Martin O’Malley, Governor | Anthony G. Brown, Lt. Governor | Robert M. Summers, Ph.D., Secretary

PM2.5 Prediction & Analysis:Maryland’s Toolbox

Laura Warren, Senior Meteorologist

National Air Quality Conference

February 11, 2014

PM2.5 Prediction & Analysis

• Background• PM2.5 Progress

• Climatology

• Forecasting & Analysis Tools

• Case Studies

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Progress with PM2.5

• EPA revised the annual PM2.5 NAAQS from 15 to 12 ug/m3 in 2012• Retained the 24-hour

NAAQS of 35 ug/m3

• Many areas already meet the new annual NAAQS

• Many areas also already meet the 24-hour PM2.5 NAAQS of 1997 and 2006

Credit: EPA3

Progress with PM2.5 in Maryland

• Maryland is measuring clean data with both the annual and the daily PM2.5 standards

• Seeking redesignation to attainment status from EPA for Baltimore and Washington, D.C. nonattainment areas

• Maryland Healthy Air Act and other state, regional, and federal control strategies have played a large role in this improvement

15.8 15.914.5

11.7 11.3

17.1

11.1

12.915.616.215.9

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2002 2004 2006 2008 2010 2012

Ann

ual P

M2

.5 (

ug/m

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Annual Fine Particles in Maryland41 41 39

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2930

42 4137

3329

2002 2004 2006 2008 2010 2012

Dai

ly P

M2.

5 (u

g/m

3 )

0

10

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50Daily Fine Particles in Maryland

Previous NAAQS

Current NAAQS

Current NAAQS

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PM2.5 Composition

• Sulfate is the largest component at nearly 30%

• Organic carbon is second at about 25%

• Nitrate and ammonium are about 10% each

• During the summer, sulfate contributes most to PM2.5 while nitrate drives wintertime trends

Dust3%

Elemental Carbon5%

Organic Carbon25%

Sulfate27%

Nitrate11%

Ammonium12%

Other17%

PM2.5 Composition at Essex, MD2004 – 2006

Credit: MDE, 20085

Maryland PM2.5 Climatology

• Seasonally, PM2.5 exhibits 2 maximums• June – August

• Late December – February, depending on the region

• 5 exceedance days per year are observed on average• 4 exceedance days in 2013

Credit: W. F. Ryan & N. T. Wiles, 2012

Metropolitan Baltimore 7-Day Running Average 24-Hour PM2.5

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Revised PM2.5 AQI

• Revised AQI effective March 2013• Changed low Moderate

range from 15.5 to 12.1 ug/m3

• No change to Code Orange+

• Impacts on Maryland• About 70 more Moderate

days for PM2.5

More information on Maryland and the revised AQI is here.

Change in 24-Hour PM2.5 AQI for Maryland

0.2 days

5 days

0 50 100 150 200 250

Good

Moderate

USG

Unhealthy

Average No. of Days for 5 Years (2008-2012)

Previous AQI

Revised AQI

+70 days

No Change in USG, Unhealthy, Very Unhealthy

AQI Days

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Prediction & Analysis

• Tools used by MDE for PM2.5 will be highlighted from multiple perspectives:• Air quality forecasting• Poor air quality case studies

• Forecast verification• Understanding severe episodes• Exceptional events

• Unusual or naturally occurring events that are not reasonably controllable causing an exceedance of the NAAQS

• Clear, causal relationship between the measurement and the event

• Measured concentration were in excess of normal historical fluctuations

• Prove there would have been no exceedance but for the event

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Well-Known Forecasting Tools

• AirNow-Tech• Navigator

• Data query

• WPC products including the model diagnostics discussion

• Meteorological models• NCEP

• Weather Underground

• Penn State e-WALL

• HYSPLIT trajectories• Air quality models

Credit: AirNow, Environment Canada, NASA, NCAR, NCDAQ, NOAA, NRL; Initial design: D. Nguyen9

Airmass Transport

• HYSPLIT Trajectories• Web-based

• Forecasting and retrospective analysis

• Comparisons between GFS vs. NAM trajectories

• PC-based for retrospective analysis• Generate multiple

trajectories in a batch process

• Cluster analysis can be further investigating using statistical software like R or MeteoInfo TrajStat

