10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Indoor Aerosols from Home Heating in the Navajo Nation: Sources, Health Effects, and Control
LUPITA MONTOYA, Wyatt Champion, Paul A. Solomon, Kathleen Stewart, Perry Charley, University of Colorado Boulder
Abstract Number: 801 Working Group: Indoor Aerosols
Abstract A previous study determined that using wood and coal for indoor heating in poorly-maintained stoves likely leads to indoor air pollution and negative health effects in the Navajo Nation (NN) (Bunnell et al., 2010). Emissions from residential wood/coal combustion include fine particulate matter (PM2.5), which has been linked to respiratory and cardiovascular disease. They suggested that changing indoor heating behaviors and improving heating stove quality would lead to improvements in indoor air quality (IAQ) and health in this community.
Since IAQ in Native Nations in the U.S. has received very little attention, a series of studies were conducted in response to Bunnell’s recommendations. First, the In-Home Heating Alternatives Project (IHAP) assessed in-home heating options for residents of the NN (Champion et al., 2017a). This mixed-methods analysis integrated perception, culture, and technical assessments to provide recommendations for a stove replacement program appropriate for this community. Second, controlled experiments were conducted at the University of Colorado Boulder to evaluate emission factors in terms of mass (mEF) and energy (eEF) for PM2.5, organic and elemental carbon (OC, EC), CO and CO2 for 2 woods and 2 coals commonly used in the NN (Champion et al., 2017b). A third study evaluated potential oxidative and inflammatory effects of PM2.5 generated during the combustion of these 4 fuels utilizing an old stove representative of those used in the NN (Li et al., 2018).
Results from IHAP determined that improved stoves, replacement stoves and passive solar heating were viewed most positively by the Navajo; however, replacement stoves showed the best combined results. In particular, replacement stoves that can combust both wood and coal were recommended. IHAP helped uncover areas where community perception, culture, and the technical analyses align and where there are discrepancies necessitating increased dialogue regarding healthier heating methods. It is necessary that community cultural experts (e.g., Diné Policy Institute) conduct thorough cultural assessments to achieve effective integration of culture and science.
The second study determined emission factors for PM2.5, OC, EC, CO and CO2 for the 4 fuels studied. Results showed that Ponderosa Pine had the lowest mEF and eEF for PM2.5, OC, CO and CO2. Ponderosa Pine also produced about 50% fewer PM2.5 emissions than Utah Juniper during the ignition and warm-up phase. Overall, coal compared to wood produced significantly higher emissions on both mass and energy bases.
The third study determined that Ponderosa Pine wood consistently had the strongest oxidative stress and inflammatory effects. PM components, i.e. low-volatility OC, EC, and soluble Cu, Ni and K were positively correlated with the cellular responses. These findings suggest that PM2.5 emitted from combustion of wood and coal commonly used by Navajo residents may negatively impact the health of this community.
Together, these studies informed a heating stove intervention in the NN that includes the option of a new USEPA-certified dual (wood/coal) heating stove, designed specifically for the Navajo. We propose that the framework used for this study may be applicable to other Native American Nations, such as the nearby Hopi Nation, where climate conditions and coal use are similar to those of the NN.
References [1] Bunnell J.E., Garcia L.V., Furst J.M., Lerch H., Olea R.A., Suitt S.E., Kolker A. 2010. Journal of Environmenal and Public Health, 260525. [2] Champion W.M., Charley P.H., Klein B., Stewart K., Solomon P.A., Montoya L.D. 2017a. Science of the Total Environment, 580:297-306. [3] Champion W.M., Connors L., Montoya L.D. 2017b. Journal of the Air and Waste Management Association, 67(9): 1020-1035. [4] Li N., Champion W.M., Imam J., Sidhu D., Salazar J.R., Majestic B.J., Montoya L.D. 2018. Under revision, Atmospheric Environment.