- Case Study - VOC and RSC Sampling at Downtown Fire Hall for an Odour Event. Introduction. Response: - Three-month monitoring during the winter 2010-2011. - Canister sampling when odour was perceived. Problem:
VOC and RSC Sampling
at Downtown Fire Hall for an Odour Event
- Three-month monitoring during the winter 2010-2011.
- Canister sampling when odour was perceived.
Occasional odour complaints during cold winter days when atmosphere is stable.
To investigate the potential sources of odours.
- Temperature: -17°C, increasing from midnight of -22°C.
- Wind: Low wind speed ~3-4 km/hr from SW direction.
- Upwind sources: CPR rail yard and downtown business/traffic
- SO2: 3 ppb, maximum of the day (baseline conc. <1 ppb).
- Locomotive diesel contains higher sulphur (max 500 mg-S/kg) than
on-road diesel fuel (max 15 mg-S/kg).
- Normal conc. pattern for the other pollutants (NOx, CO, THC, O3, PM2.5).
06:22 am: 3 ppb, max. of the day
- A grab sample was collected.
- 06:22 am January 31, 2013 when an odour was perceived.
- Sample was analyzed for
Reduced sulphur compounds (RSC), and
Volatile organic compounds (VOC).
- Small sample size, n = 1.
- Sample did not detect a unique signature species.
- Compare to the Mirror rail yard study (AESRD, 2011).
- Mirror is located approx. 50 km NE of Red Deer.
- Simple flat terrain, few emission sources near Mirror.
- The program collected both upwind & downwind samples.
- Rail yard activities information was recorded.
Nevis Gas Plant
4 km approx.
Nevis Booster Compressor
7 km approx.
– Typical sulphide odour, like a rotten egg smell
– Most abundant sulphur compound naturally present in atmosphere.
– Anthropogenic sources:
Upwind of rail yard
Downwind of rail yard, with active rail yard activities
Downwind of the south rail yard, but little activities in this section
- Detected in most samples (active & minimal yard activities)
- Conc. not apparently higher for samples with active rail yard activities upwind (B,C vs. D,E) .
- In Canada, vehicle emission accounts for >80% of benzene in an urban area.
- Traffic volume: City of Medicine Hat > Hamlet of Mirror
- Other petroleum fuel combustion is another potential source of benzene.
- Railyard operation might not be the sole emission source of toluene.
- Toluene is a naturally occurring component of crude oil and petroleum.
- Major anthropogenic sources in Alberta are O&G operation and cement manufacturing.
- Potential link with rail yard activities.
Butane & isobutane: refrigerant, aerosol propellant, fuel blending.
Freon-11: refrigerant, aerosol propellant.
Although low concentration, some species present a trend with wind pattern and rail yard activities.
Five species were detected in the samples when wind was from both active and less active rail yard.
Only methylcyclohexane was detected in the sample upwind of rail yard.