Environmental and Occupational Hazards Control Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Barcelona, Spain.
Environ Int. 2020 Jan;134:105299. doi: 10.1016/j.envint.2019.105299. Epub 2019 Nov 18.
Increased atmospheric particulate matter (PM) concentrations are commonly observed during desert dust days in Iran, but there is still no evidence of their effects on human health. We aimed to evaluate the association between daily mortality and exposure to PM and PM during dust and non-dust days in Tehran and Ahvaz, two major Middle Eastern cities with different sources, intensity, and frequency of desert dust days.
We identified desert dust days based on exceeding a daily PM concentration threshold of 150 µg/m between 2014 and 2017, checking for low PM/PM ratio typical of dust days. We used a time-stratified case-crossover design to estimate the short-term effects of PM and PM concentrations on daily mortality during dust and non-dust days. Data was analyzed using conditional Poisson regression models.
Higher concentrations of PM and frequency of desert dust days were observed in Ahvaz rather than Tehran. In Ahvaz, the effect of PM at lag 0 was much higher during dust days, an increment of 10 μg/m was associated with 3.28% (95%CI = [2.42, 4.15]) increase of daily mortality, than non-dust days, 1.03% (95%CI = [-0.02, 2.08]), while in Tehran, was slightly higher during non-dust days, 0.72% (95%CI = [0.23, 1.23]), than in dust days, 0.49% (95%CI = [-0.22, 1.20]). No statistically significant associations were observed between PM and daily mortality in Ahvaz, while in Teheran the effect of PM increased significantly during non-dust days at lag 2, 1.89% (95%CI = [0.83, 1.2.95] and lag 3, 1.88% (95%CI = [0.83, 1.2.95]).
The study provides evidence that exposure to PM during Middle East dust days is an important risk factor to human health in arid regions and areas affected by desert dust events.
在伊朗，沙尘暴期间通常会观察到大气颗粒物（PM）浓度升高，但仍没有证据表明其对人类健康有影响。我们旨在评估德黑兰和阿瓦兹两个中东主要城市在沙尘和非沙尘日期间，每日死亡率与 PM 和 PM 暴露之间的关系，这两个城市的沙尘日来源、强度和频率不同。
我们根据 2014 年至 2017 年期间每日 PM 浓度超过 150μg/m 的标准确定了沙尘日，并检查了典型的沙尘日低 PM/PM 比值。我们使用时间分层病例交叉设计来估计沙尘日和非沙尘日期间 PM 和 PM 浓度对每日死亡率的短期影响。数据分析使用条件泊松回归模型进行。
阿瓦兹的 PM 和沙尘日频率均高于德黑兰。在阿瓦兹，沙尘日时 PM 浓度的滞后 0 效应要高得多，与非沙尘日相比，浓度增加 10μg/m 与每日死亡率增加 3.28%（95%CI=[2.42, 4.15]）相关，而非沙尘日，浓度增加 10μg/m 与每日死亡率增加 1.03%（95%CI=[-0.02, 2.08]）相关，而在德黑兰，非沙尘日时的效应略高，为 0.72%（95%CI=[0.23, 1.23]），而在沙尘日，为 0.49%（95%CI=[-0.22, 1.20]）。在阿瓦兹，PM 与每日死亡率之间没有观察到统计学上显著的关联，而在德黑兰，PM 的效应在非沙尘日时在滞后 2 和 3 时显著增加，分别为 1.89%（95%CI=[0.83, 1.2.95]和 1.88%（95%CI=[0.83, 1.2.95]）。
该研究提供了证据表明，在中东沙尘日期间暴露于 PM 是干旱地区和受沙漠尘暴事件影响地区人类健康的一个重要危险因素。
