Dust issues are exacerbated under dry, windy conditions, so trigger levels for wind and rain conditions are also provided. Table 4: Suggested trigger levels for total suspended particulate (TSP) Sensitivity of receiving environment* Trigger Averaging period High Moderate Low Short term 5 min 250 µg/m3 n/a n/a Short term 1 hour 200 µg/m3 250 µg/m3 n/a Daily** 24 hours (rolling average) 60 µg/m3 80 µg/m3 100 µg/m3 Wind warning 1 minute 10 m/s (during two consecutive 10-minute periods) Rain warning 12 hours There has been no rain in the previous 12 hours Visible dust Instantaneous Visible dust crossing the boundary * In general, all residential areas will be high sensitivity (refer district plan provisions or table 2). ** For managing chronic (ie, long term) dust only Table 5: Suggested trigger levels for PM10 Sensitivity of receiving environment* Trigger Averaging period High Moderate Low Short term 1 hour 150 µg/m3 n/a n/a * In general, all residential areas will be high sensitivity (refer district plan provisions or table 2) 3.1.4 Trigger levels – deposited dust Table 6 provides a recommended trigger level for deposited dust. Table 6: Recommended trigger levels for deposited dust Trigger Averaging period Trigger levels (above background concentration)* Monthly 30 days 4 g/m2/30 days * Refer The deposited dust trigger level may not be appropriate for all circumstances. For example, some industrial or sparsely populated areas may not be troubled by deposition rates of more than 4g/m2/30 days above background levels. Conversely, some highly sensitive residential areas may find deposition rates of 2g/m2/30 days (above background levels) objectionable and offensive. It should also be noted that the nature of the dust may also be relevant to the dust deposition trigger level that is appropriate. Highly visible dust, such as black coal dust, will cause visible soiling at lower concentrations than many other dusts. The recommended trigger level for deposited dust normally applies to insoluble matter. This is because dissolved material is not significant when assessing nuisance effects from the majority of dust sources. However, consideration should be given to including analysis of water soluble emissions where these may be the cause of nuisance dust effects, for example particle emissions from a pulp and paper mill, milk powder plant, or fertiliser works.
Dust issues are exacerbated under dry, windy conditions, so trigger levels for wind and rain conditions are also provided. Table 4: Suggested trigger levels for total suspended particulate (TSP) Trigger Averaging period Sensitivity of receiving environment* High Moderate Low Short term 5 min 250 µg/m3 n/a n/a Short term 1 hour 200 µg/m3 250 µg/m3 n/a Daily** 24 hours (rolling average) 60 µg/m3 80 µg/m3 100 µg/m3 Wind warning 1 minute 10 m/s (during two consecutive 10-minute periods) Rain warning 12 hours There has been no rain in the previous 12 hours Visible dust Instantaneous Visible dust crossing the boundary * In general, all residential areas will be high sensitivity (refer district plan provisions or table 2). ** For managing chronic (ie, long term) dust only Table 5: Suggested trigger levels for PM10 Trigger Averaging period Sensitivity of receiving environment* High Moderate Low Short term 1 hour 150 µg/m3 n/a n/a * In general, all residential areas will be high sensitivity (refer district plan provisions or table 2) 3.1.4 Trigger levels – deposited dust Table 6 provides a recommended trigger level for deposited dust. Table 6: Recommended trigger levels for deposited dust Trigger Averaging period Trigger levels (above background concentration)* Monthly 30 days 4 g/m2/30 days * Refer The deposited dust trigger level may not be appropriate for all circumstances. For example, some industrial or sparsely populated areas may not be troubled by deposition rates of more than 4g/m2/30 days above background levels. Conversely, some highly sensitive residential areas may find deposition rates of 2g/m2/30 days (above background levels) objectionable and offensive. It should also be noted that the nature of the dust may also be relevant to the dust deposition trigger level that is appropriate. Highly visible dust, such as black coal dust, will cause visible soiling at lower concentrations than many other dusts. The recommended trigger level for deposited dust normally applies to insoluble matter. This is because dissolved material is not significant when assessing nuisance effects from the majority of dust sources. However, consideration should be given to including analysis of water soluble emissions where these may be the cause of nuisance dust effects, for example particle emissions from a pulp and paper mill, milk powder plant, or fertiliser works.
good-practice-guide-dust-2016.docx