FFU have primary and hepa two pole filter net.

ffu设有初、高效两极过滤网。

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

另一个原因是他乘坐的客机上设有高效微粒空气过滤器。

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

另一个原因是他乘坐的客机上设有高效微粒空气过滤器。

youdao