There must be a highefficiencyairfilter provided at the air outlet point.
在空气出口点必须提供一台高效空气过滤器。
2
A great progress for highefficiencyairfilter media was obtained over the last years, and its' application became more extensive.
近年来，高效空气过滤材料取得了很大进展，应用也日益广泛。
3
On most commercial planes, at least half of the air comes from outside the aircraft and passes through a high-efficiency particulate air, or HEPA, filter which removes contaminants