Peracetic acid (PAA) is widely used in healthcare settings, including hospitals, for surface disinfection, equipment sterilization, and infection control. It is often applied in enclosed or semi-enclosed areas, where short-term airborne concentrations can develop during cleaning cycles or equipment use. Industrial hygienists are often asked to assess these short-term exposures close to the source. PAA presents a few practical challenges in air sampling. It is reactive, not very stable once collected, and commonly present alongside other oxidizers. In most commercial products, peracetic acid exists in equilibrium with hydrogen peroxide and acetic acid. Without proper control, hydrogen peroxide can interfere with analysis and affect the reliability of results.
Regulatory context
In Ontario, the Short-Term Exposure Limit (STEL) for peracetic acid is 0.4 ppm as inhalable vapour and mist (Ontario Regulation, 2017). This is a low limit, so sampling needs to be done over short durations with controlled flow rates and attention to potential interferences.
Analytical approach
LCS Laboratory Inc. analyzes peracetic acid using active air sampling with specialized sorbent tubes and a hydrogen peroxide removal pre-filter. This setup is selected to reduce interference from hydrogen peroxide and to improve confidence in the reported results when sampling mixed oxidizing environments.
Sampling parameters and applicability
Typical sampling conditions are:
• Flow rate: 1 L/min
• Sampling duration: 30 minutes
This method is intended for short-term exposure assessment, including STEL compliance, task-based monitoring, and evaluation of peak exposures during disinfection activities. It captures both vapour and mist fractions relevant to occupational limits.
Limitations and considerations
Because peracetic acid is reactive, sample handling and timing are important. Delays in shipment or improper storage can affect results. This method is not designed for long-term or full-shift sampling. Interpretation should consider the specific disinfectant used, application method, ventilation, and the presence of other oxidizing agents.
Typical applications in hospitals
This sampling approach is commonly used when:
• Assessing compliance with short-term exposure limits
• Evaluating staff exposure during cleaning or disinfection procedures
• Investigating irritation or odour complaints
• Documenting short-term exposure conditions for internal review or reporting
Working with LCS Laboratory
LCS Laboratory Inc. works with industrial hygienists and healthcare facilities to support peracetic acid air testing. The focus is on selecting an appropriate sampling approach and producing data that can be interpreted with confidence in a hospital environment. Peracetic acid sampling is sensitive to field conditions and method details. It is often helpful to review the sampling plan in advance. To discuss your project or schedule testing, please contact LCS Laboratory ©