Cluster Analysis: Jennifer Hains, PhD10

Airmass Transport

• HYSPLIT Dispersion Model• Can provide a forecaster with a

rough idea of a wildfire’s PM2.5 transport

• Must run the dispersion model as a “prescribed burn”

• Model needs to know…• Coordinates of the fire location• Acreage of the burn area• Inciweb website may have this

information available• Graphics or KML is generated

at the user’s request

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Boundary Layer Height

• The planetary boundary layer height (PBL) is important, especially for wintertime episodes

• Obtained from:• NWS station skew-T’s

• Lidars

• Radar wind profilers (RWP) and radio acoustic sounding systems (RASS)• Virtual temperature• Signal-to-noise ratio

Credit: NASA, Plymouth State University12

Boundary Layer Height

• Signal-to-Noise Ratio• Comparable to backscatter

from lidar• Useful for post analysis• PBL heights analyzed

subjectively or by an algorithm developed by UMBC

dB

Source: MDE

PBL analyzed by MDE meteorologist

Residual layer

Source: UMBC Location: Baltimore, MD

Residual layer

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Fire Detection

• NESDIS Hazard Mapping System (HMS)• Hotspots and smoke plumes by

satellite analysts

• NASA FIRMS MODIS email alerts

• GOES-East Eastern Region satellite imagery• Satellite loops provided with

visual enhancements to aid in smoke plume detection

• RGB satellite products• MODIS, VIIRS, GOES• Can illustrate the direction of

smoke transport for exceptional event analysis

Credit: NOAA

Smoke

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Aerosol Optical Depth

• Satellite measurements from MODIS, VIIRS, and GASP• Helpful for spatial

representation of aerosol measurements

• Most often accessed via the IDEA website• Comparisons of AOD

between each satellite sensor

• Very useful interactive platform for VIIRS products

• Easy to compare AOD for five different quality levels

Credit: IDEA, NASA15

Aerosol Optical Depth

• AERONET• Ground-based remote sensing

to detect parameters such as AOT and aerosol size distribution

• Higher temporal resolution than satellite AOD

• Data quality levels of 1.0, 1.5, 2.0 to select depending on use

• AERONET Synergy Tool, optimized for episode analysis, provides wide range of datasets

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Air Quality Models

• NOAA Developmental PM2.5

• Currently used in a qualitative sense, and it seems to do well in this way

• NOAA Operational Smoke• Used to indicate potential

impacts to Maryland from nearby fires

• NRL Operational Aerosol• Smoke, sulfate, dust• Sulfate can be helpful in

summer• Comparisons between models

• NOAA smoke vs. PM2.5 for exceptional event “but for” case

• NRL vs. NOAA smoke

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Quebec Wildfires 2002

• Air quality influenced by smoke from Quebec wildfires on July 7 - 9, 2002

• Northwesterly flow, usually associated with clean air, due to high pressure in the Midwest and low pressure in the Gulf of Maine

• Resulting air quality:• Code Red (Unhealthy) for

PM2.5

• Code Purple (Very Unhealthy) for ozone

Credit: Environment Canada, NOAA, NASA

Predominant

Flow

Surface Analysis12z July 7, 2002

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Quebec Wildfires 2002

In this case, limited data at quality level 1.5, but AOD indicates a rising trend

AOD size distribution

shows primarily fine particles

Smoke descending throughout the day

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Good/Moderate Episode 2013

• PM2.5 forecasting for the East Coast is often a battle between Good/Moderate AQI

• September 8, 2013• A mix of Good and Moderate

conditions

• 24-hour averages:11 – 18 ug/m3

• Hourly averages:3 – 30 ug/m3

• Warm and moist conditions ahead of a slow moving cold front

Credit: AirNow-Tech, EPA AirData

Hourly PM2.5 in MD & VA Sept. 8, 2013

Surface Analysis12z Sept 8, 2013

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Good/Moderate Episode 2013

• AOD is somewhat elevated on the 8th

• GASP indicated higher AOD than MODIS

• AOD coverage seems sparse in our region, sometimes due to cloud cover

• VIIRS cloud screening and other QC processes tend to throw out more data than MODIS, an issue being investigated by NOAA

