Cost of air pollution

Death in the Air Infographic by World Bank

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The World Bank released a new report titled “The Cost of Air Pollution: strengthening the economic case for action” and in it they detail how air pollution is now the 4th leading risk factor for deaths worldwide. That’s worse than the deaths attributed to alcohol and drug use, HIV/AIDS, and even malaria. Besides the other reasons for reducing air pollution (climate change, our health, etc.) the economic one is probably the one that will communicate the strongest to everyone as air pollution costs the global economy in terms of foregone labor income to the tune of $225 Billion each year globally.

Click here for full report.

Click here to view the infographic in higher resolution.

Air pollution has emerged as the fourth-leading risk factor for deaths worldwide. While pollution-related deaths mainly strike young children and the elderly, these deaths also result in lost labor income for working-age men and women. The loss of life is tragic. The cost to the economy is substantial. The infographic below is mainly based on findings from The Cost of Air Pollution: Strengthening the economic case for action, a joint study of the World Bank and the Institute for Health Metrics and Evaluation (IHME).
Air pollution has emerged as the fourth-leading risk factor for deaths worldwide. While pollution-related deaths mainly strike young children and the elderly, these deaths also result in lost labor income for working-age men and women. The loss of life is tragic. The cost to the economy is substantial. The infographic below is mainly based on findings from The Cost of Air Pollution: Strengthening the economic case for action, a joint study of the World Bank and the Institute for Health Metrics and Evaluation (IHME).
Flickr Photo

Is Summer Air Better than Winter Air?

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Summer is here, bringing with it clearer skies and certainly cleaner air. Right?

Summer always seems to drive out the dense clouds of pollution that suffocate many Indian cities. However, while summer air is in fact cleaner than air during other seasons, it’s still far from safe according to the standards set by the World Health Organization (WHO).

During the winter, cold air traps pollutants close to the ground, a process called an “inversion.” Summer heat prevents this inversion, which does improve the air quality. However, average air conditions in India are still clearly not ideal.

Here’s a map of today’s pollution levels across India:

 

pollution levels
Source: https://aqicn.org/map/india/

 

On a day like today, when the AQI in Chennai, Hyderabad, Kolkata, Mumbai and New Delhi is in the ‘unhealthy’ or ‘very unhealthy’ range, we often wonder at Smart Air if the pollution in summer really is any better than the winter.

We got to the bottom of it by analyzing the US Embassy’s data in New Delhi and US consulates’ data in Mumbai, Chennai, Hyderabad, and Kolkata. So is summer air really better than winter air? We took the data from the past two years (June 2014 to June 2016) and broke it down into four seasons: winter (December to February), summer (March to June), monsoon (July to September), and post-monsoon (October to November). Next, we calculated the average particulate pollution (PM2.5) levels for each season.

Across the five cities we looked at, PM 2.5 levels were 26% better in the summer—118 micrograms in the winter compared to 49 micrograms in the summer. That means summer air is better.

Let’s take a look at the difference in PM2.5 between the five cities during different seasons:

 

 

US Embassy Air Quality Data
U.S. Department of State Data, June 2014 – June 2016. Air quality data may not be validated or verified

 

But how good is “better?” Here in India, “better” is nowhere near “safe.” Over the course of the two years we analyzed, average annual pollution levels in all five cities never fell below even the WHO’s more lenient (24-hour) exposure limit (25 micrograms per cubic meter). In fact, the average pollution levels across all the cities we tested was about 500% the WHO annual limit (10 micrograms) and 200% of the more lenient 24-hour limit (25)!

 

The lowest summer pollution level we found was Chennai (31 micrograms). But even that lowest summer level still surpassed the WHO limits.

Below are the 2-year graphs for each city. You can see that each city has two distinct swells in PM2.5 levels during the winter, each followed by 2 clear dips during the summer. Interestingly enough, comparing the summer and winter levels of each city from 2014-2015 to 2015-2016 shows some cities’ PM2.5 levels improving, while others’ increase between years. Most notably, Chennai’s winter pollution levels dropped significantly between years as did Hyderabad’s, while New Delhi and Kolkata experienced clear increases. However, we’re not sure whether or not this improvement and worsening of PM2.5 levels can be attributed to cities’ environmental efforts (or lack thereof).

The conclusion? The evidence is quite clear: summer air is in fact better than winter air. However, despite all the blue skies and warm days we’ve been having lately, there’s still a need to protect yourself inside and outside the house. Don’t mistake “better” for “safe.” Neither summer nor winter air meets WHO health standards and summer air is still of significant concern to public health.

