Air quality at Rideau smelly station good, documents say


The tests were done on a single day, February 6. The newspaper obtained a copy of the results through an access to information request.

Air quality tests at Rideau Station, the source of a rotten egg smell that causes nausea and headaches in some LRT passengers, have only deepened the mystery of what does not go to the deepest station in the system.

The tests, carried out by a professional firm, show no problem in the air of the station. Not at all.

In particular, Buller Crichton Environmental found no trace of gaseous hydrogen sulfide, which is generally the source of a small rotten egg.

The tests were done on a single day, February 6. The newspaper obtained a copy of the results through an access to information request.

The tests were done at a time when the smell of rotten eggs was still relatively new. There had been a smell of sewage underground, especially at Parliament station, since the opening of the LRT.

But reports of rotten eggs arrived later, suddenly starting around the beginning of February. In addition to causing nausea, the smell raised the possibility of hydrogen sulfide gas, which is toxic to humans if levels rise high enough.

Hydrogen sulfide problems are not common in this region. They are often associated with natural gas production in Alberta and Saskatchewan. But gas can also come from decomposing organic matter, and downtown Ottawa suffered numerous spills and landfills of waste early in the city. Gas is heavier than air and collects in basements, sewers, and other underground spaces.

In addition to finding no hydrogen sulfide, the February 6 test found almost none of a wide variety of fumes called volatile organic compounds.

This group includes everything from natural gas and gasoline fumes to glue, paint, paint stripper, pesticides, many cleaning products and scented products.

The test excluded these items dramatically. The target level for volatile organic matter is to keep it below 400 parts per billion in indoor air. The average at Rideau was only 1.2 parts per billion.

The company tested flammable or explosive vapors and found no traces.

In addition, oxygen and carbon dioxide levels were good, indicating that the station is getting a good supply of fresh air from the ground. And there was no carbon monoxide, which indicates that no combustion smoke was leaking into the station.

The test sites included the platform, two halls and the entrance to Williams Street.

A public transportation commissioner wonders if a single day of testing is enough.

“Although I am pleased that the City finally listened to public concerns and tested the air quality in the LRT tunnel, I am disappointed that the tests were limited to one day,” said Sarah Wright- Gilbert in an email.

“As a person who crosses this tunnel twice a day, I can attest that the smell in the tunnel is not always of the same intensity. Single day tests cannot, in my opinion, provide accurate results. I would like to see RTG and the city perform air quality tests over a period of time to show a range of readings for a more accurate picture, so that the public can be sure their health and safety are not at risk . “

David Miller, professor of chemistry at Carleton University, says that hydrogen sulfide is a gas that some people can smell even at levels too low to be detected by standard instruments. (The Skunk spray is another, he said.)

The level they can sense “is far below OSH (Occupational Safety and Health) guidelines and any reasonable technology that a company could use would not detect exposures around certain people’s odor threshold,” writes- he.

Miller is a member of the American Industrial Hygiene Association, which studies environmental risks in the workplace, including air quality.


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