ACUTE, SEVERE CARBON MONOXIDE AND PARTICULATE MATTER EXPOSURES AMONG SAUNA BATH (TEMASCAL) USERS IN THE WESTERN HIGHLANDS OF GUATEMALA

Abstract

ISEE-439 Introduction: We are currently working in the Guatemalan highlands on the first randomized intervention trial in air pollution history. In the stove intervention trial, about 500 households within 15 communities have been allocated randomly to either a control group (continue to cook over open fires and receive an improved stove--plancha-- at the end of the study period) or an intervention group (plancha built upon enrollment into the study). The principal outcome, acute lower respiratory infection, is being measured during weekly health surveillance by trained fieldworkers. A pilot study in August 2003 demonstrated that the household sauna bath (temascal) is also a significant source of woodsmoke exposure for about 86% of the study population. Nearly all household members, including newborn babies and young children, use the temascal regularly as their primary bathing method at least once per week. As the temascal is heated by a woodfire in poorly ventilated conditions, concentrations of wood smoke can sometimes be quite high. Methods: Twenty-three participants were surveyed about temascal use and seven temascals were monitored to quantify PM2.5 and CO levels. Breath CO measurements were taken from all participants before and after use of the temascal. Datalogging pollution monitors for CO and PM2.5 were placed inside the temascal during use. Results: Table 1. summarizes the results of breath measurements in this pilot study before and after using the temascal. Breath-CO (ppm), 23 Adults and Children over 10 yrs old; Before and After Temascal UsageTablePM2.5 averaged 2.3 mg/m3, with one-minute maximums recorded as high as 98.8 mg/m3 and one-minute CO levels in the temascals frequently exceeded 2000 ppm. Figures 1 and 2 present these results.FIGURE 1.: Comparison of one-minute indoor PM2.5 concentrations using Casella and MIE pDR light-scattering devices during one temascal event.FIGURE 2.: Continuous carbon monoxide levels (ppm) in four temascals.Discussion: The CO and PM2.5 levels found in this pilot study are astonishing, given that the U.S. legal 15-min ceiling for industrial workers is 200 ppm CO; for public exposure the one-hour limit is 35 ppm. The current EPA 24-hour standard for PM10 not to be exceeded more than 4 days a year, is 150 μg/m3. Even if this were the only daily PM exposure for these participants, their average exposure over a 24-hour period would be 49 μg/m3 PM2.5. For comparison with Table 1, a previous study in the same area among 87 women cooks found levels of after-cooking breath CO of 4.6 ppm (plancha, n=45) and 6.5 ppm (open fire, n=42). This source of exposure creates a significant risk of acute CO poisoning as well as adding substantially to chronic exposures. CO poisoning is often classified above 25% carboxyhemoglobin, (exhaled breath CO=150 ppm), a level we measured in 17% of the participants. Several women exiting the temascals were dizzy, one with a severe headache. In several cases, small children left the temascal asleep, a possible sign of moderate CO poisoning. We are currently planning a new investigation of these exposures among a wider sample, along with the development of a culturally appropriate, affordable cleaner-burning temascal fire.