 

Chennai US Department of State
U.S. State Department Data – June 2014 to June 2016. Data may not be fully verified or validated.

 

US Embassy Air Quality
U.S. State Department Data – June 2014 to June 2016. Data may not be fully verified or validated.

 

US Embassy Air Quality Data
U.S. State Department Data – June 2014 to June 2016. Data may not be fully verified or validated.

 

US Embassy Air Quality Data
U.S. State Department Data – June 2014 to June 2016. Data may not be fully verified or validated.

 

US Embassy Air quality data
U.S. State Department Data – June 2014 to June 2016. Data may not be fully verified or validated.

 

图片 1

空气污染口罩真的管用吗?

当全国各地的中国人(以及一大批住在中国的外国人)早晨醒来时都不得不面对严重的空气污染时,现实迫使十几亿中国人民需要在一个原本复杂的科学问题上成为专家——口罩真的管用吗?

从那时开始到现在,我已经给中国各地数以百计的人做过演讲,来分享如何保护自己免受空气污染侵害的知识。在这些演讲中,我听到了一些来自聪明又富有怀疑精神的人们的质疑。在这里我想回答这些疑问,因为很幸运地,聪明又富有怀疑精神的科学家们(再加一个献身科学的书呆子——我自己)已经用实实在在的实验和数据回答了这些质疑。

  1. “口罩不能过滤掉非常微小的颗粒”

怀疑派说:

最危险的颗粒是那些最小的颗粒。但是口罩这么薄,怎么可能捕捉到最小的颗粒?

科学测试:

爱丁堡大学的研究人员测试了不同种类的常用口罩。他们通过使用柴油发电机(模仿汽车排气装置)向不同口罩排放废气,然后用一个粒子计数器测出有多少颗粒穿透了口罩。下面是我画的实验示意图:

图片 1

一个重要的细节:他们使用的粒子计数器能够测量到小至0.007微米的颗粒。我们这里讨论的可是真正的微小颗粒!

首先他们用一个简单的棉质手帕做了测试。有时我在中国看到骑自行车的人会戴着这种手帕。

2

结果不是很好,过滤了28%的颗粒。

下一个测试的是便宜的医用口罩。

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效果不错!这个结果会让人感到意外(在密封性测试中它的表现会差大概20%,参考下面文章,但是已经比大部分人们直觉认为的结果好得多)。

然后他们又测试了一些自行车用口罩:

4

大部分能够达到80%。

接下来测试了一些便宜的3M口罩:

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这些口罩的都过滤了95%以上的颗粒。非常棒!

结论:即使是非常微小的颗粒,口罩也能过滤掉。

2.  “好吧,就算口罩能够过滤小颗粒,但是当你戴着口罩时,空气就从口罩的边缘漏进去了。”

怀疑派说:

理论上口罩是管用的,但是这些测试不是在真人脸上做的。当你真的戴着口罩时,它不能很好地贴合脸部,所以它们还是没用。

科学测试:

这个问题更难回答,因为你必须在实际戴着口罩的时候测试口罩效果。为了做到这一点,你需要一个非常昂贵的密封性测试仪器。幸运的是,在我好几周不断的请求下,3M公司终于同意我用他们在北京的实验室。

11

蓝色管子采集口罩外的空气,白色管子从口罩内采集空气(密封测试细节) 。

生活在北京的Richard Saint Cyr医生也做了口罩密封测试。所以我把我的数据跟他的数据做了个整合。这是不同口罩在我们脸上的效果:

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口罩对大多数人效果也这么高吗?

明确一点很重要:在我脸上做的测试不一定适用于其他人。但是,也有更广泛的实验数据。香港的研究者测试了22位中国人,结果发现3M口罩在他们脸上平均效果达到了99.5%。这个结果相当于Saint Cyr医生和我的测试结果中的最好成绩了。所以有实验数据说明在中国人的脸上,口罩也可以达到很高的密封性。

 

好口罩是贵的口罩吗?

下面的图是口罩测试结果和价格对比。

13

好在有效的口罩并不需要花费昂贵的价钱。而且为了呼吸到洁净的空气,我们不需要买个市面上最贵的口罩。

 

注意:关于气体污染

口罩的测试结果很好,但是也要注意:这些测试都是关于颗粒污染的。大部分市面上销售的口罩都不是用来过滤二氧化氮(NO2)或者臭氧(O3)的。所以口罩不是我们100%的保护伞。

 

    3.  有实验证明戴口罩有利于健康吗?

