And one of the primary measurements for the Index is particulate matter 2.5.
该指数的主要测量指标之一是“颗粒物 2.5”。
科学快报-科学美国人Science Quickly, from SCIENTIFIC AMERICAN
The CDC has been one of the major sources of COVID case data, but it's now going to lean on COVID death rates, emergency room data and hospital admissions for its primary national surveillance measurements.