RIA Ultrasonic & Ozone Content Cleaning 3 — Questions and Answers
Question 1: What is the OSHA permissible exposure limit (PEL) for ozone as an 8-hour time-weighted average?
- 0.1 ppm (Correct answer)
- 1.0 ppm
- 5.0 ppm
- 10.0 ppm
Correct answer: 0.1 ppm
OSHA sets the PEL for ozone at 0.1 ppm (8-hr TWA) because even low concentrations can cause respiratory damage.
Question 2: At approximately what ozone concentration can most people first detect its characteristic odor?
- 0.001 ppm
- 0.01–0.05 ppm (Correct answer)
- 1.0 ppm
- 5.0 ppm
Correct answer: 0.01–0.05 ppm
Most people detect ozone's sharp, electrical smell at 0.01–0.05 ppm, which is at or below the OSHA PEL.
Question 3: How does ozone chemically eliminate malodors in restoration applications?
- It masks odors with a more intense scent
- It absorbs odor molecules into activated carbon particles
- It oxidizes odor-causing compounds, breaking their chemical bonds (Correct answer)
- It lowers the moisture content that supports odor-producing bacteria
Correct answer: It oxidizes odor-causing compounds, breaking their chemical bonds
Ozone's extra oxygen atom oxidizes odor-causing molecules, breaking their bonds and converting them into odorless or less offensive byproducts.
Question 4: Which material is most resistant to ozone degradation and therefore safe for constructing ozone treatment chambers?
- Natural rubber
- Latex tubing
- Stainless steel (Correct answer)
- Standard neoprene seals
Correct answer: Stainless steel
Stainless steel resists ozone oxidation, making it the preferred material for ozone-contact vessels and chamber construction.
Question 5: What respiratory protection is required when working in an area where ozone exceeds safe concentration limits?
- N95 particulate respirator
- Standard surgical mask
- Supplied-air respirator or SCBA (Correct answer)
- Activated carbon cloth mask
Correct answer: Supplied-air respirator or SCBA
Ozone is a gas that passes through particulate filters, so only supplied-air respirators or SCBA provide adequate protection at elevated concentrations.
Question 6: What happens to ozone naturally in a sealed, treated space at typical room temperature over time?
- It concentrates further due to off-gassing from surfaces
- It polymerizes into stable, long-chain compounds
- It decomposes back into oxygen (O₂) (Correct answer)
- It combines with nitrogen to form persistent nitric acid vapor
Correct answer: It decomposes back into oxygen (O₂)
Ozone is thermodynamically unstable with a half-life of roughly 20–30 minutes at room temperature, reverting to O₂ without any intervention.
Question 7: Which scenario correctly describes an appropriate use of ozone in a residential content restoration project?
- Running the ozone generator continuously with residents present to shorten treatment time
- Treating a sealed, unoccupied room for several hours after source materials have been removed and surfaces cleaned (Correct answer)
- Applying ozone at low levels while pets remain in the adjacent room
- Using ozone as the first step before any surface cleaning has been performed
Correct answer: Treating a sealed, unoccupied room for several hours after source materials have been removed and surfaces cleaned
Ozone treatment is effective when applied to an unoccupied, sealed space after physical cleaning has removed bulk contamination, maximizing contact with residual odor sources.
RIA Ultrasonic & Ozone Content Cleaning 3
What is the OSHA permissible exposure limit (PEL) for ozone as an 8-hour time-weighted average?