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

在多数商用飞机上，至少有一半空气是来自于飞机外部，而且都经过了一种高效空气净化装置的过滤。

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Inside your home, use a high-efficiency particulate air (HEPA) purifier capable of removing PM2.5 particles, or install such a filter in your heating system.

在你的家里，使用能够去除PM 2.5颗粒的高效颗粒空气净化器，或在你的加热系统中安装这样一个过滤器。

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But studies have shown that high-efficiency particulate air (HEPA) filters on most jets today can capture 99.97% of bacterial and virus-carrying particles.

但研究表明，如今大部分飞机上的高效微粒空气过滤器能够滤掉99.97%的细菌和病毒微粒。

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The letters H-E-P-A represent the words High Efficiency Particulate Air.

VOA: special.2009.07.14

High Efficiency Particulate Air (HEPA) filters, which usually last a year.

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Look for the HEPA (high-efficiency particulate air) label.

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