Intervention Strategies for Intervention Strategies for Woodstove HomesWoodstove Homes

Tony Ward, Ph.D.Tony Ward, Ph.D.The University of MontanaThe University of Montana

Center for Environmental Health SciencesCenter for Environmental Health Sciences

June 16, 2011June 16, 2011

Mexico City, MexicoMexico City, Mexico

Beijing, ChinaBeijing, China

Los Angeles, CaliforniaLos Angeles, California

Source: http://www.epa.qld.gov.au/environmental_management/air/air_quality_monitoring/

Ambient PMAmbient PM

EPA 24-Hour PMEPA 24-Hour PM2.52.5

Nonattainment AreasNonattainment Areas*As of Aug 2010

National Ambient Air Quality Standard (NAAQS): Annual, 15 μg/m3; 24-hr, 35 μg/m3.

WoodstovesWoodstoves

Chemical Mass Balance (CMB) Chemical Mass Balance (CMB) PMPM2.52.5 Source Apportionment Source Apportionment

• Computer modeling to determine what the sources of PM2.5 are in the airsheds.

1) Collect PM2.5 air samples.

2) Analyze the air samples for chemical species.

3) Use an EPA computer model (CMB) to apportion the sources.

Air SamplersAir Samplers

Sources of Hamilton PMSources of Hamilton PM2.52.5

Winter 2007/2008Winter 2007/2008

Residential Wood

Combustion75.8%

Unexplained1.5%

NH4NO317.4%

SO44.4%

Street Sand1.0%

Average PM2.5:11.0 μg/m3

11/2/07 – 3/1/08

Sources of Butte PMSources of Butte PM2.52.5

Winter 2007/2008Winter 2007/2008

Diesel0.2%

Unexplained3.2%

Residential Wood Combustion

77.0%

Autos3.6%

NH4NO310.2%

SO43.2%

Street Sand2.6%

Average PM2.5: 13.5 μg/m3

11/8/07 – 3/1/08

Sources of Helena PMSources of Helena PM2.52.5

Winter 2007/2008Winter 2007/2008Street Sand

2.9%

SO44.9%

NH4NO318.9%

Autos2.4%

RWC66.4%

Cement Kiln0.5%

Diesel0.3%

Unexplained3.7%

Average PM2.5:9.0 μg/m3

11/2/07 – 3/1/08

Sources of Kalispell PMSources of Kalispell PM2.52.5

Winter 2008/2009Winter 2008/2009

Average PM2.5:9.0 μg/m3

11/2/07 – 3/1/08

Street Sand1.8%

Sulfate3.8%

Ammonium Nitrate15.5%

Diesel6.9%

Automobiles0.8%

Unknown2.3%

Residential Wood Combustion

68.8%

Average PM2.5:10.1 μg/m3

11/2/08 – 2/24/09

Fairbanks State Building CMB ResultsFairbanks State Building CMB Results(November 11, 2008 – April 7, 2009)(November 11, 2008 – April 7, 2009)

Fairbanks - North Pole CMB ResultsFairbanks - North Pole CMB Results(January 25, 2009 – April 7, 2009)(January 25, 2009 – April 7, 2009)

WoodstovesWoodstoves

• In the rural Northern Rocky Mountains of western Montana, PM2.5 is the major ambient air pollution issue (especially during the winter months).

• The majority of the wintertime PM2.5 comes from woodstoves (56 – 77%).

Ward T, Lange T. The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities. Environ Pollut. 2010 Mar;158(3):723-9.

Woodstove ChangeoutsWoodstove Changeouts

• Woodstove changeouts are becoming a common tool targeting ambient woodsmoke PM2.5.

• A good example is Libby, Montana.

Woodstove ChangeoutWoodstove Changeout

Old stove40-60 g smoke/hr

EPA-certified stove2-5 g smoke/hr

PM2.5 Nonattainment Areas (2003)

NAAQS: Annual, 15 μg/m3; 24-hr was 65 μg/m3.

PMPM2.52.5 Seasonal Trends Seasonal TrendsCourthouse Annex-Libby

AIRS Code 300530018 POC 5 (ROUTINE)

0

10

20

30

40

50

60

10/1

6/01

12/1

0/01

2/3/

02

3/30

/02

5/24

/02

7/18

/02

9/11

/02

11/5

/02

12/3

0/02

2/23

/03

4/19

/03

6/13

/03

8/7/

03

10/1

/03

11/2

5/03

1/19

/04

3/14

/04

5/8/

04

7/2/

04

8/26

/04

10/2

0/04

12/1

4/04

2/7/

05

4/3/

05

5/28

/05

7/22

/05

9/15

/05

11/9

/05

1/3/

06

2/27

/06

4/23

/06

6/17

/06

8/11

/06

10/5

/06

11/2

9/06

1/23

/07

3/19

/07

5/13

/07

7/7/

07

8/31

/07

Date

Co

nce

ntr

atio

n (

µg

/m³)

PM2.5

Winter 2003/2004 Libby, Montana Winter 2003/2004 Libby, Montana Sources of PMSources of PM2.52.5

Residential Wood

Combustion82%

Diesel4%

Autos7%

NH4NO35%

SO42%

Street Sand0%

Avg PM2.5: 28.2 ug/m3

Ward, T.J., Rinehart, L.R., and Lange, T., 2006. The 2003/2004 Libby, Montana PM2.5 source apportionment research study, Aerosol Science and Technology, 40: 166-177.