这可能是最难回答的一个问题了。然而,还是可以参考两个可靠的研究。研究人员在北京随机分配一组人戴着或者不戴口罩在北京走路,然后测量他们的心率和血压(12)。

Mask Study Blood Pressure CN

戴着口罩的时候,参加者血压更低而且心率更有规律。

15

结论:口罩可以过滤十分微小的颗粒,当你戴着口罩时也是这样。而且有专业研究结果表明戴着口罩有利于健康。这些应该足够让怀疑派们信服啦!

1

Do ionizers actually clean air?

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The other day, someone on Quora asked whether ionizer fans actually purify the air. This is an important question because ionizer purifiers are all over the place. For example, I was at a friend’s apartment in the US, and I saw his tower fan had an ionizer button on it:

image

It’s also important because several friends in China have sent me links to products like this:

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Amazing! A “miraculous purifier” that removes PM 2.5 and formaldehyde in just 30 seconds. And all that for far cheaper than regular purifiers and even cheaper than building your own purifier.

If this is true, my life in Beijing is now so much easier. But is it true?

So how do ionizers work? 

Here’s my bedroom, with an ionizer and bad particles in the air:

image

That ionizer shoots out negative ions:

image

Those ions cause the particles to stick to surfaces, like my bed, the wall, and the floor:

image

That’s the principle behind ion generators. It’s hard to see it happening with these tiny particles, but you’ve seen it on a visible scale if you’ve seen someone rub a balloon on their hair and then stick it to a wall.

image

But wait #1

A summary of scientific tests of air purifiers found that most ionizers have no noticeable effect on particulate levels (p. 8). Their conclusion is that most ionizers are too weak to have an effect. Studies do show an effect if they use very strong ionizers–much stronger than most ionizers on the market (p. 19).

But wait #2

OK, so regular ionizers don’t work, but we can use a big one! The problem is, when you put that many ions into the air, it produces ozone. Ozone is harmful, so that’s not good!

But wait #3

Even if we use a really strong ionizer and even if we can accept the ozone, you might have noticed that the ionizer didn’t actually filter out the particles. It just made them stick to my bed, wall, and floor.

First, that’s gross. Since the particles floating around here in Beijing include things like arsenic cadmium, and lead, I’d rather not have them stick to my pillow.

Second, they’re still a danger. The particles are just sticking to my bed. So let’s say Thomas comes home:

image

When I sit down on my bed, I’ll dislodge those particles, and they’ll float back into the air. Here’s my super scientific rendering of that process:

image

Those problems are what led Consumer Reports to publish tests and warn people not to buy the Sharper Image Ionic Breeze. Sharper Image sued Consumer Reports; Consumer Reports won.

So when people send me links asking about these “miraculous” purifiers, I tell them to steer clear.

Careful not to overgeneralize

But let’s not draw too broad of a conclusion here. This doesn’t mean ALL air purifiers are junk. Instead, I use HEPA filters. HEPAs actually capture particles, and they are backed by empirical tests (1, 2, 3, 4, 5, 6). Here’s a little test I did with HEPA filters in Beijing:

 

heart

Air pollution can break your heart

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For years, air pollution has been linked to heart disease but scientists haven’t been able to understand how, exactly, it breaks your heart. Last week, researchers in the U.S. released results from a long-term study that shed light; they found that air pollution thickens blood and hardens arteries, accelerating atherosclerosis — a disease in which plaque (calcium, fat, cholesterol and other substances) builds up in arteries, preventing oxygen-rich blood from reaching organs or body parts. This leads to the development of other diseases based on which arteries and body parts are affected, including heart attacks, stroke, or even death.

The study tracked 6795 participants in 6 U.S. cities between the ages of 45-84, all without a previous history of cardiovascular disease. Participants ranged from four ethnicities and came from a variety of socioeconomic backgrounds. Researchers then scanned participants’ arteries over a course of 10 years.  At the same time, they measured concentrations of PM2.5 and traffic-related gases called nitrogen oxides (NOx) outside participants’ homes, while creating estimates for the concentrations of pollution participants inhaled during time spent indoors.

The study found that PM2.5 and NOx were strongly associated with the build up coronary artery calcium, which accelerates atherosclerosis. Joel Kaufman, the lead author and a professor at the University of Washington, explained to ThinkProgress that air pollution may trigger cell inflammation, affecting white blood cells that protect the body against infectious diseases. As white blood cells accumulate, they build up plaque, causing atherosclerosis. This mechanism may explain why air pollution has also been linked to cardiovascular problems and mortality.

