Assessment of a Woodstove Changeout Program on PM2.5 Levels in Keene, New Hampshire, U.S.A.

In local airsheds, wood smoke from residential woodstoves is a major source of PM2.5 pollution. Exposure to PM2.5 can cause a variety of health problems and complications. Communities situated in valleys that experience cold winters are especially susceptible to poor air quality during inversion events on calm winter nights. Keene, New Hampshire, USA is one such community where the widespread use of outdated residential woodstoves frequently resulted in PM2.5 exceeding national standards. Seeking to improve air quality, the City of Keene partnered with the New Hampshire Department of Environmental Services from 2009-2010 to facilitate a woodstove changeout program which replaced 86 inefficient woodstoves with newer or alternate heating appliances. Despite the fact that many U.S. communities have enacted similar programs, research on their effectiveness is limited. This research assessed Keene’s program and determined that Keene has experienced a significant reduction in PM2.5 on calm winter nights. When winds are below 2 miles per hour (3.22 kilometers per hour), PM2.5 dropped 7% to 52% (1.28 to 7.30 µg/m3) after the woodstove changeout; a mean decrease of 23%. It therefore appears that Keene’s woodstove changeout program successfully improved air quality on the nights that are most likely to violate national air quality standards. This provides evidence that such programs can be an effective means to moderating the effects of wood heating in communities susceptible to inversions.