26th CASANZ (Clean Air Society of Australia & NZ) Conference 2022, Adelaide
Assessment of offensive odour risk in accordance with Environment Protection Authority of Victoria (EPA) Publication 1883 Guidance for assessing odour, June 2022 (EPA Publication 1883) is based on the downwind odour frequency (as measured in a field odour survey) multiplied by the annual wind frequency of that particular downwind direction (which can be sourced from wind measurements or from meteorological modelling). Show more…When odour presence is observed during calm conditions, the frequency of calm conditions replaces the wind frequency in assessing odour risk. By convention, a ‘calm’ is said to occur when wind speeds are less than 0.5 m/s, as this is a typical stall speed for older ‘cup and vane’ type wind instrumentation used in weather stations. However, if newer and more sensitive technologies such as ultrasonic wind sensors are used in the field, wind measurement can be more refined. Accuracy of measurement can be achieved to the level of 0.1 m/s and measurement starting threshold as low as 0.01 m/s. Hence, for assessing odour risk, the definition of ‘calm’ may need to change from convention as field experience corroborates that wind movement can still be physically detected below 0.5 m/s. This case study seeks to explore whether changing the definition of calm winds would affect the categorisation of offensive odour risk under EPA Publication 1883, and how this s may affect the type of wind data to be used for an odour risk assessment.Show less…
