Coal dust pollution in Beijing

It's no news that China's air pollution is bad. In fact if this NASA map of PM2.5 levels is anything to go by, Eastern China has it the worst in the entire world. But how come the air pollution in some Chinese cities is simply bad (like Guangzhou) while others are super bad (like Beijing?) And which provinces are actually doing anything about it?

Greenpeace recently took air quality statistics from China's Ministry of Environmental Protection and lined up 28 important cities located in the country's economic powerhouse regions to reveal what exactly is going on:

Beijing's air is really, really bad (duh), but so is Nanjing's and Hangzhou's

Beijing had the dubious honour of landing itself at the bottom of the 28 cities when it came to comparing PM10 levels. In 2010 the city exceeded World Health Organization standards for PM10 by a whopping 605%, hitting an average of 121 ug/m3 for PM10 (the WHO recommends a maximum of 20 ug/m3). Joining Beijing was Nanjing at number 27, and Hangzhou not far behind.

While Guangzhou and Shanghai both fared comparatively better, their PM10 levels were still around 3-4 times WHO standards. In fact, none of these 28 cities met WHO standards or grade-one national standards. And cause for concern, Shanghai saw a 25.3% increase in their PM10 levels for the first half of 2011 – one of highest of this group of cities.

Shanghai's air pollutant intensity 25x the national level

Ranking these cities by sulfur dioxide and nitrogen oxide emission intensity (that is, ton per km2) has seen Shanghai top other big polluters such as Beijing and Tianjin by a wide margin. The two pollutants can be pinned to two major sources: coal consumption and vehicles emission. In both, Shanghai beats all other Chinese cities with coal intensity at 9300 tons/km2 (compared to Beijing's 2600 tons/km2) and vehicle density at 4.66 million/km2 (compared to Beijing's 2.83 million/km2).

SO2 and NO emissions intensity

In short, Shanghai is burning though that coal and adding cars on the road like no other city in the country.

So how come Shanghai fairs better than many of its Chinese urban counterparts in terms of particle levels? PM10 is a measure of air pollutants after they've broken down into particles smaller than 10 micrometers, and when they get even smaller (e.g. PM2.5) become ever more dangerous as they're able to be absorbed deep in the lungs. And the disparity is thanks to a variety of geographical features (such as frequent rainfall, wind blowing out to sea) that means Shanghai can "flush out" its own pollutants quicker ... but leads to pesky things like acid rain and soil pollution.

Who's doing anything about it?

There are a number of things that need to happen if governments are serious about solving air pollution:

1. Make a plan that includes clear targets and clear timelines.
2. Place limits on total coal consumption.
3. Set targets to phase out heavy polluting vehicles and slow down vehicle use increase.
4. Disclose PM2.5 data.

Based on these four aspects, credit has to be given to Beijing and Shanghai who top the list in terms of action taken. Beijing gets top marks in all respects, with Shanghai dropping the ball in having not yet announced any kind of action plan, despite Chinese law stipulating that the governments of any city with substandard air quality must have a legally binding plan to meet this standard. The majority of the other cities also fail to deliver.

Also with 16-26% of inhalable particles contributed from sources outside of one's city it's important that the governments regionally co-ordinate plans, something only the cities of the Pearl River Delta has tried to do.

What can you do about it?

Keep an eye on air pollution levels. Publically released data is currently patchy, but we've gathered a list of air quality monitoring websites and apps for use.

Here's another good rule of thumb: when visibility is less than 5km you should think twice about being outside too long. Less than 3km and you should forget about going jogging and wear a mask outdoors. Less than 2km and you should really try to stay indoors and most DEFINITELY wear a mask when you head outside. But then again, blue skies don't always mean zero pollution.

There are three types of N95 masks that will help protect you from PM2.5. They're not that expensive (bought mine for less than 20RMB on Taobao) and can also be purchased in pharmacies. Wearing a mask will not only protect you, it will help send the message to other citizens that the air is dangerously polluted, and something does have to be done about it!

And to learn more, read the full report: Ranking Eastern Chinese cities by their "clean air" actions.