• NOAA developmental PM2.5 model indicated concentrations may not return to the Good range on the 8th

Credit: NOAA WPC, IDEA21

Winter Stagnation 2013

• A rare episode of PM2.5 exceedance days• December 2 – 4, 2013

• Highest 24-hour average was on the 3rd at Hagerstown measured 45.7 ug/m3

• Highest values were in rural valley areas like Hagerstown, but urban areas weren’t far behind

• Persistent high pressure system caused stagnation• Some sites (Fairhill) showed the

classic diurnal wintertime pattern

• High nocturnal PM2.5 followed by relief when the afternoon inversion broke

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PM

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nce

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g/m

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Hour (EST)

Maryland Area PM2.5 MonitorsNov. 30 - Dec. 5, 2013

HagerstownWinchester, VAOldtownEdgewoodFairhillNAAQS

Surface Analysis00z Dec. 4, 2013

24-Hour Average PM2.5Dec. 4, 2013

11/30/13 12/1/13 12/2/13 12/3/13 12/4/13 12/5/13

Credit: NOAA WPC, AirNow-Tech22

Winter Stagnation 2013

• In addition to mostly calm winds through the period, a strong temperature inversion trapped pollutants in a shallow boundary layer

• RASS shows PBL height varying from 100 – 500m on the 4th

• Algorithm using the wind profiler’s signal-to-noise ratio (SNR) shows PBL heights between 200 – 600m• Profilers’ SNR values are more defined in humid atmospheres and, as a result, the

algorithm may perform best in the summer

Credit: NOAA/MADIS

PBL PBL

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Summary

• Many meteorological products and tools geared toward aerosols• Airmass transport through HYSPLIT trajectory and dispersion model

products• Boundary layer heights via skew-T, lidar, radar wind profilers, and RASS• Many fire detection tools through NASA and NOAA• AOD derived from satellite sensors MODIS, VIIRS, and GASP, and

ground-based instruments through AERONET

• Aerosol models run by NOAA for smoke and PM2.5 as well as by NRL/Monterey for smoke, sulfate, and dust

• Future Products: Research is ongoing to improve spatial resolution for ground-level PM2.5 through the integration of satellite data, particularly in air monitor sparse areas• AirNow Satellite Data Processor (ASDP)• NASA Air Quality Applied Sciences Team (AQAST)• NASA DISCOVER-AQ Mission

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Resources

• Measurements:• NASA AERONET data synergy tool• NASA FIRMS MODIS fire alerts• NASA MicroPulse Lidar Network

(MPLNET)• NOAA/MADIS

Cooperative Agency Profilers• NOAA/NESDIS

Hazard Mapping System• NOAA/NESDIS IDEA• NOAA/NESDIS satellite loops with

enhancements• NOAA/NCDC recent snowfall maps• NOAA/NOHRSC

national snow analysis• UMBC Smog Blog

• Models:• MeteoInfo TrajStat• NOAA/ARL HYSPLIT, more on

automation here

• NOAA PM2.5 Developmental Model• NOAA Smoke Model• NRL/Monterey Aerosol Model

• References:• Compton, J., R. Delgado, T. Berkoff, and R. Hoff,

2013: Determination of planetary boundary layer height on short spatial and temporal scales: A demonstration of the Covariance Wavelet Transform in ground based wind profiler and lidar measurements. J. Atmos. Oceanic Technol. doi:10.1175/JTECHD-12-00116.1.

• Ryan, W. F. and N. T. Wiles, 2012: PM2.5 Forecast Climatology for Maryland. 28 pp.

• Maryland Department of the Environment (MDE), 2008: Appendix G-11-2: Weight of Evidence Report Appendices. Baltimore Nonattainment Area PM2.5 State Implementation Plan and Base Year Inventory. SIP Number: 08-04. 1735 pp.

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Questions?

Laura WarrenAir Monitoring Program

Maryland Department of the Environment(410) 537-3122 | Laura.Warren@Maryland.gov

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