Wood Stoves Acknowledgements Johna Boulafentis, Nez Perce Tony Ward, University of Montana

Wood Stove Interventions Wood stove changeouts (ambient and indoor). Filtration units (indoor). Best-burn practices (ambient and indoor). Wood banks (ambient).

Case Study - Libby Montana

PM 2.5 Nonattainment Areas (2003) NAAQS: Annual, 15 μg/m 3 ; 24-hr was 65 μg/m 3.

PM 2.5 Nonattainment Areas – 2006

Temperature Inversions Valley Locations

Wood stoves

Winter 2003/2004 Libby, Montana Sources of PM 2.5

MissoulaBelgradeButteHamiltonHelena Kalispell PM 2.5 Mass 13.7 ± ± ± ± ± ± 4.8 Sample Days Street Sand0.12 (0.8%)0.4 (3.8%)0.4 (2.6%)0.1 (1.0%)0.3 (2.9%) 0.21 (1.8%) NH 4 NO (18.7%)2.0 (19.7%)1.4 (10.2%)2.0 (17.4%)1.8 (18.9%) 1.8 (15.5%) SulfateND0.3 (3.4%)0.4 (3.2%)0.5 (4.4%)0.5 (4.9%) 0.43 (3.8%) Diesel0.71 (4.6%)0.04 (0.4%)0.03 (0.2%)ND0.03 (0.3%) 0.79 (6.9%) Autos0.1 (0.7%)0.2 (1.9%)0.5 (3.6%)ND0.2 (2.4%) 0.09 (0.8%) Wood Smoke8.6 (55.5%)7.0 (70.2%)10.9 (77.0%)8.6 (75.8%)6.3 (66.4%) 7.8 (68.8%) Industry2.9 (18.7%)ND 0.05 (0.5%)ND Unexplained 0.2 (1.0%)0.1 (0.7%)0.5 (3.2%)0.2 (1.5%)0.4 (3.7%) 0.2 (2.3%) CMB Source Estimates (μg/m 3, and % of Total Measured PM 2.5 )

Wood stoves In the rural Northern Rocky Mountains of western Montana, PM 2.5 is the major ambient air pollution issue (especially during the winter months). The majority of the wintertime PM 2.5 comes from wood stoves (56 – 77%). Ward T, Lange T. The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities. Environ Pollut Mar;158(3):723-9.

So what can be done? Wood stove changeouts have become a common tool targeting ambient wood smoke PM 2.5. A good example is Libby, Montana.

Wood Stove Changeout Old stove g smoke/hr EPA-certified stove 2-5 g smoke/hr

Wood Stove Changeout Program: A Natural Experiment Conduct prospective multi-year study to assess changes in wood smoke PM 2.5 and impact on health of school children following the intervention. 1.Monitor changes in ambient PM Monitor changes in school indoor PM Evaluate the change in residential indoor PM 2.5 following a changeout. 4.Track changes in reporting of symptoms and illness-related absences among students.

PM 2.5 in Libby and NAAQS

Key Finding - Libby A large woodstove changeout can be effective in reducing ambient levels of PM 2.5.

What about indoors?

Exposure assessment within homes

Wood stoves

15:22 19:53 06:30 Start Sampling: 14:00 End Sampling: 14:00 Avg = μg/m 3 Before Changeout

How does a wood stove changeout impact indoor air quality? Old stove g smoke/hr EPA-certified stove 2-5 g smoke/hr

2006/2007 Libby Residential PM 2.5 Sampling Program Sampling focused on 20 homes containing wood stoves. 24-hour PM 2.5 sampling Pre-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 PM 2.5 Mass Results – Pre and Post Stove Changeout Pre-changeout avg PM 2.5 : 53.4 μg/m 3 Post-changeout avg PM 2.5 : 15.0 μg/m 3

Results of Multi-Winter Residential Study Overall reductions following the wood stove changeout were observed in 16 of 21 homes.

Case Study - Nez Perce

Nez Perce Wood Stove 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 Wood Stove Changeout PM 2.5 Mass Results Pre-changeout avg PM 2.5 : 43.1 μg/m 3 Post-changeout avg PM 2.5 : μg/m 3 ~278% PM 2.5 increase

Nez Perce Wood Stove Changeout PM 2.5 Mass Results Pre-changeout avg PM 2.5 : 43.1 μg/m 3 Post-changeout avg PM 2.5 : μg/m 3 ~278% PM 2.5 increase

Importance of Training PM 2.5 Mass (µg/m 3 ) Measured in Homes Following Outreach/Education. Ward, T.J., Boulafentis, J., Simpson, J., Hester, C., Moliga, T., Warden, K., and Noonan, C.W., Results of the Nez Perce woodstove changeout program, Science of the Total Environment, 409,

Wood Stove Changeouts Effective in reducing ambient PM 2.5. Expensive (~$ $4500). Learning curve. Results can be variable for indoor air.

Filtration Units

A Randomized Trial for Indoor 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 wood smoke PM exposures.

Health Outcome Measures PAQoL Peak flow Symptoms eNO Biol. samples –EBC –Urine Dr. Curtis Noonan

Indoor Air Sampling

Preliminary results of ARTIS interventions 59% Reduction

Use of best-burn practices Education coupled with the use of inexpensive tools. Burn at proper temperatures (thermometer) °F is optimal.

Use of best-burn practices, cont. Burn dry, seasoned wood (moisture meter). <20% moisture is optimal.

Use of best-burn practices, cont. Don’t burn trash, etc. Stove maintenance (ash cleaning, clean out chimneys, etc). EPA Burn Wise Program

Summary – Change Outs Wood stoves are a significant source of PM 2.5 in both ambient and indoor environments. Wood stove changeouts can be effective in reducing ambient wintertime PM 2.5 – results are more variable indoors. Changeouts are expensive Training and Education on new stoves essential

Summary – Filtration Units Filtration units are consistently effective in improving indoor air in homes with wood stoves. Improves indoor air quality by ~60%, but does nothing for outdoors. Electricity costs are a concern and units can be noisy.

Summary – Burning Practices Best-burn practices are inexpensive and sustainable strategies. Education, outreach, and training are critical.

Summary – Other Considerations Each intervention should be culturally and regionally appropriate. Interventions need to be sustainable. Can we replace wood stoves Passive solar heating