Sep 082009
 

 

pollution2This is definitely one of the top 10 issues that expats discuss, even before they arrive here. Yes, the air quality is an issue, but it’s important to review the facts as well.

Blue Air Days

First, subjectively and objectively, the air is definitely better than it was compared to a year ago. We’ve had a lot of clear days this year! The government stats agree; “blue air days” with a PM10 rating in their safe range under 100 are the best in over 10 years. But let’s talk about how relevant that really is. First, the government uses a “blue air” pollution index using an air particulate size of 10 micrometers (PM10). That’s a tiny particle, but one issue is that this PM10 is not what most countries use as a proper indicator of air pollution, using a smaller size of 2.5 micrometers. Why? Because this size is more easily inhaled deeper into the lungs and therefore probably causes more damage, so is a more accurate barometer of health risks. Also, the government cutoff of PM10 under 150 (or API under 100) as a “blue sky day” still would count in most other countries as unhealthy. The WHO 2005 Guidelines have 20μg/m3 as the cutoff. There’s a general consensus that, while no number is a safe number, a PM10 over 20μg/m3 starts to have health effects. Therefore, saying you have a “blue sky day” with a PM10 level still in the 90’s would be falsely reassuring.

You’ve probably heard recently about the US Embassy’s air monitor, which is on top of their Chaoyang building and takes hourly PM2.5 readings which are put onto their Twitter page, and which is now accessible through the non-Twitter site iphone.bjair.info. This is a mildly sensitive issue as it often reports a higher number than the government’s PM10 readings. But, it is important to realize that you cannot compare them apples-to-apples, since the measuring sizes aren’t the same, and the government figures are an average of the multiple Beijing weather stations. Plus, the PM2.5 number is about equivalent to 50% of the PM10 number (i.e., a PM10 of 100 = a PM2.5 of 50). But for me personally, the Embassy numbers are relevant since I live and work in their neighborhood.

Click on image for larger picture
Click on image for larger picture

Can I Jog Outside Or Not?

OK, enough of the intro. In real life terms, there is definitely a risk from air pollution to your health. The underlying damage seems to be the tiny particles getting sucked deep into your lungs and initiating an inflammatory response — and long term exposure has a dose-response increase in chronic bronchitis, lung cancers, and atherosclerotic heart disease. It has been studied extensively, and I have links below to a couple of the best articles. In one recent New England Journal of Medicine study, every 10 microgram per cubic meter decrease in PM2.5 levels increased life expectancy by 0.6 years. Other studies have shown a similar effect; long term exposure to higher levels of particulates can reduce life expectancy by 0.6 to 1.3 years. (read the article and review, linked below).

What level is safe? Well, the WHO Air Quality Guidlines say the average PM10μg/m3 number should be under 20 μg/m3 to stop the increase in mortality. In 2005 (see the above table), Beijing’s average was over 100 μg/m3.

So, how does this affect your daily life? I think you should read these scholarly reviews yourselves, then occasionally monitor the published numbers and make your own conclusions and decisions, especially if you and your children plan to live here more than a few years. If you like to jog and bike, you should avoid all main and ring roads and avoid the worst days, but you certainly shouldn’t stop exercising outside, since the overall benefits far outweigh the risks.

I think one take-home concept is that air pollution is a pro-inflammatory disease, and that you should be extra aware of having an optimum anti-inflammatory lifestyle and diet. That includes the obvious things like not smoking, and exercising at least 150 minutes per week. Your diet should focus on fruits and vegetable, grains, beans, and good fats. But you could also consider supplements and herbals proven to be anti-inflammatory (usually meaning the same as “anti-oxidant”). That includes vitamin C but also omega 3 fatty acids found in some fish, as well as coenzyme Q10 and others. I personally have a daily regimen of 1 gram omega 3 supplement, as well as CoQ10, as well as a morning smoothie including spirulina.  I strongly recommend people think about these types of proactive health measures, not just for air pollution but for overall health.

pollutionWhat About Indoor Pollution? And Air Filters?

