Department of Statistics, Fluminense Federal University (GET/UFF), Niterói, Brazil.
Environ Res. 2012 Aug;117:27-35. doi: 10.1016/j.envres.2012.05.006. Epub 2012 Jun 8.
Exposure to high levels of particulate matter with an aerodynamic diameter less than 2.5 μm (PM(2.5)) resulting from biomass burning is frequent in the subequatorial Amazon region.
To investigate whether or not current exposure to PM(2.5) in the Brazilian Amazon has adverse effects on the daily peak expiratory flow (PEF) of schoolchildren.
The study design consisted of a panel comprising 309 children aged 6 to 15 years from the same school. PEF was measured daily, except weekends and holidays, from August to December 2006. Each child contributed to the study up to 67 daily measurements. All together there were 19115 PEF measures. Participation rate was 90%. Daily measurements of PM(2.5), temperature, and humidity as well as passive smoking, and subject features were regarded in the statistical analysis. Various exposures of PM(2.5) were considered throughout the analysis, among them 24-hour, 12-hour, 6-hour, and 5-hour means. To account for subject responses to confounders, mixed effects models were applied. The effects were evaluated considering air pollution levels on the current day or at 1- or 2-day lags and the averages of 0-1-day lags, 1-2-day lags and 0-, 1-, and 2-day lags.
The 24-hour PM(2.5) means ranged from 6.39 to 99.91 μg/m(3). The adjusted models for the entire group of children revealed adverse effects. For instance, for an increase of 10 μg/m(3) in PM(2.5,) the reduction in the PEF average varied between 0.26 l/min (95% Confidence Interval (CI): -0.49; -0.04) and 0.38 l/min (95% CI: -0.71; -0.04). Restricted to the subgroup of non-asthmatic children, classified as such according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, there was a reduction in the PEF ranging from 0.38 l/min (95% CI: -0.63; -0.13) to 0.53 l/min (95% CI: -0.90; -0.16) for an increase of 10 μg/m(3) in PM(2.5). There was no significant effect in the asthmatic group. When stratified by time of the day children were at school, the concurrent effects of air pollution on PEF were not significant, whereas the 6-hour exposure from 0 am to 5:30 am was significant for both morning and afternoon groups. Finally, the 24-hour mean lagged effect was only significant for the afternoon group of children. For an increase of 10 μg/m(3) in PM(2.5,) there was a reduction in the PEF that ranged from 0.41 l/min (95% CI: -0.76; -0.06) to 0.49 l/min (95% CI: -0.91; -0.07).
Exposure to current levels of PM(2.5) in the Brazilian Amazon was associated with reductions in the lung function of schoolchildren. The adverse effects were more consistent in non-asthmatic children and with respect to the 6-hour mean from 0 am to 5.30 am.
在赤道亚马逊地区，生物质燃烧导致的小于 2.5μm 的空气动力学直径的颗粒物（PM（2.5））的高水平暴露很常见。
研究当前亚马逊地区巴西的 PM（2.5）暴露是否对小学生的日常呼气峰值流量（PEF）有不良影响。
该研究设计包括一个由 309 名年龄在 6 至 15 岁的来自同一所学校的儿童组成的小组。除周末和节假日外，从 2006 年 8 月至 12 月，每天测量 PEF。每个孩子每天最多可贡献 67 次测量值。共有 19115 次 PEF 测量值。参与率为 90%。在统计分析中考虑了 PM（2.5）、温度、湿度以及被动吸烟和受试者特征的日常测量值。在整个分析过程中考虑了各种 PM（2.5）暴露，包括 24 小时、12 小时、6 小时和 5 小时均值。为了说明对混杂因素的响应，应用了混合效应模型。考虑了当天或前 1-2 天的空气污染水平以及 0-1 天、1-2 天和 0、1 和 2 天的平均值的影响。
24 小时 PM（2.5）平均值范围为 6.39 至 99.91μg/m3。对于整个儿童组的调整模型显示出了不良影响。例如，PM（2.5）增加 10μg/m3，PEF 平均值的降低幅度在 0.26 l/min（95%置信区间（CI）：-0.49；-0.04）和 0.38 l/min（95% CI：-0.71；-0.04）之间。对于非哮喘儿童亚组（根据国际儿童哮喘和过敏研究（ISAAC）问卷进行分类），限制在该亚组内，PM（2.5）增加 10μg/m3，PEF 的降低幅度在 0.38 l/min（95% CI：-0.63；-0.13）和 0.53 l/min（95% CI：-0.90；-0.16）之间。在哮喘组中没有显著的影响。当按儿童在学校的时间进行分层时，空气污染对 PEF 的并发影响并不显著，而从 0 点到 5 点 30 分的 6 小时暴露对上午和下午两组都有显著影响。最后，24 小时平均滞后效应仅对下午组的儿童有显著影响。PM（2.5）增加 10μg/m3，PEF 降低幅度在 0.41 l/min（95% CI：-0.76；-0.06）和 0.49 l/min（95% CI：-0.91；-0.07）之间。
巴西亚马逊地区当前水平的 PM（2.5）暴露与小学生肺功能下降有关。在非哮喘儿童中，这种不良影响更为一致，而且在 0 点到 5.30 点的 6 小时平均值上也是如此。
