winter-is-coming

寒冬将至

又一次冬天,又一次PM 2.5来袭!面临北京冬天的PM 2.5,我开始想:冬天PM 2.5到底比夏天严重多少?

我分析了北京和上海美国大使馆近8年的PM 2.5数据,结果冬天平均PM 2.5比北京的夏天多30%。上海的冬天比夏天多60%。

冬天比夏天-北京 冬天比夏天-上海

这有多严重?世界卫生组织PM 2.5的24小时上限是25微克(年上线是10微克!)。那么北京夏天平均PM 2.5是上限的三倍多,在北京冬天是四倍多。

中国全国年图

你不在北京或者上海住吗?其他城市的空气也不安全!

寒冬将至,做好准备!

AQI levels across China

今天美国大使馆公布AQI是零!夏天的PM2.5一定低吗?

2016年9月9日-今天的中国空气污染地图。

来源://aqicn.org

美国大使馆正在显示PM2.5 的AQI是零!夏天真是这么好吗?其他地方呢?在下面了解更多。

几个月以前我们发布了北京夏天和冬天的空气污染水平变化报告。根据另外四个城市的美国大使馆数据,我们能够在更大范围内对中国主要城市夏天和冬天的污染变化情况有个了解。


美国大使馆推特账户

这次我们分析了上海、成都、广州和沈阳的大使馆数据。根据过去7年的数据,我们计算出了每个城市空气污染的月度和季度情况。

结果如何呢?通过对这四个城市的分析,我们证实了之前的关于夏天空气要比冬天更好的结论;四个城市的夏季PM 2.5数值平均要比冬季低29%。

 

 

可能的原因是,冬天的时候,通常情况下分散分布的空气污染物由于大气逆温现象,会在小范围内聚集。大气逆温现象是冷空气处于暖空气层下方,积聚在地球表面的一种大气现象。夏天的热量会阻碍大气逆温现象的出现。

在这四座城市里,夏天的PM2.5 水平只有冬天的71%。但这绝不是说夏天的PM2.5 水平就符合WHO(世界卫生组织)的标准。事实上,我们所分析的城市的夏天污染平均水平 (60微克/立方米)超出了WHO 24小时上限(10微克/立方米)的600%。

所有这些城市中,上海和广州的夏季污染水平最低(49微克/立方米,WHO上限的5倍)。夏季污染最严重的城市(除了北京)是成都。

 

 


空气污染水平月度情况:

 

根据美国大使馆的数据,我们也画出了所有城市空气污染水平的月度变化图,从这些图表可以很容易看出哪些城市污染水平最严重,以及在哪些月份比较严重。

 

以上图表明确显示了每个城市PM 2.5值的年度变化情况:污染水平在冬半年(十月—三月)上升,而在夏半年(四月—九月)有所下降。大多数城市7月和8月空气最好,虽然北京7月污染指数出现了一个令人费解的峰值——这很有可能是因为北京夏天较少出现可以吹走污染物的风。实际上,北京全年的空气污染变化是所有城市中最小的——污染数值持续保持在平均80微克/立方米的水平以上。

12月和1月在各个城市中都是污染最严重的月份,这很可能是因为冬季供暖会燃烧更多矿物燃料。

 

您可以在淘宝或者PayPal上找到我们200元和470元的空气净化器。也可以通过参加我们的沙龙活动,对我们的空气净化器和口罩测试有更多了解。

Air Quality Around the World

对不起,此内容只适用于美式英文。 For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language.

In the last couple of posts, we have mentioned that 13 of the world’s 20 most polluted cities are in India. The rest are in Pakistan, Qatar, Turkey, Iran, and Bangladesh. But the top 20 rankings made us wonder, how does India compare to the rest of the world? To find out, we selected a few cities from around the globe and mapped the World Health Organization’s 2014 air quality data. Due to variations in the frequency of data collection, WHO’s database contains data collected anywhere from 2010-2013, varying by city and country. The map below shows the outdoor air quality as measured by PM 2.5, or particulate matters that are two and a half microns or less in width. PM 2.5 are approximately 30 times smaller than human hair. Due to their size, they can lodge deeply into lungs and lead to health problems.

Air quality is drastically different across continents, but even cities with seemingly clean air see high-pollution days. Recently, the city of Stuttgart, Germany issued an air pollution warning and asked residents to leave cars at home in lieu of public transport to bring down pollution levels. Though Stuttgart averages healthy levels of air pollution on an annual basis, the city saw 64 days of pollution above EU’s recommended 40 µg/m³ for PM 10 in 2014. Stuttgart government issued the air pollution warning after pollution levels rose to 89 µg/m³ (PM 10) on January 19, 2016.

Similar to Stuttgart, other cities in Europe have taken measures to bring down air pollution. Even though these pollution levels are significantly better off than India’s, they are still above WHO and EU’s recommended levels. In 2014, Paris—like New Delhi—implemented an odd-even scheme to bring down pollution levels. Milan took more drastic measures in 2015 by banning all cars, motorcycles, and scooters between 10 am and 4 pm for a three-day period to bring down pollution levels. Contrastingly, London has introduced a congestion charge for those seeking to drive in the city during the day on weekdays. Beijing has also taken various measures, including putting limits on cars, factories, and construction sites on days with high levels of smog.

As Delhi government continues its debate on how to move forward with the odd-even policy, scholars from the Energy Policy Institute at the University of Chicago the Evidence for Policy Design group at Harvard University examined preliminary data to understand the pilot period’s impact. They found that the odd-even pilot reduced hourly particulate air pollution concentration by 10-13%, but doubted the scheme could work long-term. In Mexico City, a similar scheme led to worse pollution outcomes when households purchased second cars  or old, polluting cars to overcome the odd-even rule. The scholars called for a pilot on congestion charges akin to London’s to understand how this could lead to long-term reductions in air pollution.

As Delhi’s debates on how best to curb air pollution continue, however, many of the other cities that see dangerously high levels of pollution in India necessitate a louder public debate. Here is a chart showing the top 20 polluted cities around the world as compiled by the World Economic Forum. If you live in one of these cities, start the conversation!

 

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Filters and Fetuses

对不起,此内容只适用于美式英文。 For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language.

I don’t meant to be sensational, but I just got a picture from a friend of a friend who is pregnant and just started using the DIY filter three days ago. The filter is turning black already.

After all, scientific research suggests children are the most affected by air pollution. If the outrageous prices of filters are keeping pregnant women from cleaning their air, then the DIY filter has already started to change that.

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