A12-1 Comparison of International Odour Assessment Criteria / Guideline Value

A review of the odour impact assessment criteria adopted by other countries indicates that those more commonly used include a percentile component (varies from 99.5 percentile to 99.9 percentile). This contrasts with the 100% compliance criteria used in Hong Kong. In addition, most of these criteria stipulate an averaging time of 3-minute or 1-hour, contrary to the 5 second average used in Hong Kong. One of the reasons for other countries adopting the percentile values is that odour nuisance will only happen when odour exceedances are frequent enough to trigger complaints. As a reference to the evaluation of the residual odour impacts at the TKO Area 137 and TVB City, a selection of odour impact assessment criteria adopted in other countries are presented in Table A12.1a. It should be noted that the assessment of the residual odour impacts to the representative assessment points at TVB City and TKO Area 137 as presented in Table 4.9a is based on the 5OU over a 5-second averaging time criterion stipulated in Annex 4 of the EIAO-TM.

In order to review the predicted results for the Extension based on the percentile approach, the highest odour concentrations predicted at the representative assessment points of TVB City (A2) and TKO Area 137 (A1-3) are presented in 3-minutes and 1-hour averages and compared with the odour impact assessment criteria adopted by the overseas countries. The results are presented in Annex A12-2 and summarised in Table A12.1a. As can be seen, the predicted odour concentrations at TVB City and TKO Area 137 comply with most of the odour assessment criteria adopted by these countries except the odour criteria adopted by US for A1-3 (1).

Table A12.1a Comparison of Predicted Odour Concentrations at TVB City and TKO Area 137 with Overseas Odour Assessment Criteria or Guideline Values

Countries	Odour Concentration (OU m^-3)	% Time Compliance	Averaging Time	Critical Receptor Location	Predicted Highest 3–min Average Odour Concentration at ^(g) (j)		Predicted Highest 15-min/1-hour Average Odour Concentration at ^(g) (i) (j)		Remarks
					TKO Area 137	TVB City	TKO Area 137	TVB City
New South Wales, Australia ^(a)	2 (Stringent; Large population/ close to sensitive receiver)	99.9%	3-min	Residential	3.86	1.90	-	-	For A1-3 (1), there are 7 no. of exceedance of odour assessment criterion, which is 0.07% of time over a year which complies with the 99.9% tile criteria. The predicted 3-min average odour concentrations at TVB City are 100% compliance with the criterion.
Queensland, Australia ^(b)	10	99.5%	1 hour	Residential near piggery	-	-	2.95	1.45	The predicted 1-hr average odour concentrations at TVB City and TKO Area 137 are 100% compliance with the criterion.
South Australia ^(c)	4	99.9%	3-min	No. of people >350 but < 2,000	3.86	1.90	-	-	The predicted 3-min average odour concentrations at TVB City and TKO Area 137 are 100% compliance with the criterion.
New Zealand ^(d)	2	99.5% to 99.9%	1-hour	High sensitivity of the receiving environment (worst-case impacts during neutral to stable conditions)	-	-	2.95	1.45	For A1-3 (1), there are 7 no. of exceedance of odour assessment criterion, which is 0.07% of time over a year which complies with the 99.9% tile criteria. The predicted 1-hour average odour concentrations at TVB City are 100% compliance with the criterion.
UK ^(e)	1.5	98.0%	1-hour	Residential	-	-	2.95	1.45	For A1-3 (1), there are 7 no. of exceedance of odour assessment criterion, which is 0.07% of time over a year which complies with the 98% tile criterion.
US State of Oregon ^(f)	1 to 2	Highest	15-min	Plant Boundary	-	-	2.95	1.45	For A1-3 (1), there are 3 no. of exceedance of odour assessment criterion (2 OU), which is 0.034% of time over a year.
US, California ^(g)	20	<100 hours/ year non-compliance	-	Residential with highway	-	-	-	-	The predicted highest 5-second average odour concentrations at TKO Area 137 and TVB City comply with the 20 OU m^-3 criterion.
City of Calgary, Canada ^(g)	20	<100 hours/ year non-compliance	-	Rural with growing residential	-	-	-	-	The predicted highest 5-second average odour concentrations at TKO Area 137 and TVB City comply with the 20 OU m^-3 criterion.
Netherland ^(g)	3	98.0%	1-hour	Residential area or other sensitive receptors	-	-	2.95	1.45	The predicted 1-hour average odour concentrations at TVB City and TKO Area 137 are 100% compliance with the criterion.
Notes: (a) EPA 373/07 guideline (Odour assessment using odour source modelling) - http://www.odournet.com/legislation-.html (b) http://www.odournet.com/legislation.html (c) EPA Guidelines on Odour Assessment using Odour Source Modelling, Updated Apr 2007 (d) http://www.mfe.govt.nz/publications/air/odour-tr-aug02.pdf (e) A. P. Van Harreveld; www.env.go.jp/en/air/odor/measure/02_1_3.pdf (f) Mahin; http://www.env.go.jp/en/air/odor/measure/02_1_4.pdf (g) Final Report on Odour Management in British Columbia: Review and Recommendations, RWDI Air Inc, March 2005. (h) See Annex A12 for detailed calculations. (i) The modeling results will be representative for period between 1 hour to 15-minute averaging time. (j) The predicted highest 3-min average and 15-min/1-hour average odour concentrations at TKO Area 137 and TVB City were estimated based on the highest results predicted during Phase 1 for TKO Area 137 and during Phase 2 for TVB City.

