. Multi-model mean (black line) and 1σ of the ensemble mean (gray shading)

in the day-to-day variability of the response of MDA8 O3 to a 20% reduction in

anthropogenic O3−precursor emissions (NOx + CO + NMVOC + aerosols) in the three

foreign sources regions (Fig. A3) for the 7 regions not shown in Fig. 8. Note the range of

magnitudes on the y-axes.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

S O N

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

J J A

0.0

0.3

0.6

0.9

1.2

1.5

1.8

M A M

California Region

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

M A M

Northwest Region

0.0

0.2

0.4

0.6

0.8

1.0

1.2

J J A

0.0

0.2

0.4

0.6

0.8

1.0

1.2

S O N

Decline in M

DA8 O

3(ppbv)

Decline in M

DA8 O

3(ppbv)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

S O N

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

J J A

0.0

0.3

0.6

0.9

1.2

1.5

1.8

M A M

California Region

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

M A M

Northwest Region

0.0

0.2

0.4

0.6

0.8

1.0

1.2

J J A

0.0

0.2

0.4

0.6

0.8

1.0

1.2

S O N

Decline in M

DA8 O

3(ppbv)

Decline in M

DA8 O

3(ppbv)


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

J J A

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

S O N

-0.3

-0.1

0.1

0.3

0.5

0.7

J J A

0.0

0.2

0.4

0.6

0.8

1.0

1.2

M A M

Midwest Region

Decline in MDA8 O

3(ppbv)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

M A M

Great Lakes Region

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

S O N

Decline in M

DA8 O

3(ppbv)

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

J J A

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

S O N

-0.3

-0.1

0.1

0.3

0.5

0.7

J J A

0.0

0.2

0.4

0.6

0.8

1.0

1.2

M A M

Midwest Region

Decline in MDA8 O

3(ppbv)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

M A M

Great Lakes Region

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

S O N

Decline in M

DA8 O

3(ppbv)


-0.3

0.0

0.3

0.6

0.9

1.2

1.5

M A M

-0.5

0.0

0.5

1.0

1.5

J J A

0.0

0.3

0.6

0.9

S O N

Decline in MDA8 O

3(ppbv)

Northeast Region

Decline in MDA8 O

3(ppbv)

0.0

0.5

1.0

1.5

2.0

2.5

M A M


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

J J A

0.0

0.2

0.4

0.6

0.8

1.0

S O N

-0.3

0.0

0.3

0.6

0.9

1.2

1.5

M A M

-0.5

0.0

0.5

1.0

1.5

J J A

0.0

0.3

0.6

0.9

S O N

Decline in MDA8 O

3(ppbv)

Northeast Region

Decline in MDA8 O

3(ppbv)

0.0

0.5

1.0

1.5

2.0

2.5

M A M


-0.2

0.0

0.2

0.4

0.6

0.8

1.0

J J A

0.0

0.2

0.4

0.6

0.8

1.0

S O N


0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

M A M


Decline in M

DA8 O

3(ppbv)

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

J J A

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

S O N

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

M A M


Decline in M

DA8 O

3(ppbv)

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

J J A

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

S O N

Figure A9. As in Fig. A6, but for a 20% emissions reduction of anthropogenic O3-

precursors (NOx + CO + NMVOC + aerosols) in the North American source region

(shown in Fig. A3). Note the range of magnitudes on the y-axes.

MDA8 O3 (ppbv)

NA influence # Days_Multi-model mean # Days_Obs

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

California Region

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

Decline in MDA8 O

3(ppbv)

Decline in MDA8 O

3(ppbv)

# Days

# Days

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

Northwest Region

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45

54

63

72

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96

MDA8 O3 (ppbv)

MAM MAM

JJAJJA

SON SON

MDA8 O3 (ppbv)


0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

California Region

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

40

45

Decline in MDA8 O

3(ppbv)

Decline in MDA8 O

3(ppbv)

# Days

# Days

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

60

70

Northwest Region

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45

54

63

72

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

84

96

MDA8 O3 (ppbv)

MAM MAM

JJAJJA

SON SON



-1

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

-0.5

0.5

1.5

2.5

3.5

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

Midwest Region


Decline in M

DA8 O

3(ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

# Days

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

Great Lakes Region

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

MAM MAM

JJA JJA

SON SON


-1

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

-0.5

0.5

1.5

2.5

3.5

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

Midwest Region


Decline in M

DA8 O

3(ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

# Days

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

Great Lakes Region

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42


-1

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

48

-0.5

0.5

1.5

2.5

3.5

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

8

16

24

32

40

Midwest Region


Decline in M

DA8 O

3(ppbv)

Decline in M

DA8 O

3(ppbv)

# Days

# Days

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

5

10

15

20

25

30

35

Great Lakes Region

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

-2

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

MAM MAM

JJA JJA

SON SON



-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

Northeast Region

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

Decline in M

DA8 O

3(ppbv)


