1. June 11, 2015 Maryland Smoke &
8-Hour Ozone Exceedance Event
Joel Dreessen
Meteorologist, Maryland Department
of the Environment
12/15/2015

2. Smoke covers the sky near La Ronge, Sask. on Sunday,
June 7, 2015. This picture was taken by Jamie Chester in
the middle of the afternoon.
Image Source: paNOW
Image Source: Lac La Ronge Indian Board;
Sunday, June 7, 2015, 9:47PM
Image Source: Global News
Image Source: Global News
25 new fires on June 6,
2015 with 12 still out of
control on June 8th!

3. Image Source: NASA Earth
Observatory; ARLHYSPLIT; SSEC
of UWM, MODIS
Ozone Mapping Profiler Suite (OMPS) on the Suomi NPP satellite.
Smoke Plume Trek
June 7 June 8 June 9
aerosols

5. Image Source: NESDIS; IDEA
GOES Aerosol/
Smoke Product

7. Smoke just lingers over the
Mid-Atlantic

8. 0.0 0.2 0.4 0.6 0.8 1.0
AOD
c) June 11, 2015a) June 9, 2015 b) June 10, 2015
- Howard University Beltsville

9. June 9, 2015
(µg/m3)
June 10, 2015
(µg/m3)
Ozone
june9
<VALUE>
<50
<50
55 - 60
60 - 65
65 - 70
70 - 75
>75
ppb
June 10, 2015June 9, 2015
Ozone
june9
<VALUE>
<50
<50
55 - 60
60 - 65
65 - 70
70 - 75
>75
ppb
Ozone
june9
<VALUE>
<50
<50
55 - 60
60 - 65
65 - 70
70 - 75
>75
June 11, 2015
ppb
Maximum 8-Hour Ozone
24-Hour Average PM2.5
June 11, 2015
(µg/m3)
Smoke Plume Progression
-PM2.5 and Ozone both line up well with the smoke plume path
-Delay in Ozone compared to smoke onset
-June 11, 2015 was the worst day of the event - everywhere

10. Why the ozone/PM disparity?
What role did the smoke play?
• Ozone exceedance in Maryland not until June 11,
though smoke arrived on evening of June 9, 2015
• Did smoke aid in ozone production?
• If smoke did
aid in ozone
production,
how?
*Circle color does not
represent air quality
index level
*

11. Maryland Summary
• UNHEALTHY AQI at Fair Hill (northeast MD)
• USG at
– All 3 DC monitors
– 6 Maryland monitors
– 70% of network >70ppb
• Event centered along
I-95 corridor
• Worst air quality since
6/29/2012 (Derecho)
Aldino
Davidsonville
Edgewood
Essex
Furley
Padonia
SouthCarroll
Calvert
PGEquest.Ctr.
FrederickAirport
HowardU.
Beltsville*
Rockville
So.Maryland
FairHill
BlackwaterNWR*
Millington
HornPoint
Hagerstown
PineyRun
2014 Design Value 73 74 75 72 64 72 69 73 76 70 70 75 68 71 77 70 74 73 67 68
06/11/2015 83 81 88 86 83 100
No exceedance with
Bay Breeze

12. 5pm EDT
Wide-spread
haze reported,
but Good O3 AQ;
no exceedances
•Subsidence behind the cold front and associated with high pressure allowed smoke to
subside to the surface
•Indiana, as early as 6/9 reported haze, yet ended the day with Good Ozone AQ, but
UPPER Moderate AQ for PM 2.5 and Moderate AQ for PM 10
•Smoke was reaching the surface but did not create an immediate Ozone response
Gray: general area of
subsidence
(sinking motion)

13. 10 mi
Smoke at
the surface
Smoke descended
at least 3.5km to
reach the surface
SMOKE
LIDAR image courtesy Dr. Ruben Delgado, UMBC

14. HUB - Ecotech Aurora 1000
nephelometer (525 nm)
UMBC - Aerodyne CAPS
PMex Extinction monitor
(532nm)
- UMBC aerosol Lidar
Observation Period
PM2.5 – FEM MetOne Beta
Attenuation Monitors
(BAM) –1020
UV – Eppley Lab Total UV
Radiometer (295-385nm)
Increase in PM2.5 behind
the cold front (doubling)
Scattering Coefficient and Extinction [Mm-1]
PM2.5 Surface Concentration [µg m-3]
Essex Ultra-Violet Radiation [W m-2]
14%
Reduction
9%
Reduction
56 W m-2
Increase in surface
light extinction –
consistent with more
PBL smoke subsidence
Smoke increased during
the 10th, peaked on 11th

