Using exhaled carbon monoxide and carboxyhemoglobin to evaluate the effectiveness of a chimney stove model in Peru.

BACKGROUND: Measurement of biological indicators of physiological change may be useful in evaluating the effectiveness of stove models, which are intended to reduce indoor smoke exposure and potential health effects. OBJECTIVES: We examined changes in exhaled carbon monoxide (CO), percentage carboxy-hemoglobin, and total hemoglobin in response to the installation of a chimney stove model by the Juntos National Program in Huayatan, Peru in 2008. METHODS: Biomarkers were measured in a convenience sample comprising 35 women who met requirements for participation, and were measured before and three weeks after installation of a chimney stove. The relationships between exposure to indoor smoke and biomarker measurements were also analyzed using simple linear regression models. RESULTS: Exhaled CO reduced from 6.71 ppm (95% CI 5.84-7.71) to 3.14 ppm (95% CI 2.77-3.66) three weeks after stove installation (P < 0.001) while % COHb reduced from 1.76% (95% CI 1.62-1.91) to 1.18% (95% CI 1.12-1.25; P < 0.001). Changes in exhaled CO and % COHb from pre- to post-chimney stove installation were not correlated with corresponding changes in exposure to CO and PM2.5 even though the exposures also reduced after stove installation. CONCLUSION: Exhaled CO and % COHb both showed improvement with reduction in concentration after the installation of the chimney cook stoves, indicating a positive physiological response subsequent to the intervention.

Testing the effectiveness of two improved cookstove interventions in the Santiago de Chuco Province of Peru.

90% of people residing in rural areas of less-developed countries rely on coal and biomass fuels for heating and cooking, leading to high exposures to the products of incomplete combustion. Three Andean communities within the Santiago de Chuco province of Peru received two different models of improved cookstoves. The impact of these stoves in reducing personal exposures and kitchen concentrations of fine particulate matter (PM(2.5)) and carbon monoxide (CO) was evaluated separately in 64 homes (32 with each stove model) using air monitoring equipment. In the community receiving stove 1, baseline aggregate 48-h personal exposure (n=27) and kitchen concentrations (n=26) of PM(2.5) were 116.4 and 207.3µg/m(3), respectively, and 48-h personal (n=25) and kitchen (n=25) CO levels were 1.2 and 3.6ppm. After introducing the new stove to this community, those exposures reduced to 68.4 and 84.7µg/m(3), and 0.4 and 0.8ppm, representing reductions of 41.3%, 59.2%, 69.6% and 77.7% respectively. In the two communities receiving stove 2, corresponding levels were 126.3µg/m(3) (n=18), 173.4µg/m(3) (n=19), 0.9ppm (n=19), and 2.6ppm (n=17) before the installation of the stoves, and they reduced to 58.3, 51.1µg/m(3) and 0.6, 1.0ppm. Overall, homes receiving stove 2 saw reductions of 53.8, 70.5, 25.8 and 63.6%. All values are statistically significant (p<0.05) with the exception of personal CO reductions in the stove 2 group. Both stoves markedly reduce both kitchen and personal levels of wood smoke exposure, which we believe has the potential to improve health and quality of life.