Appendix 6. Odour Buffer Assessment [As Published] · 132007.2399

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              Odour Buffer Assessment
              StarCo Developments


causes annoyance, a reduction of say 50% may lead to only a marginal change in perceived
strength or intensity.



3.1.3      Duration

The duration of odour events is controlled mainly by meteorological conditions, although variations
in odour emissions may also be important for sources that vary in strength over short time periods.
Longer duration odour events are likely to be associated with more stable meteorological
conditions, which tend to be common at night and around sunrise and sunset. Somewhat
persistent odour events appear to be generally more likely to cause annoyance than very brief
single exposures, although this may simply reflect the general distribution of types of odour
sources (which have different types of impacts). Desensitisation or habituation can occur during a
substantial period of continuous exposure.



3.1.4      Offensiveness

Offensiveness is a subjective or qualitative aspect of an odour, relating to its intrinsic
pleasantness/unpleasantness or underlying quality. The offensiveness of an odour generally
increases as its strength increases.



3.1.5      Location

Location is an essential consideration when assessing the likelihood of odour nuisance. Greatest
emphasis is placed on ‘sensitive’ locations such as residences, schools, hospitals, recreation areas
and so on. People working within industrial environments are generally expected to be less
sensitive to odours than people within their home environment, but this assumption is increasingly
being challenged by practical examples of workers offended by odours from other enterprises. For
example, a person working in an office with no odour-generating activities will probably expect to
work in a low-odour environment. There are some less straightforward situations: for example,
people travelling past odorous activities may consider the odour to be unacceptable, even though it
is not impinging upon their residential property or workspace. This is an area that is not well
resolved in terms of assessing the validity of complaints about odorous activities, but odour
assessment generally places greatest emphasis and importance on odours at residential and other
sensitive sites.



3.2 Quantitative odour descriptors

Key elements of quantitative odour criteria that are used for planning purposes are:

                   Concentration

                   Averaging time and

                   Percentile value

Concentration is the odour strength (in odour units) as determined by dynamic olfactometry.




1898a report final.doc                                                   PAE Job Number 1898a