Peak Indoor NO2 Concentration and Respiratory Outcomes in Children with Asthma

描述(申请人提供)：哮喘是儿童中最常见的慢性疾病，目前的管理重点是使用药物控制和避免加剧疾病的因素。暴露在室外和室内空气污染物中，包括燃烧的副产品二氧化氮(NO2)，与哮喘发病率恶化有关。最近的证据表明，环境中NO2的每小时峰值浓度与哮喘患者急诊科就诊和住院人数的增加有关，这促使EPA修改了环境NO2的NAAQS标准，将每小时浓度限制在100 ppb。该研究小组成员的调查表明，在巴尔的摩哮喘儿童中，室内二氧化氮平均浓度较高与呼吸道症状恶化之间存在关联。燃气灶等燃烧源是室内环境所特有的，会产生NO2的短期峰值浓度，而这些浓度在几天的平均浓度中是无法捕获的。然而，室内NO2峰值浓度对哮喘健康的影响尚不清楚。我们假设，这些峰值浓度会导致更严重的哮喘，与每日或每周平均的NO2浓度相比，与呼吸健康的联系更强。为了研究短期和峰值NO2浓度对哮喘儿童哮喘症状和肺功能的影响，我们建议增加对室内NO2浓度的持续监测，并对已经登记在现有研究-城市环境哮喘-饮食研究的儿童哮喘中心的一个子组(n=40)的哮喘儿童进行全面的时间活动日记管理。这项提议有三个新颖的目标。首先，为了确定室内NO2日最高浓度是否与市中心儿童哮喘发病率有关，我们将研究室内NO2日最高浓度对哮喘儿童肺功能和症状的影响。其次，为了确定室内每日平均NO2浓度是否与市中心儿童哮喘发病率有关，我们将研究24小时平均NO2浓度与哮喘结果之间的关系。最后，我们将使用详细的时间活动日记来确定Indoo来源对市中心家庭NO2浓度短期变化的相对贡献。这项研究的结果将确定NO2浓度升高的潜在来源，并告知未来的干预研究是否可以针对NO2浓度的短期增加，这可能比旨在持续减少NO2的策略更具成本效益和可行性。 公共卫生相关性：哮喘是一种常见的儿童疾病，室内空气污染物包括二氧化氮(NO2)会加剧哮喘，二氧化氮是由燃气炉使用等燃烧过程产生的。我们感兴趣的是量化与家庭使用燃烧源有关的NO2峰值和每日浓度，并确定这些浓度是否与哮喘儿童的肺功能和症状恶化有关。如果发现NO2的峰值浓度是儿童哮喘症状的主要驱动因素，并且这些水平与使用室内来源的NO2有关，那么改善家庭环境以减少这些使用期间的暴露可能是一个可行的干预措施，以减少NO2对哮喘儿童的有害影响。

DESCRIPTION (provided by applicant): Asthma is the most common chronic disease among children and current management focuses on control using medications and avoidance of factors that exacerbate the disease. Exposure to outdoor and indoor air pollutants, including nitrogen dioxide (NO2), which is a byproduct of combustion, has been associated with worsening asthma morbidity. Recent evidence suggests that hourly peak concentrations of ambient NO2 are associated with increases in emergency department visits and hospitalizations in people with asthma, prompting the EPA to modify the NAAQS standard for ambient NO2 to include an hourly concentration limit of 100ppb. Investigations by members of this research group have shown an association between higher mean concentrations of indoor NO2 and worsening respiratory symptoms in Baltimore children with asthma. Combustion sources, such as gas stoves, are unique to the indoor environment and produce short-term peak concentrations of NO2 that are not captured in mean concentrations measured over several days. However, the effect of peak indoor NO2 concentrations on asthma health is unknown. We hypothesize that these peak concentrations contribute to worse asthma and are more strongly linked to respiratory health than daily or weekly averages of NO2 concentrations. To study the effect of short-term and peak NO2 concentrations on asthma symptoms and lung function in children with asthma, we propose to add continuous monitoring of indoor NO2 concentrations and the administration of comprehensive time activity diaries in a subgroup (n=40) of children with asthma already enrolled in an existing study, The Center for Childhood Asthma in the Urban Environment ASTHMA-DIET Study. This proposal has three novel aims. First, to determine whether daily peak indoor NO2 concentrations are associated with asthma morbidity in inner city children, we will examine the effect of daily peak indoor NO2 concentrations on lung function and symptoms in children with asthma. Second, to determine whether daily average indoor NO2 concentrations are associated with asthma morbidity in inner city children, we will examine the relationship between 24-hour average NO2 concentrations and asthma outcomes. Finally, we will use detailed time activity diaries to determine the relative contribution of indoo sources to short-term variability in NO2 concentrations in inner-city homes. Results from this study will identify potential sources of elevated NO2 concentrations and inform whether future intervention studies can be directed at short-term increases in NO2 concentrations, which may be more cost-effective and feasible than strategies aimed at continuous NO2 reduction. PUBLIC HEALTH RELEVANCE: Asthma is a common disease of childhood and can be exacerbated by indoor air pollutants, including nitrogen dioxide (NO2), which is produced by combustive processes such as gas stove use. We are interested in quantifying peak and daily concentrations of NO2 in relation to use of combustion sources in the home, and to determine if these concentrations are associated with worsening lung function and symptoms in children with asthma. If peak concentrations of NO2 are found to be the predominant driver of asthma symptoms in children, and these levels are associated with use of an indoor source of NO2, modifying the home environment to reduce exposure during these periods of use may be a feasible intervention to reduce the harmful effect of NO2 on children with asthma.