15. June 11, 2015
Ozone
june9
<VALUE>
<50
<50
55 - 60
60 - 65
65 - 70
70 - 75
>75
June 11, 2015
ppb
June 11, 2015
June 11, 2015
(µg/m3)
(µg/m3)
24-Hour Average PM2.5
Potassium Ion (K+)
Organic Carbon
Surface Smoke Tracers
FRM and FEM Particle Speciation
June 11, 2015 (EPA regions 1-5)
•Potassium Ions
•Organic Carbon
•Southwest to Northeast axis of ~30 µg m-3
PM2.5 from West Virginia to New Jersey
Maximum 8-hour Ozone

16. June 11, 2015 Maryland
Meteorology
• Westerly 500m trajectories
• Weak, southwest surface
transport along I-95 corridor
• Weak Appalachian Lee Trough
along I-95 corridor
• Bay Breeze at Essex and
Edgewood (did not exceed)
• BWI airport:
6/9 6/10 6/11 6/12
Tmax (°F) 84 84 93 94
Avg WS
(kts)
9.4 3.5 3.9 6.2
Source: NOAA NWS, ARL
Significant temperature difference;
2°F from record high on 6/11

17. The Role of the Smoke
• Greater concentrations of reactive VOCs within the smoke amplified ozone reactions
• The NOx heavy I-95 and Ohio River Valley corridor could then utilize the VOCs in
ozone production
• VOC data from MDE supports this hypothesis but with a significant delay in ozone
response; VOCs maximized on June 11, 2015
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
6/9/2015 6/10/2015 6/11/2015 6/12/2015
Sum PAMS Target NMHC Species
Total Non-Methane Organic Compounds
Pre-Smoke Smoke Present
PPBC
Parts per
billion carbon
Daily Average (midnight to midnight)

18. The Role of the Smoke: VOCs
June 8, 2015,
1:00pm CDT
VOCs increased after cold front passage in
both Indian and in Maryland, coincident with
smoke presence
Suggests increase in VOCs is at least
partially due to smoke
Maximum running 24-hour “box-car”
average during smoke was
≈120ppbc in Indiana
≈75ppbc in Maryland (62% of IN)
VOC loss along smoke trek?
In Maryland, VOCs peaked on June 11
Approx 50% increase in NMOC during
daylight hours on June 11 vs June 10
50%

19. Wildfire VOC Species*
Besides Propene, all VOC species
identified as potential emissions
from wildfires and available in
canisters showed a 33-50%
increase from 6 days before the
wild fires on June, 5 with a
similar (38-60%) drop 6 days
later on June 17.
MIR: 9.08 MIR: 0.31
MIR: 0.81 MIR: 11.58
EXAVG: Average concentration during
exceedance days (2010-2012)
MIR: Maximum Incremental Reactivity
EXAVG: 1.32
MIR: 3.97 MIR: 10.61
EXAVG: 8.6
EXAVG: 0.86 EXAVG: 0.63
EXAVG: 3.58 EXAVG: 3.57
6/5 6/11 6/17
24-Hour Target PAMS VOC Canister Data
*Unless noted, VOC methods are (126)
*All units are PPBC
Source: Acefaw Belay, MDE Lab; AQS
Ethene Ethane
Benzene
Propene
Toluene Xylenes

20. Why the Delay in Ozone?
VOLATILE ORGANIC COMPOUNDS
Sum PAMS Target NMHC Species (ppbc)
Essex, MD
Hourly Chromatograph Data
June 9, 2015 June 10, 2015 June 11, 2015 June 12, 2015
Ozone production hours
(9am – 7pm) average
daily concentration
34.61 ppbc 36.08 ppbc 54.32 ppbc 44.86 ppbc
50% increase
This is with a
clean bay breeze!

21. Leading VOC Changes
Since ozone did not increase with the immediate arrival of the smoke, it is good to compare VOC
species between 6/10 (first full day of smoke) and 6/11 (day of ozone increase).
Essex Hourly:
Molecule (ppbc % change 6/10 to 6/11)
2-Methylheptane (500%)
n-Decane (331.8%)
n-Nonane (264.5%)
Methylcyclopentane (249%)
Methylcyclohexane (168.6%)
3-Methylheptane (152%)
3-Methylpentane (151%)
Cyclopentane (122.4%)
2-Methylhexane (116.2%)
n-Octane (110%)
Isoprene (112%)
By absolute concentration increase, isoprene and isopentane (96%
increase) dominate all others at 2.22 and 2.06 ppbc change, respectfully,
between 6/10 and 6/11.
Other leading wildfire smoke
indicators: After CO₂, CO and CH₄,
the largest emission factors are:
Formaldehyde (not yet available)
methanol, (not available)
pinenes(not yet available)
Ethene (yes)
NO2 (yes)
HCN (cyanide) (not available)
Ethane (yes)
Benzene (yes)
propene (yes)
Toluene (yes)
Xylene (yes)
acetone and CH₃CN (not available)
SW Baltimore
Fire

