Assessing the Impact of a Wood Stove Replacement Program on Air Quality and Children’s Health

EPA Grant Number: R834677C162
Subproject: this is subproject number 162 , established and managed by the Center Director under grant R834677
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Health Effects Institute (2010 — 2015)
Center Director: Greenbaum, Daniel S.
Title: Assessing the Impact of a Wood Stove Replacement Program on Air Quality and Children’s Health
Investigators: Noonan, Curtis W
Institution: Health Effects Institute (HEI)
EPA Project Officer: Hunt, Sherri
Project Period: April 1, 2010 through March 31, 2015
RFA: Health Effects Institute (2010) RFA Text |  Recipients Lists
Research Category: Health Effects , Air


Recent decades have seen substantial gains in air quality in the United States and Western Europe, with downward trends in concentrations of several major pollutants, including particulate matter (PM). These gains have been achieved largely through increasingly stringent air quality regulations and control measures. However, it is important to verify that regulations to improve air quality have indeed resulted in improved air quality and health.

The study led by Dr. Curtis W. Noonan evaluated a relatively large-scale program to replace about 1200 older, more polluting wood stoves with new, less polluting stoves in a rural mountain community (Libby, Montana), where residential wood combustion had been identifi ed as a major source of fi ne PM (PM2.5) during the heating season. Exposure to wood smoke is associated with increased respiratory symptoms in children and adults, decreased lung function in children, and increased emergency department visits and hospitalizations. In addition, wood smoke has been classifi ed as “probably carcinogenic in humans” by the International Agency for Research on Cancer. Noonan and colleagues hypothesized that the intervention would substantially reduce community exposure to PM2.5 derived from wood smoke, and thereby reduce children’s respiratory symptoms and illness-related school absences.


Noonan and colleagues collected air quality and health data during four consecutive winters starting in 2005, the fi rst year of the changeout program. The majority of changeouts took place during the second and third winters; the fourth winter constituted the postchangeout phase. Additional data were collected retrospectively, to cover two baseline winters before the start of the program.

The investigators measured PM2.5 and some of its components outdoors, inside schools during different seasons, and in about 20 homes (before and after stove changeout) during the winter. They focused on compounds suggested to be specifi c markers for wood smoke, such as levoglucosan, abietic acid, and dehydroabietic acid, and evaluated whether these compounds could be used to track source-specifi c changes in air quality inside homes as well as in ambient air.

In parallel, they tracked illness-related school absences in children and parent-reported respiratory symptoms. Changes in wintertime reporting of symptoms and variations in school absences were also evaluated in relation to changes in ambient PM2.5 concentrations in successive years.

Expected Results:

Ambient winter concentrations of PM2.5 gradually declined over the study period and were 30% lower in the fi nal winter after the changeout pro - gram (year 4) than in the baseline years. By the end of the study period, Libby was no longer out of compliance with the National Ambient Air Quality Standard for PM2.5.

Concentrations of levoglucosan, a fairly wellv alidated marker for wood smoke, were lower during the fi rst three winters of the program than during the baseline winters, but increased again during the fi nal winter. Concentrations of other potential markers, such as abietic acid and dehydroabietic acid, did not decrease in association with the changeout program. After stove changeout, indoor PM2.5 concentrations were lower in a majority of the homes sampled, although there was substantial variability within and between homes. At the elementary and middle schools, indoor concentrations of markers for wood smoke and PM2.5 were variable and not consistent with the timing of the changeout program.

Based on about 1700 surveys fi lled out by parents during the four years, there was a signifi cant reduction in childhood wheezing associated with lower winter ambient PM2.5 concentrations. The most robust associations were for itchy or watery eyes, sore throat, bronchitis, infl uenza, and throat infection. There were no differences in health outcomes (notably, wheezing) between children from homes with wood stoves and children from homes with other types of heating. School absence data showed that lower average ambient winter PM2.5 concentrations were associated with fewer illness-related absences among older students, but with higher absence rates among students in grades 1 through 4.

Relevant Websites: Exit

Main Center Abstract and Reports:

R834677    Health Effects Institute (2010 — 2015)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
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R834677C156 Concentrations of Air Toxics in Motor Vehicle-Dominated Environments
R834677C158 Air Toxics Exposure from Vehicle Emissions at a U.S. Border Crossing: Buffalo Peace Bridge Study
R834677C159 Role of Neprilysin in Airway Inflammation Induced by Diesel Exhaust Emissions
R834677C160 Personal and Ambient Exposures to Air Toxics in Camden, New Jersey
R834677C162 Assessing the Impact of a Wood Stove Replacement Program on Air Quality and Children’s Health
R834677C163 The London Low Emission Zone Baseline Study
R834677C165 Effects of Controlled Exposure to Diesel Exhaust in Allergic Asthmatic Individuals
R834677C168 Evaluating the Effects of Title IV of the 1990 Clean Air Act Amendments on Air Quality
R834677C172 Potential Air Toxics Hot Spots in Truck Terminals and Cabs
R834677C173 Detection and Characterization of Nanoparticles from Motor Vehicles
R834677C174 Cardiorespiratory Biomarker Responses in Healthy Young Adults to Drastic Air Quality Changes Surrounding the 2008 Beijing Olympics