Archived report · 2 min read · Set in Ostrova ·
Chimney Smoke Direction at the Ostrova Works
An air-quality survey of the Ostrova works chimney finds the smoke leaving the stack on still mornings and flowing back down into the works yard, where it settles in the shape of a sleeping worker's outline on the cobbles.
- filed: Filed with the spring pollution return
- reference: AQ/OW/14
Subject: smoke discharge, main stack, Ostrova Works, boiler house.
1. The stack is 42 metres high and serves three coal-fired boilers, now converted to gas. It was last surveyed in 2019 and found to meet the emission limits set for the valley.
2. On still mornings, with wind speeds below one metre per second, the plume was tracked from the stack top using a theodolite and video. The plume normally rises vertically and disperses above the works roofline.
3. On the mornings of the 2nd, 5th and 9th of March, the plume did not rise. It descended. The smoke came down the outside of the stack in a slow, coherent column, reaching ground level at the base of the boiler house, and spread out across the works yard at a speed of approximately half a metre per second.
4. Air samples were taken from the yard surface. The composition of the smoke is consistent with normal combustion products. No toxic elements above background were detected.
5. The smoke collected in the lee of the wall on the east side of the yard, where it settled and remained for between eight and twenty minutes before dispersing. The surface staining left by the deposit was photographed.
6. The stain is not random. It forms a clear outline of a human figure lying on its side with the head resting on one arm, approximately 1.8 metres long, in the position that an employee on the night shift would adopt when resting in the yard shelter.
7. Recommendation: fit a draught damper to the stack and inspect the flue for obstruction. The damper was fitted on 14 March. The descending plume has not recurred.
8. Observation not explained by the survey: the stain on the east wall has not weathered. It has been cleaned three times and has returned each time, in the same position, slightly sharper, and the outline now has a small dark mark at the level of the hand that the survey team did not record in the original photographs.