比如，燃烧更清洁的燃料有助于减少室外空气污染。 据世界卫生组织的数据，目前室外空气污染每年导致约370万人过早死亡。
For example, burning cleaner fuels helps to reduce outdoor air pollution, which, according to the World Health Organization, currently causes about 3.7 million premature deaths a year.