UKC

This is probably not the right forum for such a question, but you never know who reads this:

Out hiking today, my partner and I could smell a distinctly halogen-y note in the air around Calton (it would smell of chlorine to a layperson, more below*). The smell persisted half way down to the Hamps valley, and we could also smell it on our return from ca. half way up Musden Wood to the NE of Calton. There were strong southwesterly winds all day, and to be honest I found the strength of the smell a bit disconcerting. Given the dilution factor of such strong winds, the source would have had to be very close (hopefully), but even then...
Lafarge Cement/ Aggregate Industries & the Tarmac National Laboratory are the only industrial sites in the vicinity, but why on earth a cement manufacturer would release large amounts of halogen on a Sunday I don't know (I'm an inorganic chemist, but don't really know what would be banging about at the above sites).

Any clever ideas?

*I would not give it 100% on chlorine, it could also be bromine or a volatile halogen source such SOX2, BX3 or similar. It definitely wasn't the type of oxidising smell one might mistake for a halogen such as NOx or O3.

emergency water treatment?  We were told not to use our tapwater for anything other than toilet flushing last week for a couple of days because of excess chlorine in the water because of the storm

The nose is remarkably sensitive outdoors in the fresh air when it's not being bombarded with hundreds of other molecules and trying to ingore most of them, unless they smell dangerous or edible.

We live a few miles from Clitheroe cement works and when the wind is from that direction there's a strong smell, hard to describe but mostly sulphur dioxide. During the first big storm a week ago I went outside and noticed a strong odour of SO2 in the air, which is strange because between us and the Atlantic is Preston and Ireland and I'm not aware of any heavy industries in Preston. Somebody else, living in the Bristol area, mentioned it on Cycle Chat the following day so I wondered if we were picking up pollution from the American east coast. The wind must be flowing in almost a laminar way across the Atlantic at the moment, undisturbed by vortices. I emailed the Met Office but don't expect a reply.

One other possibility is that in Preston around the east side of the town there is often an unpleasant and distinctive chloriney smell, almost with elements of chocolate in it. We have tried to work out its source but one thing's for sure, which is that I used to smell exactly the same odour in Gosforth, Newcastle upon Tyne, when I lived there and I always understood that it came from a big pharmaceutical factory somewhere to the west. Maybe there's something like that near where you were walking?

That's a great idea! Would make a lot of sense, there was a huge amount of surface run-off everywhere, and Hamps & Manifold rivers in full spade. Water treatment plants may well struggle with containing contaminated water.


In reply to Rigid Raider:

Very interesting thoughts on air flow, could you post up in here if the Met Office ever get back to you? The only sites I am aware of that may carry out e.g. brominations are in the wrong direction (Notts and Manchester universities, Alderley Science Park, GSK Stockport, AZ Macclesfield, etc.).

There is a storm tank / foul sewer overflow right where the footpath up from Musden Wood joins Back Lane (NE of Calton).

https://goo.gl/maps/yqniyaxPBJ64rPJg9

If it was coming from the direction of a river, that's your answer. Sewage plants can only handle so much and in times of flood they overflow into the river. I remember finishing the Ride London 100 when it was shortened to 86 miles due to an American hurricane making landfall; riding along the Chelsea Embankment on drying roads there was a stink of fresh sewage from the Thames as the Victorian sewers overflowed. The new deep level Thames Tideway sewer is supposed to prevent that happening.

Yep, there's the likely culprit. Sewage treatment plant 'tucked' away in the Hamps Valley, west of Calton.

https://goo.gl/maps/coAQ3RF16ivKEJ4z6

Seems I was wrong about the Met Office, just received this email:

Thank you for your question.  You are correct that the airflow reaching the UK overnight on 9-10 February was strongly from the west and travelled rapidly over the North Atlantic and Ireland.  We have not been able to analyse the period in detail, but UK monitoring stations for sulphur dioxide do not show any unusual features from that time, and our air quality model does not show any increases in SO2 related to this air flow. Long-range transport of greenhouse gases from America has been recorded at UK monitoring sites, but we are not aware of any incidents of SO2 transport over this distance at the concentrations required for an odour to be detected.  Without further examination, we cannot rule it out though.

I Don't suppose you noticed any imported chicken?

Blimey, hats off to the met office for such a well-researched and detailed response. Impressive.