22. VOLATILE ORGANIC COMPOUNDS
Isoprene (ppbc) @ ESSEX chromatograph
Ozone production hours
(9am – 7pm) average
daily concentration
June 9, 2015 June 10, 2015 June 11, 2015 June 12, 2015
2.0 ppbc 1.96 ppbc 4.18 ppbc 4.2 ppbc
112% increase
ISOPRENE24-hour Canister (ppbc) 3-hour Canister (ppbc)

23. •Carbon Monoxide (Wildfire Tracer; Mobile Exhaust) peaked on June 11.
•NOz peaked on June 11
• Sharp drop-off of both pollutants on June 12, just before noon
NOz was extracted from Beltsville CASTNET site (~6km southeast of HUB)
Carbon Monoxide and NOz
CO and NOZ Surface Concentrations
9 - 12 June, 2015
NOz = NOy – NOx :: “Long Residence Species of NOx”

24. 70s
hourly
Piney Run
Hourly Ozone at 4pm EST, June 10, 2015
80s
hourly
•Piney Run had elevated ozone of
~60ppb through the early morning
of 6/11 under westerly transport.
•The next day Fair Hill had a
maximum 1-hr average of 118ppb!
Piney Run,
elevated site
Fair Hill 118ppb
Maryland Ozone
Monitors
6/10/2015 6/11/2015
Complications

25. Increased NOx Output
Approximate airshed on June 10
affecting Maryland on June 11
11% 24%
Double Jeopardy
•Increased temperature as warm air
moved in from the west increased
energy production
•Increased energy production increased
NOx output along Ohio River Valley
•In presence of smoke: ozone
production
•Maryland produced its own ozone with
local emissions in the presence of
smoke, but with a double jeopardy
created in Ohio the previous day
NOxTons
Transport!

26. Emissions of Indiana, Ohio, West Virginia, Virginia, Pennsylvania, Maryland and
the District of Columbia were summed together on a monthly basis
Transport yes, but….
Lowest emissions in the
last 7 years (ever?)

27. Hourly PM2.5 data from all
Maryland monitors
1) Black Carbon reached peak on June 11
a. Black Carbon is a smoke indicator – highest BC with
highest ozone!
2) “Delta-C” is a proxy wood smoke indicator – reached peak
on June 11
3) Delta-C goes to zero morning of June 12 but quickly rises
after sunrise (same as ozone) – mixing from residual layer??
4) Dramatic drop off in Black Carbon coincident with ozone
decrease on June 12, in the middle of a 90°F day!!!
2)
1) 3) 4)

28. a
WIND PROFILER – Beltsville, MD
b
42
4
4
12
10
8
6
6
Ozonesonde
Beltsville surface
O3 (bottom)
noise, clouds,
smoke
Very clean air at 2km above the
Nocturnal LLJ
Residual layer of ~80ppb at 1km.

29. Smoke clears after
approximately 1415 UTC
from HUB (10:15am)

30. Bay Breeze Influence on 11 June, 2015
11 June, 2015 (EST)
No exceedance with
Bay Breeze
Bay Breeze
Chesapeake Bay Breeze kept Edgewood and Essex from
Exceeding the ozone standard
Ozone dropped as marine air moved over monitors
Fine Particles dropped by 5µg m-3 at Edgewood coincident
with ozone drop
Suggests less smoke present over bay – consistent with
gradient from south to north
Presents Exceptional Event Issues

31. How Much Ozone from Smoke?
June 10,
2015
NOAA AQ MODEL SERVES AS A
“WHAT IF” GUIDE
•Smoke not captured in model
Large under-
prediction by the
NOAA model
June 11,
2015

32. NOAA Maximum 8hr
Ozone: Colored area
Ozone Monitors
Model Error Significance
•Model prediction minus observed 8-
hour ozone at all monitors
•Compared errors on June 11, 2015
(Smoke Event) with other “hot” days
(>90°F)
•Tested the variance of errors between
smoke day and non-smoke day
•F-test shows the variances are different
with statistical significance at the 95%
confidence level
For Maryland monitors north of DC,
ozone contribution from smoke is
approximately 14ppb.
Range: 7.6ppb – 30ppb
Ohio Error:
18-21ppb

