The concentrations of 70 micrograms per liter.

浓度为每升70克。

The levels of gold and silver were very small, in the micrograms, or even nanograms, but when you add them up it's pretty substantial.

“虽然金银的数量，克甚至毫克，但是它们加起来后的数量相当可观。”

Using Anroop Nair's human equivalent dose conversion, we can estimate that a 70 kg human would need a dose of 0.0013 milligrams or 1.3 micrograms per kilogram of NDMA.

使用 Anroop Nair 的人体当量剂量换算，我们可以估计，一个七十公斤重的人需要摄入 0.0013 毫克或 1.3 克每公斤 NDMA 的剂量。

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。

In India, New Delhi's measurement of 92.7 micrograms made it the most-polluted capital city.

在印度，新德里的PM2.5浓度是92.7克/立方米，使其成为污染最严重的首都城市。

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克。

The city's average concentration of PM2.5 was 33 micrograms per cubic meter in 2021, the lowest level since record-keeping began in 2013, Yu Jianhua, deputy director of the Beijing municipal ecology and environment bureau, said at a press briefing.

北京市生态环境局副局长余建华在新闻发布会上表示，2021 年，北京市 PM2.5 的平均浓度为 33 克/立方米，是自 2013 年开始记录以来的最低水平。

Polonium is a highly toxic substance and just one microgram -- about the size of a speck of dust -- is enough to kill a person.

钋是一种剧毒物，一克，也就一点灰尘大小的钋便可致人死亡。

The average concentration of the pollutants in the city fell by 9.5 percent year on year to 38 micrograms per cubic meter, the lowest since 2013.

全市污染物平均浓度同比下降9.5%，降至每立方米38克，为2013年以来最低。

The World Health Organization (WHO) has said cities should have a maximum measurement of just 5 micrograms of PM2.5 per cubic meter.

世界卫生组织表示，城市PM2.5的最高测量值应控制在5克/立方米。

The average concentration of PM2.5 in Beijing is 33 micrograms per cubic meter in the first 11 months of this year.

今年前 11 个月，北京的 PM2.5 平均浓度为每立方米 33 克。

The E.P.A. has set the safety threshold for PM 2.5 at a yearly average of 12 micrograms per cubic meter.

环保署给pm2.5设置的浓度限值为年平均浓度12μg/m3。

World Health Organization (WHO) guidelines recommend concentrations stay below an average of 15 micrograms per cubic metre over 24 hours.

世界卫生组织（WHO）的指导方针建议在 24 小时内将浓度保持在平均每立方米 15 克以下。

If they tested your urine and you had a higher concentration than 12 micrograms per millilitre, you were out.

如果他们检测你的尿液浓度超过12μg/mL，你就出局了。

The city's average concentration of PM2.5 stood at 33 micrograms per cubic meter in the January to May period.

在 1 月至 5 月期间，北京的 PM2.5 平均浓度为每立方米 33 克。

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克的反物。

124 micrograms is all it takes to kill you, about the same weight as two human eyelashes.

124 克就可以致人死亡，也就相当于人类两根睫毛的重量。

This week, a high of more than 1,000 micrograms was recorded in one part of South Korea.

本周韩国的一个地区创下了超过1000克的记录。

That compared with a 3 percent increased risk for every 3 microgram increase in non-wildfire particles.

相比之下，以非野火烟雾释放方式，颗粒物每增加3克，被诊断患有痴呆症的风险就会增加3%。

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。