Abstract Exposure to ambient air pollutants may significantly affect the incidence of respiratory symptoms and lung function in children. The present study examined the associations between exposure to ambient air pollutants and respiratory symptoms in children. In this cross-sectional study, 1070 children under the age of seven years were recruited from 61 day-care centers of Tehran in 2015. Initially, day-care centers were selected at a radius of 2 km from the air pollution monitoring stations, and subsequently all the children attending these day-care centers were interviewed. The data on the respiratory complaints of children were obtained by using the ATS questionnaire (ATS-DLD-78-C). Moreover, the annual average concentration of pollutants was calculated based on the time children spent at home and at the day-care center using the air pollution monitoring stations. Crude and adjusted logistic regression analysis was conducted. The findings indicated that ambient air SO2 and NO2 concentrations near home were associated with current asthma for 1 part per billion (ppb) increase with an OR of 1.20 (1.00–1.45) and 1.08 (1.01–1.15), respectively. The odds of developing persistent phlegm for each unit (ppm) of raise in the average annual concentration of CO in ambient air near home (OR 1.40; 1.09 to 1.81) increased as well. The daily mean concentration of PM2.5, PM10, and SO2 was higher than the limits provided in the World Health Organization (WHO) air quality guidelines (AQGS). Moreover, the prevalence of severe wheezing, asthma history, and bronchitis was higher in boys. Therefore, long-term exposure to ambient air pollutants such as SO2, NO2, and CO may be associated with an increase in current asthma and persistent phlegm in children.

中文翻译：

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德黑兰幼儿环境空气污染与呼吸道体征和症状之间的横断面关联

摘要 环境空气污染物暴露可能显着影响儿童呼吸道症状和肺功能的发生率。本研究调查了暴露于环境空气污染物与儿童呼吸道症状之间的关联。在这项横断面研究中，2015 年从德黑兰 61 家日托中心招募了 1070 名 7 岁以下儿童。随后，这些日托中心的所有儿童都接受了采访。使用ATS问卷（ATS-DLD-78-C）获取儿童呼吸主诉数据。而且，污染物的年平均浓度是根据儿童在家里和日托中心使用空气污染监测站的时间计算得出的。进行了粗略和调整后的逻辑回归分析。研究结果表明，家附近的环境空气 SO2 和 NO2 浓度与当前的哮喘相关，增加了十亿分之一 (ppb)，OR 分别为 1.20 (1.00–1.45) 和 1.08 (1.01–1.15)。家附近环境空气中 CO 年平均浓度（OR 1.40；1.09 至 1.81）每增加一个单位（ppm），产生持续性痰的几率也增加了。PM2.5、PM10和SO2日均浓度高于世界卫生组织（WHO）空气质量指南（AQGS）规定的限值。此外，有严重喘息、哮喘病史、男孩的支气管炎发病率更高。因此，长期暴露于 SO2、NO2 和 CO 等环境空气污染物可能与儿童当前哮喘和持续性痰的增加有关。