Odour Sampling Methods for Point, Area, Fugitive, and Ambient Sources

There is still some confusion about standard sampling methods regarding odours. There are standard methods for specific contaminants such as particulate and volatile organic compounds, but there is no specific standard method, especially in the United States, for odour sampling. In Canada, there is a Draft Ontario Ministry of Environmental Method (Source Sampling for Odours, version 2, 1989), however this method is inadequate and the Ontario Ministry of the Environment is in the process of updating this method. Even European (EN13725;2003) and Australian/New Zealand (AS/NZS 4323.3:2001) odour standards do not specify their sampling methodology except in general terms, such as; using static or dynamic dilution for point sources sampling, flux hood method or wind tunnel methods for area sampling. These standards still allow static dilution and do not specify the number of samples collected per source, the sampling time, or any other important factors, which might affect the final results. These methods are designed more for odour evaluation than for odour sampling, and the results accuracy should be seriously questioned, when you consider that there is no set standard method for odour sampling.In the United States, sampling for odours is limited either to measuring ambient levels using a scentometer or other portable unit, or by sampling at point sources without dilution with a minimum number (sometimes one or two) samples per location/source. This paper will emphasize the following issues; the importance of dynamic dilution when sampling at point sources, especially when the source is hot and the odour lost during sampling can be up to sixteen times greater, when an appropriate method is not applied. The results for both the dilution technique and an undiluted technique will be compared and will show the loss of odorants when samples are not diluted. Secondly, this paper will compare two methods for sampling area sources and will compare the results obtained by sampling at area sources with both a Standard Flux Chamber and a Portable Wind Tunnel at the same source, and at the same time.A brief description of sampling for fugitive sources will be also introduced, but due to the complexity of sampling for fugitive sources, a separate paper is being prepared. This paper will also concentrate on sampling ambient odour levels using comparisons of an actual sampling downwind from a facility using the lung methodology. This method will be compared with those obtained from Nasal Ranger readings performed at the same time and at the same location.This paper will demonstrate the importance of proper sampling at point sources, area and fugitive sources or for ambient levels.