Annex A12-2 - Estimation of 3-min and 15min/1-hour Odour Levels for A1-3(1) and A2
(a)	The highest 5-sec odour levels were predicted under stability class F at A1-3 (1) & A2. (Reference to Annex A11-1)
(b)	For converting 5-sec odour level to 3-minute odour level, a factor of 5 was used (reference to Warren Spring Laboratory, "Odour Control - A Concise Guide", 1980)
(c)	For converting 5-second odour level to 15-min/1hour odour level, a factor of 6.9 and 6.55 for stability class D & F, respectively, was used
	(reference to RA Duffee, "Odour Modelling - Why and How")
A1-3 (1) --- After Rephasing
Year	Month	Day	Hour	Temp	Wind Speed	Wind Direction	Stability Class	Phase 1
								5-sec	3-min	15min/1-hr
06	4	8	22	23	0.5	128	F	19.3	3.86	2.95
06	3	21	20	0	0.7	123	F	17.2	3.44	2.63
06	4	3	20	24	0.5	129	F	16.9	3.38	2.58
06	6	26	23	30	0.8	128	F	12.1	2.42	1.85
06	1	11	22	19	0.6	130	F	12.0	2.40	1.83
06	1	10	19	16	0.9	127	F	11.9	2.38	1.82
06	4	7	20	22	1.1	126	F	10.5	2.10	1.60
06	3	17	20	0	0.8	130	F	9.0	1.80	1.37
06	12	5	18	22	1	129	F	8.5	1.69	1.29
06	6	20	20	29	1.1	119	F	8.0	1.60	1.22
06	6	28	18	26	0.5	122	D	7.3	1.47	1.06
06	4	25	22	24	1.6	122	F	7.2	1.45	1.11
06	12	22	18	19	0.9	131	F	6.6	1.32	1.01
06	6	20	19	29	1.1	130	F	6.6	1.31	1.00
06	4	3	19	24	1	117	F	6.5	1.30	0.99
06	3	3	19	0	1.2	118	F	6.4	1.28	0.97
06	2	23	22	17	1.5	119	F	5.9	1.17	0.90
06	6	22	8	30	0.6	129	D	5.4	1.09	0.79
06	4	7	19	22	1.8	128	F	5.4	1.07	0.82
06	2	8	20	17	0.6	133	E	5.4	1.07	0.82
06	4	29	18	25	0.7	123	D	5.3	1.06	0.77
A2 (TVB City) --- After Rephasing
Year	Month	Day	Hour	Temp	Wind Speed	Wind Direction	Stability Class	Phase 1
								5-sec	3-min	15min/1-hr
06	1	28	22	16	0.7	147	F	8.9	1.79	1.36
06	1	13	19	19	0.7	144	F	8.4	1.69	1.29
06	6	21	20	29	0.6	150	F	7.9	1.58	1.21
06	6	12	20	26	0.8	145	F	7.8	1.56	1.19
06	5	27	22	27	0.9	144	F	6.6	1.31	1.00
06	12	22	23	16	0.9	149	F	6.0	1.20	0.92
06	3	20	20	0	1	144	F	5.9	1.18	0.90
06	1	16	21	20	0.6	152	F	5.5	1.09	0.83
06	12	4	18	21	1	149	F	5.4	1.08	0.83
06	6	2	20	27	1.2	147	F	5.2	1.04	0.80
06	6	26	20	30	0.5	139	F	5.1	1.03	0.78
Year	Month	Day	Hour	Temp	Wind Speed	Wind Direction	Stability Class	Phase 2
								5-sec	3-min	15min/1-hr
06	3	21	20	0	0.7	123	F	9.5	1.90	1.45
06	4	8	22	23	0.5	128	F	8.2	1.65	1.26
06	4	3	20	24	0.5	129	F	6.7	1.33	1.02
06	1	10	19	16	0.9	127	F	5.4	1.09	0.83
06	6	26	23	30	0.8	128	F	5.2	1.03	0.79
06	4	7	20	22	1.1	126	F	5.1	1.02	0.78