Room chamber assessment of the pollutant emission properties of (nominally) low-emission unflued gas heaters

Abstract

Unflued gas heaters have been popular as primary heating sources in Australian homes for many years due to their ease of installation and energy efficiency, with approximately 600,000 now installed in housing and schools. However, with concerns over potential health impacts to occupants, manufacturers have reduced the nitrogen dioxide emissions from unflued gas heaters in Australia over recent years. They have done so with a target level for nitrogen dioxide in indoor air of 300 p.p.b. This is somewhat higher than the ambient air (and WHO) guideline of 110 p.p.b. Several studies of child respiratory health show an impact of unflued gas combustion products. A full characterization of the combustion products is needed under conditions that simulate heater operation in practice-this study was undertaken to provide such characterization. Key findings are that the focus needs to be on total gas emissions (not just nitrogen dioxide), and that heater installation can be very sensitive to small faults which lead to very high levels of toxic pollutants. These findings have influenced current government proposals for emission limits for these heaters.

Risk factors for mold in housing: a national survey

“…Indeed, as these heaters produce large amounts of water vapor as part of their normal operation, it is plausible that they do contribute to humidity and dampness in houses. This type of heating is also known to produce a variety of toxic emissions (Brown et al., 2004) and a randomized controlled trial of unflued gas heater replacement in schools has reported improvements in the respiratory health of asthmatic schoolchildren (Pilotto et al., 2004). For these reasons the high usage rates of this type of heating in New Zealand is of concern from a public health perspective and requires further study and policy responses.…”

Catalytic oxidation of benzene using DBD corona discharges

“…Recently, the abatement technologies for controlling hazardous air pollutants, such as volatile organic compounds (VOCs) in indoor air [1][2][3], are becoming more and more important both for considering of human health and global warming. Especially, high concentration VOCs from some sources such as paints, chemical plants, and printing industries, are of high risk and their emission should be reduced.…”

Respiratory Health Effects of Exposure to Low-NO x Unflued Gas Heaters in the Classroom: A Double-Blind, Cluster-Randomized, Crossover Study

“…There has been one published report of a laboratory-based assessment of emissions from low-NO x unflued gas heaters (Brown et al 2004). This study showed that the five tested heaters did emit NO 2 and, in some cases, formaldehyde and carbon monoxide.…”