In the study, participants’ pollutant concentrations between the years 2000 and 2010 ranged from 9·2 to 22·6 μg/m³ for PM2.5 and 7·2 to 139·2 parts per billion (ppb) for NOx. For every 5 μg/m³ increase in PM2·5 and for every 40 ppb increase in NOx, coronary calcium deposits progressed by about 20%.

Though the results of the study are sobering, it’s important to note that the study was done in the U.S. under air pollution levels that fall well below the World Health Organization’s recommended PM2.5 exposure of 25 μg/m³.

Comparatively, North Indian cities tend to have significantly higher annual average PM2.5 levels, with Gwalior at 176, Patna at 149, and Delhi at 122. Further research needs to be conducted to understand how such high levels impact the severity of plaque build up and heart disease. However, a comprehensive Global Burden of Diseases, Injuries, and Risk Factors Study calculated that about 5.5 million people prematurely died in 2013 because of indoor and outdoor air pollution.

 

cost-effective

能不能降低安全空气的价格而不牺牲效果?

我开始做DIY空气净化器之后,很快就有人冒出来模仿我的DIY。我不介意,因为我把制作说明发布到网上,所以谁都可以做,并不是一定要用我的。不过,我看到两家价格比我便宜,还说我太贵了!

作为一个书呆子,我第一反应是要研究。所以我订了他们的货,发现他们用的风扇更小,而用的HEPA捕捉颗粒效果特别低。HEPA一般能捕捉99%的0.3微米及以上的颗粒;我发现这个更便宜的HEPA捕捉了85.8%(测试)。

有没有办法让HEPA再便宜?

不过,如果能有同样效果但更便宜的HEPA就更好了。所以我开始测试宽度稍微小一点的HEPA。为什么呢?因为HEPA能便宜6%,但是宽度还足够盖上风扇的出风口。

测试

作为一个书呆子,我还是想先去测试,以确认效果没有降低。所以我用DIY 1.0 + 29mm HEPA做了10次过夜房间测试,然后跟我之前发布30mm HEPA的测试比较了

测试是在北京的15㎡卧室里做的。空气测试仪是一台Dylos DC1700,能测到0.5微米颗粒(手提空气测试仪跟大使馆官方测试仪相比,准不准?)。

e

为了算效果,我算了起床之前最后4个小时的颗粒污染浓度,然后跟没开净化器的时候比较。同时我记录了外面的PM 2.5数据。以下是其中一天测试:

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结果

10次测试,DIY 1.0 + 29mm HEPA平均减少了86%的0.5微米颗粒和91%的2.5微米颗粒。

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这个测试结果是说明29mm的HEPA效果跟30mm HEPA没有区别。所以我把HEPA的价格降低6%,从80元到75元。书呆子这回高兴了!

HEPA价格对比

从性价比看,淘宝上Blue Air HEPA要359元,IQ Air要2,150元(还有长期使用成本对比)。

r

书呆子注释:实验重做

做实验的时候,科学家注重replication(重做)。如果一个现象是真的,应该能在不同的实验当中重做而得到类似的结果。虽然做这次测试的时候,重做不是主要的目标,这系列的测试是我测试DIY 1.0的第三个系列的测试 (包括早期测试200天长期寿命测试)。再加上美国医生Dr. Saint Cyr的测试,被重做的次数已经足够。

公开数据

跟之前一样,为了其他学霸同胞们,我发在下面布了原始数据和测试方法细节。

原始数据

1

2

3

4

 

户外PM 2.5的波动

我觉得这种几个小时的测试比常见的20分钟测试(比如CADR测试)更好,因为这是我们用空气净化器的更常见的方式。不过,八个小时测试的短处是,做测试的时候,外面的PM 2.5有可能会上升或者下降。如果外面PM 2.5下降,会夸大净化器的效果。如果外面PM 2.5上升,会低估净化器的效果。

如果算10次测试的平均值,这些波动应该会互相取消,但是还是值得分析数据,确定外面PM 2.5的波动没有影响结果。这10次测试当中,两天(9/25和11/10)的PM 2.5数据有比较大的波动。我去掉这两天的数据之后,平均消除的颗粒数据基本没变:84%的0.5微米颗粒和91%的2.5微米颗粒。

测试中户外PM 2.5

也值得看看测试的那10天,外面PM 2.5是不是跟北京平常PM 2.5水平一样。这10次测试的时候,外面PM 2.5平均值是116微克。这个比北京近5年的平均PM 2.5高差不多20微克(以我分析的美国大使馆PM 2.5数据为准)。所以这些测试能够代表北京常见的PM 2.5水平或者甚至更高的水平。

5

How visible is India’s air pollution?

