空气质量标准州与州不同。

Air quality standards vary from state to state.

youdao

这结果至少超过了美国国家空气质量标准的4倍。

That's at least four times greater than exposure standards set by U.

youdao

这结果至少超过了美国国家空气质量标准的4倍。

That's at least four times greater than exposure standards set by U.

youdao