另一个原因是他乘坐的客机上设有高效微粒空气过滤器。

Another reason is that the planes he flew in were equipped with HEPA filters.

youdao

另一个原因是他乘坐的客机上设有高效微粒空气过滤器。

Another reason is that the planes he flew in were equipped with HEPA filters.

youdao