Ostro B
Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Berkeley 94704, USA.
Environ Res. 1995 Aug;70(2):98-104. doi: 10.1006/enrs.1995.1053.
Several epidemiologic studies have reported associations between respiratory disease and particulate matter less than 2.5 microns in diameter (PM2.5) or fine particles. However, since daily fine particulate data from ambient monitors are seldom available, many studies have used estimates of PM2.5 based on visual range observed at local airports. This paper examines the impact of visibility-based estimates of PM2.5 on mortality from 1980 through 1986 in San Bernardino and Riverside Counties, located in the Los Angeles metropolitan area. Multiple regression analysis was used to isolate the effects of estimated fine particles on mortality while controlling for covariates, including season, day of week, maximum temperature, and dew point. The results are dependent on season. During the summer quarters, there was a small but statistically significant association of estimated fine particles with both total mortality (RR = 1.03, 95% CI = 1.00-1.05, evaluated at the mean PM2.5 value of 32.5 microg/m3) and respiratory-specific mortality. However, for the year taken as a whole, estimated fine particles were not associated with mortality (RR = 1.00; 95% CI = 0.99-1.02). The use of estimated fine particles introduces additional measurement error into the analysis. During the summer quarters, an effect of ozone on mortality was also detected, but this association could be due to confounding with temperature. Sensitivity analysis indicated that the fine particulate association found during the summer quarters was robust to alternative estimates deriving fine particles from visual range, alternative regression specifications, functional forms, and exposure averaging times. These findings are consistent with another recent study of mortality in Los Angeles County and add to the other findings of associations between particulate matter and various respiratory diseases outcomes.
多项流行病学研究报告了呼吸系统疾病与直径小于2.5微米的颗粒物（PM2.5）或细颗粒物之间的关联。然而，由于很少能获得来自环境监测器的每日细颗粒物数据，许多研究使用了基于当地机场观测到的能见度范围对PM2.5进行的估算。本文研究了基于能见度估算的PM2.5对位于洛杉矶大都市区的圣贝纳迪诺县和里弗赛德县1980年至1986年死亡率的影响。在控制协变量（包括季节、星期几、最高温度和露点）的同时，使用多元回归分析来分离估算的细颗粒物对死亡率的影响。结果取决于季节。在夏季季度，估算的细颗粒物与总死亡率（RR = 1.03，95% CI = 1.00 - 1.05，在平均PM2.5值为32.5微克/立方米时评估）和呼吸系统特异性死亡率之间存在小但具有统计学意义的关联。然而，就全年而言，估算的细颗粒物与死亡率无关（RR = 1.00；95% CI = 0.99 - 1.02）。使用估算的细颗粒物会给分析引入额外测量误差。在夏季季度，还检测到臭氧对死亡率的影响，但这种关联可能是由于与温度的混杂作用。敏感性分析表明，夏季季度发现的细颗粒物关联对于从能见度范围推导细颗粒物的替代估算、替代回归规范、函数形式和暴露平均时间而言是稳健的。这些发现与最近另一项关于洛杉矶县死亡率的研究一致，并补充了颗粒物与各种呼吸系统疾病结局之间关联的其他发现。