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Much too visible, according to Astronaut Scott Kelly, who is finishing up his year onboard the International Space Station. On January 12th, Kelly posted the following picture, which shows northern Uttar Pradesh on the left, and the Himalayas and Nepal on the right.

http://twitter.com/StationCDRKelly/status/686824104096350208/photo/1

In December 2014, NASA released a similar picture highlighting the difference in pollution between India and Nepal.

The pictures get part of the story right. Pollution in North India may be much higher than pollution in northern Nepal. 13 of the 20 most polluted cities in the world are in India, with a large majority in northern India. Though northern Nepal may have better air quality due to the Himalayas, Nepal as a whole may not be significantly better.  Yale’s Environmental Performance Index, which compares air quality among 181 countries, ranked India at 178 and Nepal at 177 – both among the lowest in the world.

Nepal’s low rankings may stem from Kathmandu Valley, whose bowl-shaped topography traps warm, polluted air along with dust and smog. Though the government-installed air monitoring devices in Nepal have been out of order since 2007, a Yale graduate student, Anobha Gurung, conducted PM 2.5 tests in 2009. She found that in certain urban areas, traffic police were exposed to over 500 ug/m3 of PM 2.5 per hour – that’s over 200 times the World Health Organization’s recommended level of 25 ug/m3!

So overall, is Nepal’s air quality that much better than India as the pictures suggest?  Though northern Uttar Pradesh may be worse off than northern Nepal, it’s hard to say. The limited data of Kathmandu and northern Indian cities suggests people may be breathing similar levels of pollution, but we won’t really know until those air monitoring devices in Nepal start working again!

Exactly how much does Diwali harm Delhi’s air?

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News reports this year suggested that people are now more aware that fireworks increase air pollution in Delhi, and there were reports of reduced sales of fireworks. But with 22 million people, Diwali must go on. So that got me to thinking: just how bad does Diwali make our air?

To get to the bottom of it, I stationed our trusty Dylos DC1700 particle counter on my porch. I tracked (outdoor) air quality before, during, and after Diwali in Green Park, New Delhi. Here’s what I found:

Diwali Pollution Graph 2015

Nerd note: I converted the Dylos 0.5 and 2.5 micron counts to approximate PM 2.5 ug/m3, which then gives us an AQI.

The left axis is PM2.5 and the colors represent the range of the AQI in ug/m3. Also plotted on the graph are some averages to put things in perspective.

Delhi winter air averages 220 micrograms/m3, but during the peak Diwali fireworks on November 11, our numbers spiked to almost 700 micrograms/m3! That’s 28 times the WHO 24-hour limit of 25 ug/m3.

By comparison, Beijing’s air is often criticized, but Delhi peaked at about 7 times the Beijing average.

I always look forward to Diwali, but I’ll be packing a pollution mask!

2

蒙古有空气污染吗?

图片 1

据英国《卫报》, 乌兰巴托是世界大都市空气污染最严重第二。 2008-2011年,乌兰巴托PM 2.5平均值接近150微克;北京2014年平均PM 2.5是98微克;世界卫生组织24小时上限是25微克。

2

是快速发展的工业生产的原因吗?工业化的工厂只占蒙古经济极小的部分。满街都是汽车尾气?也不是。

3

实际上,乌兰巴托大部分的空气污染来源是冬天供暖烧煤。在冬天温度达到零下40度的地方确实需要供暖。

研究者发现那么严重的空气污染导致首都人口有10%的早逝。这意味着乌兰巴托急需清洁空气的好办法。

Smart Air将在乌兰巴托举办首场蒙古DIY空气净化器沙龙!欢迎蒙古首都朋友们在9月11-12日加入我们洁净空气活动。

欢迎加入我们DIY沙龙,了解如何用简单的DIY空气净化器减少家里的有害颗粒污染。Smart Air创始人Thomas Talhelm将解释非常贵的空气净化器的工作原理及如何利用同样的道理保护自己和保护自己的钱包。参加者在现场制作自己的DIY空气净化器带回家。

Video: Air pollution in Delhi is affecting school kids

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New study in India directly links air pollution to deteriorating health of school kids in Delhi. The Indian Express has put together a video to highlight the major findings of the study:

 

[youtube https://www.youtube.com/watch?v=RqpJSZH-834&w=560&h=315]