Cost of air pollution

Death in the Air Infographic by World Bank

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?

 

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.

 

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Do pollution masks work?

When a billion people in China (and quite a few expats) woke up to the severe air pollution in almost every city in China, it forced a billion people to become experts in a complicated scientific question. Do masks work?

Since then, I’ve given talks with hundreds of people all around China about how to protect themselves from air pollution. In those talks, I’ve heard doubts from smart, skeptical people. Here I’ll answer those doubts because, fortunately, smart, skeptical scientists (plus one dedicated nerd—yours truly) have empirically tested these questions.

Here are the two most frequent skepticisms I hear about masks.

  1. “There’s no way they capture the really small particles”

The skeptic case:

The most dangerous particles are the smallest particles, but masks are so thin. How could they possibly get the smallest particles?

The scientific test:

Researchers from the University of Edinburgh tested different common masks by running a diesel generator (to mimic car exhaust) and piping the exhaust through different masks. They used a particle counter to see how many particles made it through the mask. Here’s my super scientific rendering of the setup:

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One important detail: the particle counter they used measures down to .007 microns. We’re talking about truly tiny particles here!

First they tried a simple cotton handkerchief. Sometimes I see bikers in China wearing these.

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Not great, 28% of particles blocked.

Next they tried a cheap surgical mask.

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Surprisingly good! (Fit tests generally show lower results–see below–but still a lot higher than most people’s intuition.)

Next they tried several bike masks.

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Most were around 80%.

Then they tried several cheap 3M masks.

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They all scored over 95%. Pretty good!

Conclusion: masks capture even very small particles.

  1. “OK, they capture the small particles, but when you wear them, all the air just leaks in the side.”

The skeptic case:

Masks work in theory, but those tests aren’t on real faces! When you actually wear them, you can’t get a good enough fit, so they’re basically useless.

The scientific test:

This question is tougher to answer because you have to measure the mask while you’re actually wearing it. For that, you need a really expensive fit test machine. Fortunately, I begged and begged 3M until they let me use their lab in Beijing:

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The blue tube is sampling air outside the mask, while the white tube is sampling air from inside the mask (more details on the methods here).

Beijing-based Dr. Richard Saint Cyr also tested masks, so I’ll combine my data with his. Here’s how well the masks worked on our faces:

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How well do masks work for the broader population?

It’s important to make clear: fit test results on my face won’t always be the same for other people’s faces. However, there is evidence from a broader population that masks fit most people well. A scientific study of 3M masks on 22 Chinese people found a median fit score of 99.5%–essentially the same as the top results from Dr. Saint Cyr and me.

Best yet, effective masks don’t cost a lot of money. And you certainly don’t need to buy the most expensive masks on the market to breathe clean air.

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A note on gases: Note that these tests are about particulate pollution. Most commercially available masks don’t target gas pollutants like NO2 and O3, so it’s not 100% protection.

  1. Is there a documented health benefit of wearing a mask?

This is probably the hardest question to answer. However, there are two solid studies that have randomly assigned people in Beijing to wear masks or not and measured their heart rate and blood pressure (1,  2).

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While wearing masks, people had lower blood pressure and better-regulated heart rates.

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Conclusion: Masks capture even the smallest particles—even while you’re wearing them. And they have documented health benefits. That should be enough to satisfy even the skeptics!

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Do ionizers actually clean air?

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:

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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:

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That ionizer shoots out negative ions:

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

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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.

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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:

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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:

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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

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

Is it possible to lower the cost of clean air without sacrificing effectiveness?

A few months after I published my DIY tests, there were already Taobao stores up and running, selling DIYs even cheaper than my 200 RMB. I was intrigued. If we could really lower the cost of clean air, that’s a win!

But we have to be sure these cheaper machines are as effective. So I ordered the cheaper machines, tested them systematically, and found they performed much worse (2).

