Lam Nick, Nicas Mark, Ruiz-Mercado Ilse, Thompson Lisa M, Romero Carolina, Smith Kirk R
Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, USA.
J Environ Monit. 2011 Aug;13(8):2172-81. doi: 10.1039/c1em10172b. Epub 2011 Jun 20.
The use of wood-fired steam baths, or temazcales, is a potentially dangerous source of CO exposure in Guatemalan Highland communities where adults and children use them regularly for bathing, relaxation, and healing purposes. Physical characteristics of children predispose them to absorb CO faster than adults, placing them at greater exposure and health risks. Efforts to quantify temazcal exposures across all age groups, however, have been hampered by the limitations in exposure measurement methods. In this pilot study we measured COHb levels in children and adults following use of the temazcal using three field-based, non-invasive CO measurement methods: CO-oximetry, exhaled breath, and by estimation of COHb using micro-environmental concentrations and time diaries. We then performed a brief comparison of methods. Average CO concentrations measured during temazcal use were 661 ± 503 ppm, approximately 10 times the 15 min WHO guideline. Average COHb levels for all participants ranged from 12-14% (max of 30%, min 2%), depending on the method. COHb levels measured in children were not significantly different from adults despite the fact that they spent 66% less time exposed. COHb measured by CO-oximetry and exhaled breath had good agreement, but precision of the former was affected substantially by random instrument error. The version of the field CO-oximeter device used in this pilot could be useful in screening for acute CO exposure events in children but may lack the precision for monitoring the burden from less extreme, but more day-to-day CO exposures (e.g. indoor solid fuel use). In urban settings, health effects in children and adults have been associated with chronic exposure to ambient CO concentrations much lower than measured in this study. Future research should focus on reducing exposure from temazcales through culturally appropriate modifications to their design and practices, and targeted efforts to educate communities on the health risks they pose and actions they can take to reduce this risk.
在危地马拉高地社区，使用燃木蒸汽浴（或称temazcales）是一氧化碳暴露的潜在危险来源，当地的成人和儿童经常使用它们来洗澡、放松和治疗。儿童的身体特征使他们比成人更快地吸收一氧化碳，从而使他们面临更大的暴露风险和健康风险。然而，由于暴露测量方法的局限性，对所有年龄组的temazcal暴露进行量化的努力受到了阻碍。在这项试点研究中，我们使用三种基于现场的非侵入性一氧化碳测量方法，测量了儿童和成人使用temazcal后的碳氧血红蛋白（COHb）水平：一氧化碳血氧测定法、呼出气体法，以及通过微环境浓度和时间日记估算COHb。然后，我们对这些方法进行了简要比较。在使用temazcal期间测得的平均一氧化碳浓度为661±503 ppm，约为世界卫生组织15分钟指导值的10倍。所有参与者的平均COHb水平在12% - 14%之间（最高30%，最低2%），具体取决于测量方法。尽管儿童暴露时间比成人少66%，但测得的儿童COHb水平与成人并无显著差异。通过一氧化碳血氧测定法和呼出气体法测得的COHb结果具有良好的一致性，但前者的精度受到随机仪器误差的显著影响。本试点研究中使用的现场一氧化碳血氧测定仪版本可用于筛查儿童急性一氧化碳暴露事件，但可能缺乏监测不太极端但更日常的一氧化碳暴露（例如室内使用固体燃料）负担的精度。在城市环境中，儿童和成人的健康影响与长期暴露于比本研究中测得的浓度低得多的环境一氧化碳浓度有关。未来的研究应侧重于通过对temazcales的设计和使用方式进行符合文化习惯的改进，以及有针对性地开展工作，向社区宣传它们所带来的健康风险以及可以采取的降低风险的行动，来减少temazcales造成的暴露。
