Air Pollution in the Mid-Atlantic Region: Act Locally, Think Globally

Russell Dickerson et al.Department of Meteorology

University of MarylandCollege Park

Maryland Climate WorkshopAugust 7, 2003

Motivation

• Third worst ozone in America: Anne Arundel County, MD

• Mortality increases 0.5% for each 10 g m-3 PM2.5

Double in Northeast.

• Spatial scales larger than we thought.

• Need a full tool box to fix the problem.

• Avoid major strategic blunders.

Donora, PA

Annual mean visibility across the United states

(Data acquired from the IMPROVE network)

Washington, DC

Balitmore Exceedances of the 1hr NAAQS (1990- 2001)

02468

1012141618

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

Num

ber o

f Day

s The mean number of exceedances over the last 12 years is 10 days per year. 2001 with 9 exceedances, was an average year.Like 2000, July of 2001 was quite cool.

Balitmore Exceedances of the 1hr NAAQS (1990- 2002)

02468

1012141618

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Num

ber o

f Day

s The mean number of exceedances over the last 12 years is 10 days per year. 2001 with 9 exceedances, was an average year.2002 was an unusually hot year.

Good News

The ambient EC concentration decreased ~50% in 11 yr.

Smog Machine

SmogO3

PANetc

NO2

NO

NONO2

CO2, H2O, HNO3

NOx, VOCs

What are we doing about it?

Balanced Theory & Observations((RRegional egional AAtmospheric tmospheric MMeasurement easurement MModeling & odeling & PPrediction rediction PProgram)rogram)

ObservationsSurface:

Shenandoah National Park, VAFort Meade, MDPhiladelphia, PAGreenbelt, MD

AloftAztec AircraftProfilerSondes

Remote (NASA)TES/OMI etc.MOPITT (CO)TOMS (O3)MODIS (particles)GOME (SO2, NO2…)SCIAMACHY

InputEmissions Inventories

Emissions Models(Chem Engineering)

MM5Dynamical Model4-km Resolution

Forecasting

Models 3ModularOpen CodeCollaborativew/EPA

Photochem.AerosolsTransportDeposition

• Where does our air pollution come from? Roughly 1/3 background, 1/3 regional, 1/3 local? (nonlinear problem).

• Why is smog (ozone) still a problem?Cleaner cars, but more cars, grandfathered industry, NOx emissions remain constant.

• Which air pollutants cause trouble? O3, PM2.5 (NOx, VOC, SO2 are precursors).

Aztec-F Research Aircraft N500ZAztec-F Research Aircraft N500ZGPS Position (°Lat, °Long)

Meteorology (T, RH, Pr, Palt)

Carbon Monoxide (CO)

Ozone (O3)

Sulfur Dioxide (SO2)

Aerosol Optical Properties:Absorption, Bap (565 nm)

Scattering, Bscat (450,550,700 nm)

GPS Winds (AIMMS-10 u,v components)

Aerosol Chemistry (PIXIE Streaker)

Aerosol Particle Size (MetOne)

6 cuts – Range 0.3-1.0 m

Westerly transport is often present when the highest ozone is observed in Maryland.

Power Plant NOx

Fort Meade, MD

Summer: Sulfate dominates.

Winter: Nitrate/carbonaceous particles play bigger roles.

Inorganic compounds ~50% (by mass)

Carbonaceous material ~40% (by mass)

Two Reservoir Model

afternoon midnightsunset sunrise noon

Free Atmosphere

Residual Layer

Stable Nocturnal Boundary Layer

Mixed Layer

Mixed Layer

surface layer surface layer surface layer0

1

2

Planetary Boundary

Layer

Low Level Jet

Hei

ght (

km)

Boundary Layer Height During Stable Conditions(High Pressure)

Low

Leve

l Jet

Location and Extent of Low-Level Jet

Because of its relatively thin vertical scale and inopportune temporal profile, determining the morphology low level jet until recently has been challenging.

Boundary layer wind profilers, aircraft work and finer scale numerical models are helping

resolve the phenomenon.

Do emissions estimates agree with observations?

Time of day

0 2 4 6 8 10 12 14 16 18 20 22 24

Rat

io o

f ETH

/VO

C

0.00

0.02

0.04

0.06

0.08

0.10

observationSMOKE

20km x 20km

Time of day

0 2 4 6 8 10 12 14 16 18 20 22 24

Rat

io o

f ETH

/VO

C0.00

0.02

0.04

0.06

0.08

0.10

observationSMOKE

28km x 28km

28 km x 28 km area20 km x 20 km area

Ethene/VOC, Essex, MD….

Time of day

0 2 4 6 8 10 12 14 16 18 20 22 24

Rat

io o

f VO

C(g

as)/V

OC

(tota

l)

0.0

0.2

0.4

0.6

UNMIXSMOKE

Site cell

Time of day

0 2 4 6 8 10 12 14 16 18 20 22 24

Rat

io o

f VO

C(g

as)/V

OC

(tota

l)

0.0

0.2

0.4

0.6

UNMIXSMOKE

3 cells x 3 cells

Ratio of gasoline VOC/total VOC

PAMS site cell 12 km x 12 km area

MODIS: August 9, 2001

“RGB” Aerosol Optical Depth at 550 nm

AOT0.8

0.0

Phili

BaltGSFC GSFC

Balt

Phili

Highest Ozone of the Summer

Ozone: Surface Network vs TOMS

Surface Analysis 00 UTC Aug 9, 2001

• Note front through New England

• Trof over Mid-Atlantic

Take-Home Message on Transport of Pollutants

All three modes of transport are important when the highest pollution values are observed in Maryland.

•Large scale ~ 800 km (~70-100 ppbv)(Much of the Eastern US)

•Medium scale ~ 200- 800 km(Carolinas to New England Region)

•Small scale ~ 100 km(N. Virginia to Baltimore,Baltimore to Philadelphia)

Areas of Influence

Conclusions

•Scale of problem large, but resolution needed great.

•Much of air pollution imported from out of state.

PM2.5 regional in summer, local in winter.

•PM2.5 & O3 may be related by more than.

•Will NOx reductions, by reducing oxidants, be more effective than SO2 for reducing PM2.5?

•Role of agriculture could be major.

•Balanced theory and experiment most powerful.

Discussion Topics

1. What is the most efficient way to improve air quality and reduce greenhouse forcing in MD?

NOx, SO2, NH3, VOC’s, all?

2. What is role of local vs regional emissions?

3. How will Maryland’s climate change?

4. What is the role of remote sensing in science/policy air pollution?

5. Policy: What are the nonlinearities lurking about? SO4 vs NO3, het chemistry, UV flux, NH3.

6. Emissions factors & inventories.

7. What can we do right? What needs improvement?

AcknowledgementsUMDRichard Calabrese, ENCHYuJin Choi, ENCHBruce Doddridge, METOSheryl Ehrman, ENCHRobert Hudson, METOJennifer Hains, CHEMLackson Marufu, METOCharles Piety, METOJeff Stehr, METOBrett Taubman, CHEMDa-Lin Zhang, METONASA/GSFCHolben, Kaufman, Levy, Thompson