A New Way to Lower the Cost of Clean Air

But that doesn’t mean there aren’t ways to make HEPAs even more affordable. Recently I tested one way to do that: if we can shave 1 millimeter from the size of the HEPA, we can save 6% on the price. This new size still covers the fan opening, but does it still work as well?

Method

To test this question, my collaborator Anna ran 10 overnight room tests with the 29 mm in her Beijing apartment and compared it to my earlier tests of the 30 mm HEPA in the same 15m2 room.

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Like in my earlier tests, I calculated effectiveness as the percent reduction in particulate from the start of the test to the average of the last four hours. Here’s what one of those tests looks like with the reduction calculation laid out. The blue line is indoor 0.5 micron particles; the red line is outdoor PM 2.5

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Results

On average, the new 29mm HEPA reduced 0.5 micron particle levels in the room by 86% and 2.5 micron levels by 91%. These results were almost identical to my prior results with the 30mm HEPA.

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Conclusion

This new HEPA lets us lower the cost of clean air without sacrificing any effectiveness. Win! We just lowered the price of Smart Air HEPAs from 80 RMB to 75 RMB.

HEPA Cost Comparison

Next I took that price and compared it to the two biggest brands out there, Blue Air and IQ Air. (Also check out the long-run cost comparison .)

Nerd Note on Replication

As a side note, this test is now the third series of room tests I’ve published with the Original DIY (early tests; 200-day longevity test). Add that to Dr. Saint Cyr’s tests, and I’d say that’s a satisfying amount of reproducibility.

For fellow data nerds, I’m posting the original data and more details about the test below.

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Outdoor PM 2.5 Fluctuations

I like these long tests more than the common 20-minute tests (such as CADR tests) because this mimics how most people use purifiers. However, one drawback of these long tests is that outdoor PM 2.5 levels sometimes change over the course of 8 hours. If outdoor PM 2.5 drops, that can artificially inflate effectiveness. If outdoor PM 2.5 rises, that can artificially decrease effectiveness.

These changes should cancel out over 10 tests, but it’s worthwhile to re-run the analysis while excluding days with large outdoor changes. Among these 10 tests, two days (9/25 and 11/10) had large outdoor PM 2.5 changes. Without those two days, the averages were almost identical: 84% on 0.5 micron particles and 91% on 2.5 micron particles.

Average Outdoor PM 2.5 During Tests

It’s also worthwhile to check out bad outdoor PM 2.5 was during the tests to see if these days were representative of normal Beijing air. The average outdoor PM 2.5 was 116 micrograms. That’s about 20 micrograms higher than Beijing’s average PM 2.5 over the last five years (according to my analysis of the US Embassy’s PM 2.5 data). Thus, if anything, these tests are tougher than the Beijing average.

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How visible is India’s air pollution?

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?

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!

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Is Air Pollution a Problem in Mongolia?

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According to The Guardian, Ulaan Bator is the world’s second most polluted mega city. From 2008-2011, the average PM 2.5 level was nearly 150 micrograms. In 2014, Beijing averaged 98 micrograms; the WHO 24-hour limit is 25 micrograms.

 

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Is it a bustling manufacturing sector? Manufacturing is still a tiny percentage of the Mongolian economy. Cars filling the streets? Not that either.

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It turns out, most of Ulaan Baatar’s pollution is from people burning coal to keep warm. A little heat is necessary where winter temperatures dip to -40 C.

Yet all that air pollution causes 1 in every 10 deaths in the capital, according to an academic study. That makes clean air an urgent need in this city of 1.2 million people.

Smart Air will host its first-ever Mongolia workshops in Ulaan Baatar! Join us in the Mongolian capital September 11th and 12th.

Join us to learn how DIY purifiers can help remove dangerous particulate pollution from inside the home. Smart Air founder Thomas Talhelm will explain how even the priciest purifiers use a fan to push air through a HEPA filter. Workshop participants will make their own in just 10 minutes, and they’ll take it home to start breathing easier right away.