AIR QUALITY STANDARDS |
| Purafil’s environmental monitors use copper and silver sensors to measure air quality. The level of environmental corrosion is a primary indicator of how well controlled an environment may be. With more than 30 years of experience in providing clean air solutions, Purafil offers a comprehensive database of reactivity assessment results from museums, libraries, and archives worldwide. From these results, and taking into consideration currently recommended control levels, the following Air Quality Standards have been established. |
| Air Quality Standards for Preservation Environments | |||||
|---|---|---|---|---|---|
Copper Corrosion |
Silver Corrosion |
||||
Air Quality Classification |
Reactivity Rate (Angstroms / 30 days) |
Air Quality Classification |
Reactivity Rate (Angstroms / 30 days) |
||
C1 |
Extremely Pure |
< 90 |
S1 |
Extremely Pure |
< 40 |
C2 |
Pure |
< 150 |
S2 |
Pure |
< 100 |
C3 |
Clean |
< 250 |
S3 |
Clean |
< 200 |
C4 |
Slightly Contaminated |
< 350 |
S4 |
Slightly Contaminated |
< 300 |
C5 |
Polluted |
> 350 |
S5 |
Polluted |
> 300 |
| The purpose of the Air Quality Standards is to classify preservation environments according to the severity of copper and silver sensor corrosion. The standard identifies five Air Quality Classifications — extremely pure, pure, clean, slightly contaminated, and polluted — based on the rate of corrosion (measured in Angstroms) over a period of 30 days. Based on the above air quality standards, Purafil recommends the following levels of air quality for locations within the museum or archive: Class C1/S1: Archives, Metal Collections, Rare Books Class C2/S2: Museums, Museum Storage, Libraries Class C3/S3: Historic Houses Class C4/S4: Short Term Acceptable Class C5/S5: Not Acceptable |