# Days

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

MDA8 O3 (ppbv)

MAM MAM

JJAJJA

SON SON


-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

Northeast Region

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

Decline in M

DA8 O

3(ppbv)


# Days

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

MDA8 O3 (ppbv)


-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

Northeast Region

-2

-1

0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

6

12

18

24

30

36

42

48

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0-35 35-45 45-55 55-65 65-75 75+

0

7

14

21

28

35

42

49

56

63

Decline in M

DA8 O

3(ppbv)


# Days

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

10

20

30

40

50

-1

0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

MDA8 O3 (ppbv)

MAM MAM

JJAJJA

SON SON



0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45


0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

13

26

39

52

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON


0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45


0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

13

26

39

52

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days


0

1

2

3

4

5

0-35 35-45 45-55 55-65 65-75 75+

0

9

18

27

36

45


0

1

2

3

4

5

6

0-35 35-45 45-55 55-65 65-75 75+

0

12

24

36

48

60

72

0

1

2

3

4

0-35 35-45 45-55 55-65 65-75 75+

0

13

26

39

52

MDA8 O3 (ppbv)

Decline in MDA8 O

3(ppbv)

# Days

MAM

JJA

SON

Figure A10. As in Fig. A8, but for a 20% emissions reduction of anthropogenic O3-

precursors (NOx + CO + NMVOC + aerosols) in the North American source region

(shown in Fig. A3). Note the range of magnitudes on the y-axes.

0

1

2

3

4

5

M A M

0

1

2

3

4

5

6

7

J J A

-1

0

1

2

3

4

5

6

S O N

-1

0

1

2

3

4

M A M

-1

0

1

2

3

4

5

S O N

0

1

2

3

4

5

6

J J A

California Region Northwest Region

Decline in MDA8 O

3(ppbv)

Decline in MDA8 O

3(ppbv)

0

1

2

3

4

5

M A M

0

1

2

3

4

5

6

7

J J A

-1

0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

M A M

0

1

2

3

4

5

6

7

J J A

-1

0

1

2

3

4

5

6

S O N

-1

0

1

2

3

4

M A M

-1

0

1

2

3

4

5

S O N

0

1

2

3

4

5

6

J J A

-1

0

1

2

3

4

M A M

-1

0

1

2

3

4

5

S O N

0

1

2

3

4

5

6

J J A

California Region Northwest Region

Decline in MDA8 O

3(ppbv)

Decline in MDA8 O

3(ppbv)


-2

-1

0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

6

7

8

J J A

-2

-1

0

1

2

3

4

5

M A M

Midwest Region

Decline in M

DA8 O

3(ppbv)

-5

-3

-1

1

3

5

7

M A M

Great Lakes Region

0

1

2

3

4

5

6

7

8

9

J J A

-4

-2

0

2

4

6

S O N

Decline in MDA8 O

3(ppbv)

-2

-1

0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

6

7

8

J J A

-2

-1

0

1

2

3

4

5

M A M

Midwest Region

Decline in M

DA8 O

3(ppbv)

-2

-1

0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

6

7

8

J J A

-2

-1

0

1

2

3

4

5

M A M

Midwest Region

Decline in M

DA8 O

3(ppbv)

-5

-3

-1

1

3

5

7

M A M

Great Lakes Region

0

1

2

3

4

5

6

7

8

9

J J A

-4

-2

0

2

4

6

S O N

Decline in MDA8 O

3(ppbv)


Decline in MDA8 O

3(ppbv)

-3

-1

1

3

5

7

M A M

0

2

4

6

8

J J A

-3

-1

1

3

5

7

S O N

Decline in MDA8 O

3(ppbv)

Northeast Region

-1

0

1

2

3

4

5

6

M A M


0

1

2

3

4

5

6

7

J J A

-2

-1

0

1

2

3

4

5

6

S O N

Decline in MDA8 O

3(ppbv)

-3

-1

1

3

5

7

M A M

0

2

4

6

8

J J A

-3

-1

1

3

5

7

S O N

Decline in MDA8 O

3(ppbv)

Northeast Region

-3

-1

1

3

5

7

M A M

0

2

4

6

8

J J A

-3

-1

1

3

5

7

S O N

Decline in MDA8 O

3(ppbv)

Northeast Region

-1

0

1

2

3

4

5

6

M A M


0

1

2

3

4

5

6

7

J J A

-2

-1

0

1

2

3

4

5

6

S O N


0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

6

M A M


0

1

2

3

4

5

6

7

J J A

Decline in M

DA8 O

3(ppbv)

0

1

2

3

4

5

6

S O N

0

1

2

3

4

5

6

M A M


0

1

2

3

4

5

6

7

J J A

Decline in M

DA8 O

3(ppbv)

table a1. geographic information (latitude, longitude...

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