http://wiki.china.org.cn/index.php?action=history&feed=atom&title=PM2.5 2026-05-13T07:44:47Z Revision history for this page on the wiki MediaWiki 1.34.2 http://wiki.china.org.cn/index.php?title=PM2.5&diff=32072&oldid=prev 2015-03-11T04:33:09Z

<p></p> <p><b>New page</b></p><div>[[file:PM.JPEG|thumb|250px|Thick smog engulfs Beijing.]]<br /> '''Particulate matters''' or '''PM''' , is the term for particles found in the air, including dust, dirt, soot, smoke, and liquid droplets. '''PM2.5''' ('''细颗粒物''') particles are air pollutants with a diameter of 2.5 micrometers or less, small enough to invade even the smallest airways. <br /> <br /> Particles less than 10 micrometers in diameter (PM10) pose a health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter (PM2.5) are referred to as &quot;fine&quot; particles and are believed to pose the greatest health risks. Because of their small size (approximately 1/30th the average width of a human hair), fine particles can lodge deeply into the lungs.<br /> <br /> These particles generally come from activities that burn fossil fuels, such as traffic, smelting, and metal processing.<br /> <br /> [[category:air pollution]]<br /> [[category:meteorology]]</div>

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