Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York 10987-5007, USA.
Environ Health Perspect. 2011 Apr;119(4):559-65. doi: 10.1289/ehp.1002653. Epub 2011 Jan 7.
Previous studies have reported relationships between adverse respiratory health outcomes and residential proximity to traffic pollution, but have not shown this at a personal exposure level.
We compared, among inner-city children with asthma, the associations of adverse asthma outcome incidences with increased personal exposure to particulate matter mass ≤ 2.5 μm in aerodynamic diameter (PM(2.5)) air pollution versus the diesel-related carbonaceous fraction of PM2.5.
Daily 24-hr personal samples of PM(2.5), including the elemental carbon (EC) fraction, were collected for 40 fifth-grade children with asthma at four South Bronx schools (10 children per school) during approximately 1 month each. Spirometry and symptom scores were recorded several times daily during weekdays.
We found elevated same-day relative risks of wheeze [1.45; 95% confidence interval (CI), 1.03-2.04)], shortness of breath (1.41; 95% CI, 1.01-1.99), and total symptoms (1.30; 95% CI, 1.04-1.62) with an increase in personal EC, but not with personal PM(2.5) mass. We found increased risk of cough, wheeze, and total symptoms with increased 1-day lag and 2-day average personal and school-site EC. We found no significant associations with school-site PM(2.5) mass or sulfur. The EC effect estimate was robust to addition of gaseous pollutants.
Adverse health associations were strongest with personal measures of EC exposure, suggesting that the diesel "soot" fraction of PM(2.5) is most responsible for pollution-related asthma exacerbations among children living near roadways. Studies that rely on exposure to PM mass may underestimate PM health impacts.
先前的研究报告了呼吸道健康不良后果与居住临近交通污染之间的关系，但没有在个人暴露水平上显示这一点。
我们比较了城市内哮喘儿童中，个人接触细颗粒物质量≤2.5μm（PM2.5）空气污染与 PM2.5 中与柴油机相关的碳质部分的增加与不良哮喘后果发生率之间的关联。
在大约 1 个月的时间里，在南布朗克斯的四所学校（每所学校 10 名儿童）中，每天对 40 名五年级哮喘儿童进行 24 小时个人 PM2.5 采样，包括元素碳（EC）部分。在工作日期间，每天多次记录肺活量测定和症状评分。
我们发现，EC 个人暴露量的增加与同日内喘息（1.45；95%置信区间（CI），1.03-2.04）、呼吸急促（1.41；95%CI，1.01-1.99）和总症状（1.30；95%CI，1.04-1.62）的比值风险升高有关，但与 PM2.5 质量无关。我们发现，随着个人和学校地点 EC 的 1 天滞后和 2 天平均暴露量的增加，咳嗽、喘息和总症状的风险增加。我们没有发现与学校地点 PM2.5 质量或硫显著相关。EC 效应估计值在加入气态污染物后仍然稳健。
与个人 EC 暴露水平相关的健康不良关联最强，这表明 PM2.5 中柴油机“烟尘”部分是导致居住在道路附近的儿童哮喘恶化的主要原因。依赖 PM 质量进行的研究可能低估了 PM 对健康的影响。
