Odour Threshold Investigation 2012 - Bay of Plenty Regional Council

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The original concept behind the testing methodology was one of using an untrained panel of participants. However as the tests progressed panellists became well aware of what was required and the random nature of the presentation of gas along with the appropriate conditioning of the gas (e.g. no obvious temperature difference between the two ports etc.) at each olfactometer port was critical. It is reasonable to assume that during the testing the threshold value per panellist may have decreased as panellists become more attuned to the odour. In Figure 7.15 first and last round results are presented for a number of the Whakatāne panellists (where each panellist attended three sessions) there is visual evidence that some of the panellists are exhibiting this downward trend. There are however a number that show a trend in the opposite direction. No further analysis of panellist behaviour over sessions is undertaken at this time as a more rigorous and tailored methodology would be required to check the hypothesis of changes per panellist over sessions. Figure 7.15 Trends per panellist by comparing first and last round results. NZAAQ 7 µg/m 3 guideline analysis There is also the ability to investigate the percentages of the dataset which are below or above a value(s) of interest. For this exercise a value of 7 µg/m 3 has been chosen. With the plots shown in Figure 7.16 percentage results for any value of interest can be easily obtained. The chosen 7 µg/m 3 represents the current MfE guideline for odour annoyance. The percentage detection results show that most panellists in the Whakatāne and Rotorua groups are able to recognise the 7 µg/m 3 concentration, with >95% of the recorded detection values below this guideline. The Rotorua plot shows a slightly lower percentage of values at which this guideline was met. The third plot shows the results for the periods of testing in Rotorua where elevated ambient H 2 S 46 Environmental Publication 2012/06–A review of odour properties of H 2 S Odour Threshold Investigation 2012
concentrations were recorded within the testing room. These data points were removed from the earlier analysis (see Section 7.1.2). They show a pattern of a lower level of sensitivity whereby only 58% of the values were at or below the guideline. Whakatāne Group – round data Rotorua Group – round data Rotorua removed data Environmental Publication 2012/06–A review of odour properties of H 2 S Odour Threshold Investigation 2012 47
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A review of odour properties of H 2
Page 5:
Acknowledgements Dr Bruce Graham fo
Page 8 and 9: In relation to the second question
Page 10 and 11: 6.5 Equipment 29 6.6 Requirements o
Page 12 and 13: Figure 7.10 Graphical summary of th
Page 14 and 15: The standardisation of DDO in Austr
Page 16 and 17: Figure 2.1 Odorant receptors and th
Page 18 and 19: Figure 2.3 Relative slope of odour
Page 21: Part 3: H 2 S health effects The pr
Page 24 and 25: such as composting can provide very
Page 26 and 27: Seigel et al 32 undertook measureme
Page 28 and 29: Rotorua District Council also under
Page 30 and 31: Kevern 56 undertook several surveys
Page 33 and 34: Part 5: H 2 S threshold information
Page 35 and 36: The American Industrial Hygiene Ass
Page 37: Earlier summaries of data in relati
Page 40 and 41: The results generated by the olfact
Page 42 and 43: At each round of the testing proces
Page 44 and 45: 6.7.2 n-Butanol vapour The standard
Page 46 and 47: 7.1.2 Ambient H 2 S levels No H 2 S
Page 48 and 49: Residence time for Rotorua panellis
Page 50 and 51: Figure 7.7 Example of incomplete ro
Page 52 and 53: A display of the “round” values
Page 54 and 55: Figure 7.11 Log 10 mean session dat
Page 56 and 57: Panellist means Figure 7.12 t-test
Page 60 and 61: Figure 7.16 Frequency plots - perce
Page 62 and 63: Figure 7.17 Scatterplot showing n-b
Page 64 and 65: Several types of analysis of the gr
Page 66 and 67: Figure 8.1 Updated H 2 S threshold
Page 69: Appendix 1 - Olfactometer calibrati
Page 73 and 74: Appendix 3 - Dr Ray Littler analysi
Page 75 and 76: Effect of elevated ambient H 2 S On
Page 77 and 78: Figure 4 Untransformed is non-norma
Page 79 and 80: 14 Histogram of MnH2S_Whakatāne 12
Page 81: Histogram of Mn butanol Lognormal R
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Odour Threshold Investigation 2012 - Bay of Plenty Regional Council

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