Abstract

Background:

Exposure to fine particulate matter (${\mathrm{PM}}_{2.5}$) during wildfire seasons has been associated with adverse health outcomes. Previous studies have focused on daily exposure, but ${\mathrm{PM}}_{2.5}$ levels in smoke events can vary considerably within 1 d.

Objectives:

We aimed to assess the immediate and lagged relationship between sub-daily exposure to ${\mathrm{PM}}_{2.5}$ and acute health outcomes during wildfire seasons in British Columbia.

Methods:

We used a time-stratified case-crossover study design to evaluate the association between modeled hourly ${\mathrm{PM}}_{2.5}$ and ambulance dispatches during wildfire seasons from 2010 to 2015. Distributed lag nonlinear models were used to estimate the lag-specific and cumulative odds ratios (ORs) at lags from 1 to 48 h. We examined the relationship for all dispatches and dispatches related to respiratory, circulatory, and diabetic conditions, identified by codes for ambulance dispatch (AD), paramedic assessment (PA) or hospital diagnosis (HD).

Results:

Increased respiratory health outcomes were observed within 1 h of exposure to a ${10\text{-}\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$ increase in ${\mathrm{PM}}_{2.5}$. The 48-h cumulative OR [95% confidence interval (CI)] was 1.038 (1.009, 1.067) for the AD code Breathing Problems and 1.098 (1.013, 1.189) for PA code Asthma/COPD. The point estimates were elevated within 1 h for the PA code for Myocardial Infarction and HD codes for Ischemic Heart Disease, which had 24-h cumulative ORs of 1.104 (0.915, 1.331) and 1.069 (0.983, 1.162), respectively. The odds of Diabetic AD and PA codes increased over time to a cumulative 24-h OR of 1.075 (1.001, 1.153) and 1.104 (1.015, 1.202) respectively.

Conclusions:

We found increased ${\mathrm{PM}}_{2.5}$ during wildfire seasons was associated with some respiratory and cardiovascular outcomes within 1 h following exposure, and its association with diabetic outcomes increased over time. Cumulative effects were consistent with those reported elsewhere in the literature. These results warrant further investigation and may have implications for the appropriate time scale of public health actions. https://doi.org/10.1289/EHP5792

中文翻译：

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野火季节次日接触细颗粒物和救护车调度：加拿大不列颠哥伦比亚省的个案交叉研究。

摘要

背景：

暴露于细颗粒物（${\mathrm{下午}}_{2.5}$）在野火季节与不良健康后果有关。先前的研究集中在每日接触量上，但是${\mathrm{下午}}_{2.5}$ 烟雾事件中的水平在1 d内变化很大。

目标：

我们旨在评估次日暴露与 ${\mathrm{下午}}_{2.5}$ 和不列颠哥伦比亚省野火季节的急性健康后果。

方法：

我们使用了时间分层的案例交叉研究设计来评估每小时建模之间的关联 ${\mathrm{下午}}_{2.5}$和2010年至2015年野火季节的救护车调度。使用分布式滞后非线性模型来估计滞后1到48 h的滞后特定和累积优势比（OR）。我们检查了所有与呼吸，循环和糖尿病状况有关的派遣与派遣之间的关系，这些关系由救护车派遣（AD），医护人员评估（PA）或医院诊断（HD）的代码确定。

结果：

暴露于皮肤的1小时内观察到呼吸健康结果增加。 ${10\text{--}\mathrm{\mu }\mathrm{G}/\mathrm{米}}^3$ 增加 ${\mathrm{下午}}_{2.5}$。AD代码呼吸问题的48小时累积OR [95％置信区间（CI）]为1.038（1.009，1.067），PA代码哮喘/ COPD为1.098（1.013，1.189）。心肌梗塞的PA代码和缺血性心脏病的HD代码的点估计值在1小时内升高，它们的24小时累积OR分别为1.104（0.915，1.331）和1.069（0.983，1.162）。糖尿病AD和PA码的几率随时间增加，分别达到24小时累计1.075（1.001，1.153）和1.104（1.015，1.202）的OR。

结论：

我们发现增加 ${\mathrm{下午}}_{2.5}$暴露后1小时内，在野火季节期间，与某些呼吸和心血管结果相关，并且与糖尿病结果的相关性随时间增加。累积影响与文献中其他地方报道的一致。这些结果值得进一步调查，并可能对适当的公共卫生行动时间表产生影响。https://doi.org/10.1289/EHP5792