CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Kolkata Zonal Centre, India.
Heritage Institute of Technology, Kolkata, India; School of Engineering, Brown University, Providence, RI, 02906, USA.
Environ Pollut. 2019 Apr;247:431-437. doi: 10.1016/j.envpol.2019.01.061. Epub 2019 Jan 19.
Roadside food-vending shanties using coal cookstoves may be an important source of carbon monoxide (CO) exposure in megacities in India. The shanties are often small, congested and poorly ventilated, and very little is known about the level of human exposure to CO. Here, we assessed the level of exposure to CO in 25 roadside food-vending shanties using coal cookstoves in Kolkata, India. Portable electrochemical CO monitors were used to measure CO concentrations during peak and non-peak customer-periods in closed (blocked from three sides) and semi-closed (blocked from two sides) shanties. Measurements were taken where customers sit indoor about 5-7 ft away from the cookstoves. The shanties' ventilation rates were measured using tracer gas concentration-decay technique. Levels of blood carboxyhaemoglobin (COHb) and exhaled CO were estimated using regression models. The 1-hr time weighted average (TWA) indoor CO exposure levels ranged from 7.8 to 18.1 ppm during peak-periods, and 0.7-3.1 ppm during non-peak-periods. The exposure levels during peak-periods exceeded the USEPA's reference limit of 9 ppm in all cases in the closed shanties, and in 71% of cases in the semi-closed shanties. The ventilation rates ranged from 5.5 to 23.4 and 14.8 to 32.5 cubic feet per minute (cfm) per person for the closed and semi-closed shanties, respectively, indicating poor ventilation in some shanties. There was significant variation (p = 0.01) in the level of indoor CO exposure between peak and non-peak periods, and between shanty types. The estimated levels of blood COHb during peak and non-peak hours were 0.78 ± 0.7% and 0.35 ± 0.07%, respectively, that were within the normal physiological values in non-smokers.
印度大城市路边摊贩使用煤炉做饭可能是一氧化碳（CO）暴露的一个重要来源。这些摊贩通常空间狭小、拥挤且通风不良，关于人类 CO 暴露水平的信息很少。在这里，我们评估了印度加尔各答 25 家路边摊贩使用煤炉做饭时 CO 暴露水平。在封闭（三面封闭）和半封闭（两面封闭）的棚屋内，使用便携式电化学 CO 监测器在高峰和非高峰客户时段测量 CO 浓度。在顾客坐在距离炉灶约 5-7 英尺的室内时进行测量。使用示踪气体浓度衰减技术测量棚屋的通风率。使用回归模型估计血液碳氧血红蛋白（COHb）和呼出 CO 的水平。在高峰时段，1 小时时间加权平均值（TWA）室内 CO 暴露水平范围为 7.8 至 18.1 ppm，在非高峰时段为 0.7 至 3.1 ppm。在所有封闭棚屋内，高峰时段的暴露水平都超过了 USEPA 的 9 ppm 参考限值，在 71%的半封闭棚屋内也是如此。通风率分别为 5.5 至 23.4 和 14.8 至 32.5 立方英尺每分钟（cfm）/人，表明一些棚屋的通风不良。在高峰和非高峰时段、棚屋类型之间，室内 CO 暴露水平存在显著差异（p=0.01）。在高峰和非高峰时段，血液 COHb 的估计水平分别为 0.78±0.7%和 0.35±0.07%，这在非吸烟者的正常生理范围内。