Yes, the levels inside your house can also be dangerously high. It’s not just the outdoor pollution; there are many indoor pollutants as well that can build up. That’s why it’s important to open your windows, usually in the mornings (not overnight! Particulate levels are worst overnight) to clean out your house air. This brings up another perennial expat topic; air purifiers. I personally think they are useful, and I have one in my bedroom going 24/7. But not every doctor is convinced that it makes a big long-term difference. You can start to read more information at the US EPA’s Indoor Air website. We’ll leave the fun topic of “which filter is best?” for a later post & discussion…

Resources: A must-read is a 2008 article in Urbane China magazine, written by United Family Hospital ER Dr. Chickering. It’s a PDF file; article called “Air Supply” starts on page 29. Print it and show it to family and friends! You can also check out my previous post on air pollution.

Scholarly Articles:

  21 Responses to “Air Pollution: How Bad Is It, Really?”

  1. good article, thanks.

  2. Hi, I liked this post. One quibble: you say "every 10 picometer decrease in PM2.5 levels increased life expectancy by 0.6 years." I think that this doesn't sound right. A picometer is a measure of size (length), not concentration. So instead of the word "picometer" I think you need some reference to concentration of PM2.5 particles. I haven't yet read the journal article so I'm not sure what they say.

    • Oops! You’re right. I’ve corrected it: it should say :every 10 microgram per cubic meter decrease in PM2.5…” In other words, if the PM2.5 goes from 50 to 40, you’ve just gained 0.61 years of your life — if you were exposed long term. That “long term” is a bit vague in the studies, most likely at least 5 years exposure. So it’s difficult to extrapolate how much damage you may get by living here on a 2 or 3 year contract.

      • That makes sense.
        So, Beijing PM2.5 I think averages somewhere around 120 micrograms per cubic meter. Large U.S. cities may be at about 20. (Someone else may have better numbers?) Taking the estimates from the research paper at face value, living long-term in Beijing vs living long-term in the U.S. means a six-year decrease in life expectancy.

        Btw. I'm looking forward to your post on air filters — I may soon be in the market myself!

  3. fantastic post. btw the AMFIC site seems to indicate the best time for exercise is actually noon … do you think that's the case? I'm a morning runner and I would have figured the mornings are best but apparently that's not true.
    http://www.amfic.eu/bulletin/index.php?region=bj&

    and presuming that I retain my habit of jogging in the morning, how much of a greater risk am i taking over running at noon?

    • Interesting, yesterday’s reading is lowest around noon. In my previous pollution post, it had been lowest around 7am. Maybe we do have to keep an eye on these graphs! I still think that mornings in general are best, and really more practical, since people usually work 9-5.

      I’m still not sure about wearing masks; there’s an interesting research article earlier 2009 that took Beijingers walking around first ring road with or without a mask (a 3M Dust Respirator 8812). They found a slight lowering of blood pressure; perhaps, long-term that could be beneficial. especially for persons with a history of really bad heart or lung disease. That 3M dust mask keeps out 96% of particles. I couldn’t find out if that mask is the same as 3M’s now-famous N95 mask everyone’s promoting for H1N1. By the way, this research paper also mentioned that a regular surgical mask keeps out 80% of dust; a cotton handkerchief only keeps out 72%…

  4. I just rediscovered a fantastic air pollution review, a March 2008 article in Urbane China magazine, written by United Family Hospital ER Dr. William Chickering. This is, by far, the most useful article I've seen on Beijing's pollution — and what you should do about it. It’s a PDF file you can download here: http://www.urbanechina.com/images/pdf/200803/Feat
    The article called “Air Supply” starts on page 29. I also linked it in my post above under "Resources". Print it and show it to family and friends!

  5. Air pollution can cause major short-term disease, as well. I was just reading about the great London Smog of 1952, which killed at least 4,000 persons just from a terrible 5-day smog period. The most vulnerable are always the youngest children and those with lung and heart diseases. People must remember a couple months ago, one day here when the air was like pea soup, and the smog haze was even indoors! Those scary days are getting more rare, thankfully. But if you're a smoker and also have high blood pressure, you need to take those worst days very seriously…

  6. A brand new study from well regarded journal Hypertension shows that high particulate levels in bad traffic can raise blood pressure and inflammation. This helps to confirm what we were discussing above. They were using a particulate level of 150 micrograms per cubic meter — a level which happens fairly often here. There's a news story of this in Time magazine at http://www.time.com/time/health/article/0,8599,19

  7. There's a new link above in the main article under "Resources", this time from the Wilson Institute's China Environment Series. This group has a series of outstanding papers, in PDF format.

