HONO, NO2, and asthma

The association between nitrogen dioxide (NO2) and asthma has been investigated. However, conventional NO2 assays measure nitrous acid (HONO) as NO2. In this trial study, we assessed exposure to indoor HONO and some air pollutants in pediatric asthma patients and examined the association between exposure and asthma symptoms. Indoor HONO and nitric oxide (NO), which are primarily generated by the combustion of certain substances, were significantly associated with asthma attacks in 2010 and 2010-2012. Outdoor NO2 was significantly associated with asthma attacks in 2012 and 2010-2012. In 2010, indoor HONO was strongly correlated with indoor NO than with outdoor NO2. Conversely, in 2012, indoor HONO was strongly correlated with outdoor NO2 and NO than with indoor NO2 and NO. Our results highlight the need for further epidemiological studies of the association between HONO and asthma symptoms using multivariate analyses to examine the role of NO2 in asthma symptoms. This study is a trial epidemiological study targeting five pediatric asthma patients per year (2010–2012) with daily self-reported asthma symptoms. Indoor HONO was collected weekly by active sampling at the subjects’ homes. Indoor NO2, NO, and O3 samples were collected weekly by passive sampling at the subjects’ homes. We used data from the Kishiwada Central Park monitoring station. The weekly concentrations of outdoor pollutants for each subject were calculated from hourly data of the monitoring station according to indoor sampling periods.目前已有研究探讨了二氧化氮（nitrogen dioxide, NO₂）与哮喘之间的关联。然而，常规的NO₂检测方法会将亚硝酸（nitrous acid, HONO）误计为NO₂。本试验性研究针对儿科哮喘患者，评估了其室内亚硝酸及部分空气污染物的暴露情况，并分析了暴露水平与哮喘症状之间的关联。室内亚硝酸与一氧化氮（nitric oxide, NO）主要由特定物质燃烧产生，在2010年及2010-2012年期间，二者与哮喘发作均呈显著关联。室外二氧化氮则在2012年及2010-2012年期间与哮喘发作呈显著关联。2010年，室内亚硝酸与室内一氧化氮的相关性强于其与室外二氧化氮的相关性；反之，2012年室内亚硝酸与室外二氧化氮、一氧化氮的相关性强于其与室内二氧化氮及一氧化氮的相关性。本研究结果表明，需开展更多采用多变量分析的流行病学研究，以厘清二氧化氮在哮喘症状发生中的作用，并进一步探讨亚硝酸与哮喘症状之间的关联。本试验性流行病学研究的研究对象为2010-2012年期间每年纳入的5名儿科哮喘患者，所有受试者每日自行报告哮喘症状。研究人员通过主动采样法，每周在受试者家中采集室内亚硝酸样本；同时采用被动采样法，每周在受试者家中采集室内二氧化氮、一氧化氮及臭氧（ozone, O₃）样本。本研究使用岸和田中央公园监测站的监测数据，根据受试者的室内采样时段，由该监测站的小时浓度数据计算得到每名受试者对应的室外污染物周均浓度。