In 1900, when the global human population was 1.5 billion, almost three million people – roughly one in 500 – died each year from air pollution, mostly from wretched indoor air. Today, the risk has receded to one death per 2,000 people.
1900年，全球人口只有15亿，而每年有近300万人——相当于500人中就有一人——死于空气污染，其中大部分是室内空气污染。如今，这一比例下降至2000人中才有一人死亡。尽管污染致死人数仍然比疟疾要高，但其致死率在下降而不是上升。