Temperature InversionsTemperature Inversions

WoodstovesWoodstoves

Libby Woodstove Changeout ProgramLibby Woodstove Changeout Program

Funding provided by Montana DEQ, EPA, and HPBA.

Libby Woodstove Changeout ProgramLibby Woodstove Changeout Program

• Nearly 1,200 old woodstoves were changed out, modified, or surrendered between 2005 and 2008.

Wood Stove Change-out Program: Wood Stove Change-out Program: A Natural ExperimentA Natural Experiment

Conduct prospective multi-year study to assess changes in woodsmoke PM2.5 and impact on health of school children following the intervention.

1. Monitor changes in ambient PM2.5.

2. Monitor changes in school indoor PM2.5.

3. Evaluate the change in residential indoor PM2.5 following a changeout.

4. Track changes in reporting of symptoms and illness-related absences among students.

PM2.5 in Libby and NAAQS

PM2.5 in Libby and NAAQS

Key Finding - LibbyKey Finding - Libby

• A large woodstove changeout can be effective in reducing ambient levels of PM2.5.

Bergauff, M.A., Ward, T.J., Noonan, C.W., and Palmer C.P. 2009. The effect of a woodstove changeout on ambient levels of PM2.5 and chemical tracers for woodsmoke in Libby, Montana. Atmospheric Environment, 43, 2938-2943.

Ward, T.J., Palmer, C.P., Houck, J.E., Navidi, W.C., Geinitz, S., and Noonan, C.W., 2009. A community woodstove changeout and impact on ambient concentrations of polycyclic aromatic hydrocarbons. Environmental Science & Technology, 43(14), 5345–5350.

Ward, T. J., Palmer, C. P., and Noonan, C. W., 2010, PM2.5 source apportionment following a large woodstove changeout program in Libby, Montana. Journal of the Air and Waste Management Association, 60: 688-693.

What about the impact of a woodstove changeout on indoor levels of PM2.5?

1) Libby, Montana.

2) Nez Perce Woodstove Changeout Program.

Exposure Assessment Within HomesExposure Assessment Within Homes

Libby 2006/2007 Residential PM2.5 Program

PM2.5 Mass - Home 4A

0

100

200

300

400

500

600

700

800

1

Time

Co

nce

ntr

atio

n (

ug

/m3)

15:22

19:53

06:30

Start Sampling:10/25/06 @ 14:00

End Sampling:10/26/06 @ 14:00

Avg = 131.8 μg/m3

Before Changeout

2006/2007 Libby Residential 2006/2007 Libby Residential PMPM2.52.5 Sampling Program Sampling Program

Sampling focused on 20 homes containing woodstoves.

24-hour PM2.5 samplingPre-changeout period (Oct/Nov 2006).

Post-changeout (Dec 2006 – Feb 2007).

The goal of the program was to evaluate the impact of this “intervention” on indoor air quality within the home.

Libby PM2.5 Mass Results – Pre and Post Stove Changeout

Pre-changeout avg PM2.5: 53.4 μg/m3 Post-changeout avg PM2.5: 15.0 μg/m3

0

20

40

60

80

100

120

140

Home 1

Home 3

Home 5

Home 6

Home 7

Home 8

Home 9

Home 1

0

Home 1

1

Home 1

2

Home 1

3

Home 1

4

Home 1

5

Home 1

7

Home 1

8

Home 2

0

PM

2.5

Con

cen

trat

ion

(u

g/m

3 )

Pre Avg PM2.5

Post Avg PM2.5

PMPM2.52.5 Maximum Spikes – Maximum Spikes –

Pre and Post Stove ChangeoutPre and Post Stove Changeout

Pre-changeout spike avg: 434 μg/m3 Post-changeout spike avg: 103 μg/m3

0

200

400

600

800

1000

1200

1400

Home 1

Home 3

Home 5

Home 6

Home 7

Home 8

Home 9

Home 10

Home 11

Home 12

Home 13

Home 14

Home 15

Home 17

Home 18

Home 20

PM

2.5

Con

cent

rati

on (

ug/m

3 )

Pre- PM2.5

Post- PM2.5

Libby Residential Libby Residential Program, cont.Program, cont.

Did the stove changeout work Did the stove changeout work over time?over time?

Ward, T.J., Palmer, C., Bergauff, M., Hooper, K., and Noonan, C., 2008. Results of a residential indoor PM2.5 sampling program before and after a woodstove changeout, Indoor Air, 18: 408–415.