33. Potassium Ion (K+)
Organic Carbon

34. Conclusions
• Smoke from Canadian wildfires was transported to
Maryland on June 11, 2015 and caused Maryland’s
worst air quality event since 2012
• Enhanced concentrations of VOCs within the smoke
exacerbated from local and transported NOx
promoted in combination with quickly rising
temperatures promoted ozone formation
• Preliminary analysis using operational model
guidance that did not include smoke emissions
suggests the smoke contributed on average 14ppb
of ozone to the 8-hour average

35. APPENDIX
NOAA model ozone error (Model
minus Observed maximum 8-hour
average) June 11, 2015

36. 2015 Maryland Ozone Summary*Metropolitan Statistical Area (Group Number)
Dailymax8-hourozoneconc.(ppb)
Dailynumberofsiteswithanoccurrence
1 2 3 4 5 6
Aldino
Davidsonville
Edgewood
Essex
Furley
Padonia
SouthCarroll
Calvert
PGEquest.Ctr.
Frederick
Airport
HowardU.
Beltsville*
Rockville
So.Maryland
FairHill
Blackwater
NWR*
Millington
HornPoint
Hagerstown
PineyRun
2014 Design
Value 73 74 75 72 64 72 69 73 76 70 70 75 68 71 77 70 74 73 67 68
06/11/2015 83 81 88 86 83 100 100 6
08/07/2015 79 79 1
08/15/2015 76 76 1
9/02/2015 88 77 88 2
9/04/2015 80 78 79 80 3
9/16/2015 76 82 78 76 81 79 82 6
9/17/2015 83 82 77 78 83 4
9/18/2015 76 78 78 2
2015 DV 70 69 71 68 65 71 67 68 69 67 68 69 68 66 73 66 69 64 65 64
Number of days >75ppb
2015: 8
2014: 5
2013: 9
2012: 30
2011: 29
2010: 43
2009: 11
2015 Summary:
1) Second fewest since 1980
2) Four days with potential smoke influence; three
were exceedance days: Only 5 non-smoke exceedances
3) Two “single-monitor” exceedances
4) No “old school” exceedances
In 2015:
•8 days above
75ppb
*data is
preliminary

37. 2015 Maryland Ozone SummaryMetropolitan Statistical Area (Group Number)
Dailymax8-hourozoneconc.(ppb)
Dailynumberofsiteswithanoccurrence
1 2 3 4 5 6
Aldino
Davidsonville
Edgewood
Essex
Furley
Padonia
SouthCarroll
Calvert
PGEquest.Ctr.
Frederick
Airport
HowardU.
Beltsville*
Rockville
So.Maryland
FairHill
Blackwater
NWR*
Millington
HornPoint
Hagerstown
PineyRun
2014 Design
Value 73 74 75 72 64 72 69 73 76 70 70 75 68 71 77 70 74 73 67 68
06/11/2015 83 74 75 81 75 88 86 83 100 73 100 10
08/07/2015 79 79 1
08/15/2015 76 71 76 2
9/02/2015 72 88 74 72 73 77 88 6
9/04/2015 80 74 74 78 79 72 74 72 80 8
9/16/2015 76 72 82 78 76 81 79 72 72 82 9
9/17/2015 74 72 83 82 77 78 74 83 7
9/18/2015 75 76 78 78 3
2015 DV 70 69 71 68 65 71 67 68 69 67 68 69 68 66 73 66 69 64 65 64
Number of days >70ppb
2015: 19
2014: 12
2013: 19
2012: 42
2011: 46
2010: 61
2009: 20
In 2015:
•19 days
above 70ppb
*data is preliminary
Table shown is for comparison to exceedances at 75ppb only
and does not reflect all 70ppb exceedance days in 2015

38. Courtesy Dr. John
Sullivan, UMBC/NASA;
Do not redistribute
without permission
(2:51pm EDT)
Ozonesonde
launched from
Beltsville, MD
2:51pm,
June 11, 2015
Large concentrations
of ozone through the
entire troposphere
1.8km
PBLH

39. June 12, 2015
Ozone
june9
<VALUE>
<50
<50
55 - 60
60 - 65
65 - 70
70 - 75
>75
ppb
June 12, 2015
(µg/m3)
Maximum 8-Hour Ozone
24-Hour Average PM2.5

41. Hourly VOCs at Essex, 6/11/2015
Bay Breeze

42. Contact Information:
Joel Dreessen
Joel.Dreessen@maryland.gov
410-537-3296