Background
Acute Exposure Guideline Levels (AEGLs) were developed by the US Environmental Protection Agency to evaluate the potential health impacts of accidental chemical releases into the air. They define concentration thresholds for three effect levels:
- Level 1: Noticeable discomfort or irritation
- Level 2: Irreversible or long-lasting health effects
- Level 3: Life-threatening effects
Challenge
Alkali Consultants were commissioned to support planning permission for a new data centre in East London. The Environment Agency (EA) specifically requested an assessment of nitrogen dioxide (NO₂) against AEGLs, with calculations required across three effect levels and five exposure periods ranging from 10 minutes to 8 hours. This posed two challenges: the absence of established UK regulatory guidance for AEGLs, and a tight deadline set by both the EA and the client, requiring rapid delivery without compromising quality or compliance.
Solution
Alkali Consultants deployed their in-house AEGL specialist, applying ADMS dispersion modelling software to calculate NO₂ AEGL concentrations (ppm) at 40 sensitive receptors surrounding the proposed data centre. Close collaboration with the client ensured the EA's requirements were fully addressed at each stage. By combining international best practice with rigorous modelling, Alkali Consultants demonstrated the flexibility to meet regulatory demands beyond conventional UK frameworks.
Outcome
- All five time-period objectives for NO₂ AEGLs were achieved.
- The highest 10-minute concentration recorded was less than 50% of the lowest Level 1 guideline, confirming compliance with significant safety margins.
- The project was delivered on time, enabling planning permission to progress without delay.