I consider if exposures are being controlled in line with the COSHH hierarchy of controls.

Where it is necessary to measure exposures to assess residual risks by inhalation, I use appropriate sampling techniques acceptable to the HSE.

I assess air sampling data against health-based exposure limits, in addition to Workplace Exposure Limits (WELs), where these values are significantly different.

When assessing if an exposure limit is complied with, I consider exposure data in accordance with BS EN 689:2018 “Workplace Exposure - Measurement of exposure by inhalation to chemical agents - Strategy of testing compliance with exposure limit values”. This is the methodology recommended by HSE in their re-issue of Guidance Note G409 in January 2022.