Table 3 USEPA Acute Exposure Guideline Levels (AEGL1-3) and New Zealand (Land Air Water Aotearoa 2023) and international (WHO 2021; US EPA 2023) guideline levels for SO2 concentrations (µg/m3)
From: Modeling SO2 dispersion from future eruptions in the Auckland Volcanic Field, New Zealand
| Â | Â | Exposure period | |||||
|---|---|---|---|---|---|---|---|
10Â min | 30Â min | 60Â min | 4Â h | 8Â h | 24Â h | ||
USEPA Acute Exposure Guideline Levels | |||||||
 AEGL-1 (Level 1) | Notable discomfort and irritation, effects non-disabling, transient and reversible when exposure stops | 520 | 520 | 520 | 520 | 520 |  |
 AEGL-2 (Level 2) | Irreversible or other serious long-lasting health effects | 2000 | 2000 | 2000 | 2000 | 2000 |  |
 AEGL-3 (Level 3) | Life-threatening health effects or death | 79,000 | 79,000 | 79,000 | 50,000 | 25,000 |  |
WHO and NZ Regulatory Guidelines | |||||||
 WHO 2021 Short-term SO2 guidelines | 500 |  |  |  |  | 40 | |
 NZ NES-AQ lower |  |  | 350 |  |  |  | |
 NZ NES-AQ upper |  |  | 570 |  |  |  | |
 NZ NAAQG |  |  |  |  |  | 120 | |