Dales R, Chen L, Frescura A M, Liu L, Villeneuve P J
University of Ottawa, Ottawa, ON, Canada.
Eur Respir J. 2009 Aug;34(2):316-23. doi: 10.1183/09031936.00138908. Epub 2009 Feb 27.
Urban air pollution has been associated with morbidity but little information exists on how it affects diurnal variation of lung function in children with asthma. The purpose of this study was to investigate the acute effects of traffic-related pollution on lung function among children with asthma. We recorded morning and evening forced expiratory volume in 1 s (FEV(1)) for 28 consecutive days in 182 elementary schoolchildren with physician-diagnosed asthma, and monitored ambient hourly air pollution concentrations. An interquartile range (IQR) increase (6.0 microg m(-3)) in the previous 24-h (20:00 h to 20:00 h) mean concentration of fine particulate matter 2.5 microm in diameter (PM(2.5)) was associated with a 0.54% (95% confidence interval (CI) 0.06-1.02) decrease in bedtime FEV(1) (p = 0.027). This association persisted in two-pollutant models with ozone, nitrogen dioxide and sulphur dioxide. An IQR increase in mean daytime (08:00 h to 20:00 h) PM(2.5) of 6.5 microg m(-3) was associated with a 0.73% (95% CI 0.10-1.37) decrease in FEV(1) over the course of the day expressed as 100 x (FEV(1) bedtime - FEV(1) morning)/FEV(1) morning (p = 0.024). This study suggests that, in children with asthma, relatively low concentrations of urban air pollution worsen lung function over a short period of time, even within a day. Of the pollutants measured, PM(2.5 )appears to be the most important.
城市空气污染与发病率相关，但关于其如何影响哮喘儿童肺功能的昼夜变化，目前所知甚少。本研究旨在调查与交通相关的污染对哮喘儿童肺功能的急性影响。我们连续28天记录了182名经医生诊断为哮喘的小学生的早晚一秒用力呼气量（FEV(1)），并监测了每小时的环境空气污染浓度。直径2.5微米的细颗粒物（PM(2.5)）前24小时（20:00至20:00）平均浓度的四分位数间距（IQR）增加（6.0微克/立方米）与就寝时FEV(1)降低0.54%（95%置信区间（CI）0.06 - 1.02）相关（p = 0.027）。在包含臭氧、二氧化氮和二氧化硫的双污染物模型中，这种关联依然存在。白天（08:00至20:00）PM(2.5)平均浓度的IQR增加6.当以100×（FEV(1)就寝时 - FEV(1)早晨）/FEV(1)早晨表示一天中FEV(1)的变化时，5微克/立方米与FEV(1)降低0.73%（95%CI 0.10 - 1.37）相关（p = 0.024）。本研究表明，对于哮喘儿童，相对低浓度的城市空气污染在短时间内，甚至在一天内都会使肺功能恶化。在所测量的污染物中，PM(2.5)似乎是最重要的。
