2013年5月18日星期六

Shanghai Air Pollution



Shanghai Air Pollution
PM10 and PM2.5

Whilst we might holistically judge daily air pollution by asking, "Can I see Alaska Pudong from my house?", a more scientific method measures the number of micrograms of PM10 and PM2.5 (particles measuring less than 10 micrometres and 2.5 micrometres respectively) per cubic metre.

These particles are caused by dust or emissions from vehicles, factories, construction sites and coal combustion. Fine particulates (PM2.5) can penetrate lungs and enter the bloodstream, making them the most detrimental to health. As you'd expect, chronic exposure leads to an increased risk of lots of nasty things, particularly heart disease and lung cancer.

Unfortunately, due to the government's convenient lack of data on PM2.5 levels (soon to be rectified), we're unable to analyze the findings in direct relation to Shanghai, but we can use it to draw comparable conclusions about our Shmoggy™ neighbor to the north, Beijing.

Before we look at the facts, it is important to note that the capital's PM10 levels are higher than Shanghai's, and it's PM2.5 levels are likely to be too. The reason is geographical: Shanghai is by the sea, which helps to rapidly clear the air, while Beijing lies in a valley surrounded by mountains.

So next time you fumble your way to the metro with less visibility in front of you than a Boeing in a bad storm, just remember that at least you aren't living in Beijing.

How does air pollution affect life expectancy?

Unfortunately, we can safely say that prolonged exposure to extreme air pollution leads to premature death - The World Health Organization estimated in 2007 that 656,000 Chinese die prematurely each year from ailments caused by indoor and outdoor air pollution - but exactly how much closer to the grave does it put us?

In 2009, one authoritative study found a decrease of 10 micrograms per cubic metre in a city's fine-particulate concentration was associated with an estimated increase in life expectancy of approximately 0.6 years.

Therefore, if we were able to remove all other factors, people living in Beijing would theoretically die five years younger than people living in America's most polluted city, Los Angeles.

The figure of course doesn't apply to officials who can't live without their own private Air Supply.

How does air pollution relate to lung disease and heart disease?

In contrast, Dr Richard Saint Cyr of My Health Beijing believes that the life expectancy figures may be misleading.

Instead, Dr Saint Cyr gauges the effects of air pollution by analyzing the percentage increases in the likelihood of developing diseases. In the case of Beijing, Dr Saint Cyr calculates that long-term living in the capital causes a 49% increase in lung cancer and 32% increase in heart disease deaths (when compared to perfectly clean air).

According to the World Health Organization's latest PM2.5 statistics, living in Beijing is thus significantly more lethal than other metropolises, including L.A. (12% and 19% respectively), London (11% and 19%), and Paris (17% and 21%).

To take a different (less scary) perspective, another study revealed that an individual spending 24 hours in Beijing will inhale 15% of a cigarette's worth of PM2.5. In other words, Beijing living is equivalent to smoking less than 1/6 of a cigarette each day.

Then again, it isn't much of a stretch to just go ahead and declare that the statistic is closer to at least 1/2 of a cigarette for the equivalent amount of PM2.5 people inhale in a day, since inhaling second-hand smoke is still prevalent in much of China.

And believe us, being next to spirals of cigarette smoke isn't nearly as sexy as Wong Kar-Wai and Mad Men make it seem.

In Shanghai, restaurant hygiene is denoted with a reassuring smiley faces. Could a similar system be used for air quality?
Is the air pollution actually getting better?

Beijing reported that 77.3% of days were 'blue sky days' over the past two years, which sounds lovely, but don't break out the picnic blankets just yet.

Applying EU standards to the same period shows that only 17.7% of those days would be considered 'medium' or 'low' pollution.

The government claims pollution levels have decreased, with the number of so-called 'blue sky days' increasing annually for 13 consecutive years being trotted out as evidence. However, research conducted over the past decade has shown PM2.5 levels increasing by 3-4% annually.

Added to this, Beijing lost its place in our environmental circle of trust when it shut down its two most polluted monitoring stations to raise its 'score' in 2006. In 2008 it even began monitoring from beyond the 6th ring road, 15-20km away from the city centre. Cheeky, Beijing, very cheeky.

Possibly more revealing than the shifty air quality statistics is the fact that Beijing's lung cancer rate has risen by 60% over the past decade, despite smoking rates remaining flat. "Increasing air pollution might be largely blamed for that," said Zhi Xiuyi, director of the Lung Cancer Treatment Center at Capital Medical University.

What's being done to decrease air pollution?

Thankfully, the government is now reportedly putting pressure on local authorities to tackle the problem.

In 2012, PM2.5 monitoring stations are to be introduced to 30 cities nationwide (including Shanghai), and last November the Ministry of Environmental Protection (MEP) announced that public opinion would soon be used to assess the performance of local governments on environmental protection.

If logo ideas are needed, we'd suggest going with something similar to the smiley face, unhappy face, disinterested face system used for hygiene levels in restaurants, except with normal face, surgical mask face, and Culturally Insensitive Olympian-style gas mask face instead.

So, in conclusion, this city may be gradually killing us all, but the health implications probably aren't as bad as the 'facts' you've previously heard. The random guy who told you that the pollution in Shanghai would give an adult elephant seven types of cancer in three hours (or something similar) didn't actually know what he was talking about.

没有评论:

发表评论

注意:只有此博客的成员才能发布评论。