  8. Great article. I didn't know about the Embassy's air monitor twitter feed.

  9. Interesting review from June 2009, an American-China research study on Olympic air shows it wasn't as clean as hoped. News review is here: http://www.usnews.com/articles/science/2009/06/21

    Some findings:

    "…Researchers found that particulate air pollution did drop by about one-third during the two-week Olympic period. But coarser particulate matter, PM 10, exceeded levels the WHO considers safe about 81 percent of the time, while the smaller particulate pollution PM 2.5, which can cause more serious health consequences, exceeded WHO guidelines 100 percent of the time.

    "It was a giant experiment and a noble effort. But in the end, the extra added measures didn't help reduce PM concentration as much as had been expected," said Staci Simonich, an associate professor of chemistry and toxicology at Oregon State University who worked on the study.

    There has been no evidence so far of any health problems linked to the short-term exposure of athletes or spectators during the Olympics, researchers noted.

    Further investigation suggested that weather conditions, such as rainfall and strong winds from the north and northwest, played a much larger factor in clearing the air than the pollution curbs.

    Meteorological conditions accounted for 40 percent of the variation in concentrations of coarser particulate matter, while pollution control measures accounted for only 16 percent, the study said…"

  10. Interesting review from June 2009, an American-China research study on Olympic air shows it wasn't as clean as hoped. News review is here: http://www.usnews.com/articles/science/2009/06/21

    Some findings:

    "…Researchers found that particulate air pollution did drop by about one-third during the two-week Olympic period. But coarser particulate matter, PM 10, exceeded levels the WHO considers safe about 81 percent of the time, while the smaller particulate pollution PM 2.5, which can cause more serious health consequences, exceeded WHO guidelines 100 percent of the time.

    "It was a giant experiment and a noble effort. But in the end, the extra added measures didn't help reduce PM concentration as much as had been expected," said Staci Simonich, an associate professor of chemistry and toxicology at Oregon State University who worked on the study.

    There has been no evidence so far of any health problems linked to the short-term exposure of athletes or spectators during the Olympics, researchers noted.

    Further investigation suggested that weather conditions, such as rainfall and strong winds from the north and northwest, played a much larger factor in clearing the air than the pollution curbs.

    Meteorological conditions accounted for 40 percent of the variation in concentrations of coarser particulate matter, while pollution control measures accounted for only 16 percent, the study said…"

  11. Thanks to Vance from the excellent environmental blog http://www.livefrombeijing.com for some corrections above. Check out his blog! It's a good resource.

  12. Thanks to Vance from the excellent environmental blog http://www.livefrombeijing.com for some corrections above. Check out his blog! It's a good resource.

  13. nowadays there is too much pollution in the air. most of the pollution from the air comes from fossil fuels. maybe someday we would use less and less of fossil fuesl in favor of clean and renewable energy sources.

  14. Air Pollution Threatens the Health of Children in China
    PEDIATRICS Vol. 122 No. 3 September 2008, pp. 620-628 (doi:10.1542/peds.2007-3143)

    http://pediatrics.aappublications.org/cgi/content

  15. It is really bad. We are advice to jog outside to breathe fresh air but now, I would prefer to buy tools/equipment so I can jog at home rather than getting all the dust and smell smoke from vehicles and cigarettes outside.

  16. How bad is the air? It’s very bad in many places. That’s why we decided to do what we can to help. We recently had air conditioning installers put in a more efficient and eco-friendly a/c.

  17. […] simplest way to monitor pollution is to follow the AQI, the Air Quality Index. There actually isn’t any level of air pollution considered perfectly safe; even an AQI of 20 can cause permanent damage with long term exposure. This is why the World Health […]

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