ORIGINAL ARTICLE

Ambient Particulate Air Pollution and Daily Mortality in 652 Cities

Cong Liu, Renjie Chen, Francesco Sera, et al

Abstract

BACKGROUND 背景

The systematic evaluation of the results of time-series studies of air pollution is challenged by differences in model specification and publication bias.

由于模型特征的差异以及发表偏倚，系统评估大气污染的时间序列研究受到挑战。

METHODS 方法学

We evaluated the associations of inhalable particulate matter (PM) with an aerodynamic diameter of 10 μm or less (PM₁₀) and fine PM with an aerodynamic diameter of 2.5 μm or less (PM_2.5) with daily all-cause, cardiovascular, and respiratory mortality across multiple countries or regions. Daily data on mortality and air pollution were collected from 652 cities in 24 countries or regions. We used overdispersed generalized additive models with random-effects meta-analysis to investigate the associations. Two-pollutant models were fitted to test the robustness of the associations. Concentration–response curves from each city were pooled to allow global estimates to be derived.

我们评估了多个国家和地区可吸入颗粒物PM₁₀ 和PM_2.5 与每日全因、心血管和呼吸系统死亡率的相关性。收集了24个国家或地区652个城市每日死亡率及大气污染的数据。我们采用随机效应meta分析的过分散广义加法模型。我们拟合2个污染物模型以验证相关关系的稳健性。我们综合各个城市的浓度效应曲线，以得到全球的结果。

RESULTS 结果

On average, an increase of 10 μg per cubic meter in the 2-day moving average of PM₁₀concentration, which represents the average over the current and previous day, was associated with increases of 0.44% (95% confidence interval [CI], 0.39 to 0.50) in daily all-cause mortality, 0.36% (95% CI, 0.30 to 0.43) in daily cardiovascular mortality, and 0.47% (95% CI, 0.35 to 0.58) in daily respiratory mortality. The corresponding increases in daily mortality for the same change in PM_2.5 concentration were 0.68% (95% CI, 0.59 to 0.77), 0.55% (95% CI, 0.45 to 0.66), and 0.74% (95% CI, 0.53 to 0.95). These associations remained significant after adjustment for gaseous pollutants. Associations were stronger in locations with lower annual mean PM concentrations and higher annual mean temperatures. The pooled concentration–response curves showed a consistent increase in daily mortality with increasing PM concentration, with steeper slopes at lower PM concentrations.

平均而言，PM₁₀水平的2天移动平均值（代表当日与前一日的平均水平）每增加10 μg/m3，伴随每日全因死亡率增加 0.44% (95% 可信区间 [CI], 0.39 to 0.50)，每日心血管死亡率增加 0.36% (95% CI, 0.30 to 0.43)，每日呼吸疾病死亡率增加 0.47% (95% CI, 0.35 to 0.58)。PM_2.5 浓度若有相同程度升高，上述死亡率分别增加 0.68% (95% CI, 0.59 to 0.77), 0.55% (95% CI, 0.45 to 0.66) 和 0.74% (95% CI, 0.53 to 0.95)。对气态污染物进行校正后，上述相关性仍然显著。在年均PM浓度较低以及年均气温较高的地区，相关性更为明显。综合的浓度反应曲线显示，随PM浓度增加，每日死亡率均呈增加趋势，PM浓度较低地区的斜率更大。

CONCLUSIONS 结论

Our data show independent associations between short-term exposure to PM₁₀ and PM_2.5 and daily all-cause, cardiovascular, and respiratory mortality in more than 600 cities across the globe. These data reinforce the evidence of a link between mortality and PM concentration established in regional and local studies. (Funded by the National Natural Science Foundation of China and others.)

我们的资料显示，在全球超过600个城市，PM₁₀ 和 PM_2.5 的短期暴露与每日全因、心血管原因及呼吸疾病原因导致的死亡之间存在独立的相关关系。这些资料强化了区域及局部研究中报告的死亡率与PM浓度的相关性。

评论[仅代表个人意见]

• 并非专业领域，所以可能想法很幼稚。
• 个人认为，这类研究最难之处在于想明白，今天的大气污染究竟影响多久之后的死亡？为什么？
• 另一个问题似乎也不那么容易想清楚，如果PM₁₀ 和 PM_2.5 仅升高1天或2天，是否真的显著影响死亡率？为什么？
• 同样一个数据，如果纳入分析的指标不是大气污染，而是生活方式（如肉类或水果摄入等），是否就会得到其他的结论？为什么？