主题：雾霾到底有多毒 -- 向前向前

Now let’s consider air pollution. The most harmful pollution consists of small particulate matter, 2.5 microns in size or less, called PM2.5. These particles are small enough to work their way deep into the lungs and into the bloodstream, where they trigger heart attack, stroke, lung cancer and asthma. In the Berkeley Earth review of deaths in China we showed that 1.6 million people die every year from an average exposure of 52 μg/m3 of PM2.5. To kill 1.6 million people would require, assuming 1.37 x10-6 deaths per cigarette, 1.1 trillion cigarettes. Since the population of China is 1.35 billion, that comes to 864 cigarettes every year per person, or about 2.4 cigarettes per day.