Peracetic acid (PAA) is increasingly used in food processing, healthcare, water treatment, and pulp operations, often in enclosed or semi-enclosed spaces. Consultants are frequently asked to assess short-term exposures near process equipment, cleaning operations, or disinfection cycles. The challenge is that PAA is highly reactive, unstable in air samples, and easily confounded by other oxidizers—making poorly designed sampling results difficult to defend.
Peracetic acid coexists with hydrogen peroxide and acetic acid in most commercial formulations. Without proper sample conditioning, hydrogen peroxide can interfere with analysis, leading to biased or false positive 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 low limit requires short-duration, high-quality sampling with well-defined flow rates and interference control to support compliance decisions.
Our analytical approach
LCS Laboratory Inc. analyzes peracetic acid using active air sampling with specialized sorbent tubes equipped with a hydrogen peroxide removal pre-filter. This configuration is specifically selected to reduce analytical interference and improve result reliability when sampling mixed oxidizing environments.
Sampling parameters and method applicability
Recommended sampling conditions are:
•Flow rate: 1 L/min
•Sampling duration: 30 minutes
This approach is best suited for STEL evaluations, task-based assessments, and investigations of short-duration peak exposures. The method captures both vapour and mist fractions relevant to regulatory limits.
Method limitations and considerations
Due to the reactive nature of peracetic acid, sample handling, timing, and storage conditions are critical. This method is not intended for long-term integrated sampling. Results should be interpreted alongside process conditions, formulation details, and concurrent use of other oxidizing agents.
When this method is most useful
Peracetic acid monitoring using this approach is most appropriate when:
•Assessing compliance with provincial STEL requirements
•Evaluating worker exposure during cleaning or disinfection tasks
•Investigating complaints related to irritation or odour
•Establishing defensible short-term exposure data in high-use environments
Why work with LCS Laboratory
Peracetic acid air testing using this sampling configuration is offered exclusively by LCS Laboratory Inc. We work directly with industrial hygienists and EHS consultants to confirm method suitability, sampling strategy, and data interpretation before samples are collected. The focus is on producing results that can withstand technical and regulatory scrutiny.
Discuss sampling before you collect
Because peracetic acid sampling is sensitive to method selection and field conditions, early consultation is strongly recommended. To discuss sampling strategy, equipment selection, or method limitations, please contact LCS Laboratory ©
