关于空气净化器的案例与吐槽

关于空气净化器的案例与吐槽

我不是大气方向的,真的不是,这得先说明白了。

关于空气净化器,我持有的观点是这货对降低室内颗粒物浓度有帮助,但是否对健康有帮助不清楚,这个观点来自于之前看过的一个研究空气净化器及家庭辅导与室内儿童哮喘及二手烟暴露的案例。free的。

A Randomized Trial of Air Cleaners and a Health Coach to Improve Indoor Air Quality for Inner-City Children With Asthma and Secondhand Smoke Exposure

简单说下,研究人员将有哮喘病史与家庭吸烟人员的儿童分了三组,一组给空气净化器,一组给空气净化器,另外派了专业人士辅导,另一组是对照,但出于伦理需求,实验结束后给了空气净化器。之后测定了实验期间室内的PM2,尼古丁及尿可铁宁的浓度。结果发现,相比对照组,PM2.5及PM2.5-10浓度明显下降,但尼古丁与尿可铁宁浓度没啥变化。同时家庭辅导没啥用,无症状现象空气净化组较对照显著提高。所以研究人员就说了,空气净化器可能降低室内颗粒物浓度并提高儿童哮喘无症状天数,但对二手烟暴露没啥用。

看到这里你会奇怪为什么不能建立空气净化器与健康的关系,原因很简单,证据不足以得到这个广泛性的结论。健康与污染物的关系可以是因果的,空气净化器与污染物浓度的关系可以是因果的,但是研究只能控制其中一种或几种,并不能穷举所有污染物,况且颗粒物又是很笼统的污染混合物,所以这篇研究只是从一个角度去说在实验条件下的结论。你会在环境与健康领域的期刊上频频看到各种定语,例如这篇中的哮喘,儿童,室内等等,也许你会说就不能给个准信吗?不能,因为你要把所有能想到的条件都做随机化处理后,还要保证统计功效的话,这种级别样本数的实验谁也做不起,甚至样本你都收集不到。所以学术圈的人就会去做meta-analysis,把大家的研究总结下得到些普适但有点像是但不是废话的结论,这些结论会通过各种途径为政府决策服务,这其中就包括大家调侃最多的砖家意见。

扯这么多废话就是想说,我理解很多人喜欢要结论不看讨论的急切心情,但你要不了解些真实研究过程就总会觉得研究无用,结论废话,但不同于多数的废话,科研人员的废话也会有数据与统计的支持而不是想象。别着急下结论,被大数据洗脑的人总觉得得数据者得天下,实际上不论数据量大小,只要你想下结论都得是慎之又慎,不然可以看看当年神话般的google流感预测是怎么一步步被请下经典案例神台的。

好了, 最终还是给出一份大概可以回答空气净化器问题的综述链接

Can commonly-used fan-driven air cleaning technologies improve indoor air quality? A literature review

当然,我知道你不会点开链接,点开了也会说没权限看全文,其实看摘要就够了,当然也许你看多了会领悟到他们是在说一种太极拳式的废话,但对于想快速知道答案的需求还是多少有点帮助。下面是结论部分,解读时你要清醒的意识到,这是在说空气质量而不是健康,没人愿意捅马蜂窝,剩下的请自行脑补。

The conclusions are that:

(1) None of the reviewed technologies was able to effectively remove all indoor pollutants and many were found to generate undesirable by-products during operation.

(2) Particle filtration and sorption of gaseous pollutants were among the most effective air cleaning technologies, but there is insufficient information regarding long-term performance and proper maintenance.

(3) The existing data make it difficult to extract information such as Clean Air Delivery Rate (CADR), which represents a common benchmark for comparing the performance of different air cleaning technologies.

(4) To compare and select suitable indoor air cleaning devices, a labeling system accounting for characteristics such as CADR, energy consumption, volume, harmful by-products, and life span is necessary. For that purpose, a standard test room and condition should be built and studied.

(5) Although there is evidence that some air cleaning technologies improve indoor air quality, further research is needed before any of them can be confidently recommended for use in indoor environments.

题图出自 wiki commons

File:Trion Air Boss T1001 electrostatic air filter.png

编辑于 2014-10-15

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