The city's average concentration of PM2.5 was 28 micrograms per cubic meter during the period.

在此期间，北京PM2.5的平均浓度为每立方米28微克。

Phloem from the tree at the eruption site had 9.5 micrograms of the metal per kilogram.

位于喷发点的树上的韧皮部中每千克含有9.5毫克汞。

The concentrations of 70 micrograms per liter.

浓度为每升70微克。

Those cities both measured at over 92 micrograms.

这两个城市的PM2.5浓度都超过了92微克/立方米。

For comparison, the annual U.S. budget would be enough to create only a few micrograms of antimatter.

相比之下，美国每年的预算足以制造出几微克的反物质。

One microgram is the lethal dose for a human being.

只需百万分之一公克的钸，就足以致命。

The average concentration of PM2.5 hazardous particles was 30 micrograms per cubic meter, down 9.1 percent year-on-year.

细颗粒物（PM2.5）平均浓度为 30 微克/立方米，同比下降 9.1%。

The WHO recommends a reading of no more than five micrograms.

世界卫生组织建议读数不超过5微克。

The Chinese city of Hotan was second, with 94.3 micrograms.

中国和田市位居第二，PM2.5浓度为94.3微克/立方米。

Even a small amount (less than a microgram) is enough to kill a healthy adult.

仅仅很小的量（小于一微克）就足以杀死一个健康成年人。