Followup PMFollowup PM2.52.5 Indoor Study Indoor Study

Air sampling was conducted in a total of 26 woodstove homes.

Five phases:

Phase 1 = pre stove change, 2006/2007 winter.

Phase 2 = post change, same winter.

Phase 3 = post change, 2nd 2007/2008 winter.

Phase 4 = post change, 3rd 2007/2008 winter.

Phase 5 = post change, 4th 2008/2009 winter.

Libby Residential Study (winters of 2006/2007 - 2008/2009 (3 winters)

Pre-changeout avg PM2.5: 63.2 µg/m3 Post-changeout avg PM2.5: 28.9 µg/m3

Results of Multi-Winter Results of Multi-Winter Residential StudyResidential Study

• Overall reductions following the wood stove changeout were observed in 16 of 21 homes.

• High variability was observed for post-changeout sampling within some homes, but 14 of the 21 homes still had lower PM2.5 concentrations for all post-changeout sampling compared to pre-changeout PM2.5 concentrations.

Nez Perce Woodstove Nez Perce Woodstove Changeout ProgramChangeout Program

Nez Perce Woodstove ChangeoutNez Perce Woodstove Changeout

• Conducted during the winters of 2006/2007, 2007/2008, and 2008/2009.

• Kamiah and Lapwai, Idaho on the Nez Perce Reservation.

• 16 homes.

Nez Perce Woodstove Changeout Nez Perce Woodstove Changeout PMPM2.52.5 Mass Results Mass Results

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

200.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Home

PM

2.5

Con

cent

rati

on (

ug/m

3 )

Avg PM2.5 Pre (ug/m3)

Avg PM2.5 Post (ug/m3)

Pre-changeout avg PM2.5: 43.1 μg/m3 Post-changeout avg PM2.5: 126.0 μg/m3

~278% PM2.5

increase

Importance of TrainingImportance of Training

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

Pre Post 1 Post 2

Sampling Event

PM

2.5

Co

nce

ntr

atio

n (

ug

/m3 )

Home 2

Home 6

Home 11

Home 13

PM2.5 Mass (µg/m3) Measured in Homes Following Outreach/Education.

Ward, T.J., Boulafentis, J., Simpson, J., Hester, C., Moliga, T., Warden, K., and Noonan, C.W., 2011. Results of the Nez Perce woodstove changeout program, Science of the Total Environment, 409, 664-670.

Woodstove ChangeoutsWoodstove Changeouts

• Effective in reducing ambient PM2.5.

• Expensive (~$1500 - $4500).

• Learning curve.

• Results can be variable for indoor air.

Another Indoor InterventionAnother Indoor Intervention- Filtration Units -- Filtration Units -

Overall Averages for the 3M Study

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

11 Samples Averaged

Overall Averages Without Outliers

PM

2.5

ug

/m3

With a 3M Filter

Without a 3M Filter

Avg ~50% PM2.5 Reduction in Woodstove Homes

A Randomized Trial for Indoor A Randomized Trial for Indoor Smoke (ARTIS)Smoke (ARTIS)

• 5-year, NIEHS funded study.

• The Primary Aim of this study is to assess the impact on quality of life among asthmatic children following interventions that reduce in-home woodsmoke PM exposures.

Study Design: Study Design: Randomized Randomized TrialTrial

Recruitment

Randomization

Group 1 (n=36)

Group 2 (n=36)

Group 3 (n=36)

Winter #1: Baselines Exposure and Health Outcomes Measures

Winter #2: Post-intervention Exposure

and Health Outcomes Measures

Tx1: EPA-Certified

Woodstove

Tx2: Active Air Filter Units In two rooms

Tx3: Inactive Air Filter Units

(Placebo)

X

Health Outcome MeasuresHealth Outcome Measures

• PAQoL• Peak flow• Symptoms• eNO• Biol. samples

– EBC– Urine

Dr. Curtis Noonan

Indoor Air Sampling

ARTIS Preliminary ResultsARTIS Preliminary Results

SummarySummary

• Woodstoves are a significant source of PM2.5 in both ambient and indoor environments.

• Woodstove changeouts can be effective in reducing ambient wintertime PM2.5 – results are more variable indoors.

• Filtration units are consistently effective in improving indoor air in homes with woodstoves.

AcknowledgementsAcknowledgementsFunding• NIH Centers of Biomedical Research Excellence (p20-

RR017670).• Health Effects Institute (#4743-RFA04-4/06-4).• NIEHS (1R01ES016336-01; 3R01ES016336-02S1)• Montana Department of Environmental Quality (DEQ). • Alaska Department of Environmental Conservation

(DEC, Barbara Trost and Jim Connor).• EPA Region 10 (Mary Manous).• Nez Perce ERWM (Johna Boulafentis and Julie

Simpson).• The 3M Corporation.• Toyota USA Foundation.

Thank you.Thank you.

Tony Ward(406) 243-4092Tony.Ward@umontana.edu

http://www.umt.edu/cehs/AirTox.html