In Krakow, 17.96 nanograms per cubic meter; in New York City, 2.26.
在克拉科夫,每平方米17.96纳克;在纽约,每平方米2.26纳克。
For nicotine, that level was a mere 1.8 nanograms per milliliter — too low to be picked up in tests.
对于尼古丁,仅仅是1.8毫微克每毫升,太低而不易提取。
Optimal levels range from 30 nanograms per milliliter to 40 nanograms per milliliter, the researchers said.
研究人员说,最佳水平范围是每毫升30到40纳克。
应用推荐