---
title: Billions of Particles, Countless Fibers, and Nine 9s
description: Entegris’ Rob Zeller walks us through the long history of gas filters and the adaptations of materials, technology, and people to find the purity needed in every aspect of our lives.
---

[Entegris Blog | Ensights](https://blog.entegris.com)

# [Billions of Particles, Countless Fibers, and Nine 9s](https://blog.entegris.com/billions-of-particles-countless-fibers-and-nine-9s)

 Written by [Entegris](https://blog.entegris.com/author/entegris) | Jan 23, 2023

Here’s a challenge, say the number 9 out loud, nine times.  
9, 9, 9, 9, 9, 9, 9, 9, 9.

|  |
| --- |
| *Figure 1: Filters have been used throughout history to prevent contaminants from reaching people and processes.* |

That’s easier to read than to say out loud. Nine “9s” represent 99.9999999% gas filter removal efficiency for protecting semiconductor chips during their manufacture. Historically, gas filters have taken on a variety of formats to manage the purity of gases, including the oxygen we breathe. Across their many uses, gas filter purity requirements and capabilities vary. In comparison, an N95 mask is 95% efficient, or 1.5 “9”s.

Why nine, “9s”, billions of minute particles, and countless fibers? The purity requirement of semiconductor gases is 99.9999999%. Entegris’ Rob Zeller walks us through the long history of gas filters and the adaptations of materials, technology, and people to find the purity needed in every aspect of our lives. Small particles and fibers are the foundations of choice for today’s most effective gas filtration solutions.

 

Learn more about controlling gas contamination [www.entegris.com/gas-filters](https://www.entegris.com/en/home/resources/industry-insights/gas-filtration-solutions.html)

 

[View full post](https://blog.entegris.com/billions-of-particles-countless-fibers-and-nine-9s)

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