Nitrous Acid Formation in an Experimental Exposure Chamber
Nitrous Acid Formation in an Experimental Exposure Chamber
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DOI：
10.1111/j.1600-0668.1993.t01-2-00004.x
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发表时间：
1993-06
期刊：
影响因子：
5.8
通讯作者：
M. Brauer;T. Rasmussen;S. Kjærgaard;J. Spengler
中科院分区：
文献类型：
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作者：
M. Brauer;T. Rasmussen;S. Kjærgaard;J. Spengler
反应性室内化学很少被认为是在调查的健康影响暴露于室内污染物，虽然提高认识可能有助于减少暴露错误分类，以及确定以前未知的风险。亚硝酸（HONO），由NO2与水在室内表面上的非均相反应形成，可能是二氧化氮（NO2）健康效应研究中被忽视的重要混杂因素。HONO-NO2关系的理解是重要的，因为NO2的常规测量实际上测量包括HONO在内的许多氮氧化物。因此，我们研究了相对湿度，腔室停留时间，地毯表面的存在和人类受试者的存在下，生产的HONO的NO2注入到一个腔室的影响。增加室内相对湿度导致更大的HONO浓度在一个给定的NO2水平。在80%相对湿度下，HONO浓度为NO2浓度的11%。增加在腔室中的停留时间增加了HONO水平，在20分钟和120分钟的停留时间之间HONO水平增加了五倍。羊毛地毯在腔室中的存在下，没有发现显着影响的HONO生产率，虽然NO2衰减率增加。当人类受试者出现在室内时，HONO浓度降低了在室内没有受试者的类似条件下存在的水平的50%。根据我们的研究结果，我们认为，未来的调查NO2的健康影响和室内空气质量必须认识到室内化学的重要性，特别是，HONO浓度升高的可能性，这将干扰NO2的测量和潜在的混淆调查的浓度-效果关系。同样，在评估暴露环境中其他潜在有毒含氮化合物的存在和重要性之前，应谨慎看待先前证明健康终点与NO2暴露之间关系的研究。
Reactive indoor chemistry has seldom been considered in investigations of the health effects of exposure to indoor contaminants although improved understanding may help to reduce exposure misclassification as well as identify previously unknown exposures. Nitrous acid (HONO), formed from the heterogeneous reaction of NO2 with water on indoor surfaces, may be a neglected and important confounder in studies of nitrogen dioxide (NO2) health effects. The understanding of HONO – NO2 relationships is important since conventional measurements of NO2 actually measure a number of nitrogen oxides including HONO. Accordingly, we examined the effects of relative humidity, chamber residence time, the presence of carpeted sufaces and the presence of human subjects on the production of HONO following the injection of NO2 into a chamber. Increasing chamber relative humidity led to greater HONO concentrations at a given NO2 level. At 80% relative humidity, HONO concentrations were 11% of the NO2 concentration. Increased residence time in the chamber increased HONO levels, with a five-fold increase in HONO levels between 20 minute and 120 minute residence times. The presence of wool carpets in the chamber was not found to affect significantly the HONO production rates, although NO2 decay rates were increased. When human subjects were present in the chamber, HONO concentrations decreased by as much as 50% of the levels present under similar conditions with no subjects in the chamber. In light of our results we argue that future investigations of NO2 health effects and indoor air quality must recognize the importance of indoor chemistry, and in particular, the likelihood of elevated concentrations of HONO which will interfere with NO2 measurements and potentially confound the investigation of concentration-effect relationships. Similarly, previous studies demonstrating a relationship between health endpoints and NO2 exposure should be viewed with caution until the presence and importance of other potentially toxic nitrogenous compounds in the exposure environment are evaluated.