[Enthalpy]

Hello everyone and everybody!

Topic about the fire at Notre-Dame de Paris here.

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What is the yellow smoke on the pictures of the fire? Appended here is a reduction from
https://commons.wikimedia.org/wiki/Category:2019_Notre-Dame_de_Paris_fire#/media/File:NotreDame20190415QuaideMontebello_(cropped).jpg
other pictures show the yellow smoke clearly too:
https://www.forbes.com/sites/nicolemartin1/2019/04/16/digital-scans-and-data-could-help-restore-notre-dame-after-fire/
https://news.sky.com/story/notre-dame-eur600m-raised-to-help-restore-fire-damaged-paris-cathedral-11695462
https://www.vox.com/world/2019/4/15/18311852/notre-dame-cathedral-fire-spire-collapse-photos-pictures-paris-france
https://www.ndtv.com/world-news/will-rebuild-the-epicentre-of-our-lives-macron-on-notre-dame-fire-2023641

The colour resembles lead oxide PbO
https://en.wikipedia.org/wiki/Massicot
https://fr.wikipedia.org/wiki/Oxyde_de_plomb(II)
and Notre-Dame's roofing was made of lead.

What do you think? Thanks!

[Enthalpy]

Trying to estimate the lead concentration sent in the air by the fire...

Smelter workers had (in some places, have) harmful amounts of lead in the body due to lead's vapour pressure. If melting pure lead at 601K, the (equilibrium) vapour pressure is 10^-11atm. If bronze molten at 1210K contains 10%Pb, the lead vapour pressure is 10^-4atm.
https://en.wikipedia.org/wiki/Vapor_pressures_of_the_elements_(data_page)

In Notre-Dame's fire, the lead roofing melted around 600K, but the drops that landed on the burning oak beams didn't leave the flames. At 1400K, lead vapour pressure is 10^-2atm. In addition, liquid or gaseous lead in the flames made oxides that went in the atmosphere as fumes, in amounts not limited by the vapour pressure. To my opinion, this is probably the yellow smoke that I never saw over a wood fire.

The firefighters may have inhaled noxious amounts, especially those who climbed in the towers. The nearby inhabitants downwind too. Inhabitants farther downwind and by-passers maybe; the smoke didn't fall down immediately, according to the pictures.

I consider prudent that all people who smelled the smoke clean the clothes they wore, and clean with a vacuum cleaner all surfaces of rooms whose window was open.

Some study mapping the amounts would be urgently needed, diagnosis in the firefighters' blood more so. Treatments to lead poisoning exist
https://en.wikipedia.org/wiki/Lead_poisoning

[wildfyr]

How is it possible to get this concern to relevant health authorities? Or find out if it's already being addressed?

[Borek]

Yellowish smoke is not something unusual during fire, so I wouldn't search for too elaborate explanations without additional knowledge.

Actually I was surprised by how light the smoke was, I was expecting much more black one, with lots of soot.

[Enthalpy]

How is it possible to get this concern to relevant health authorities? Or find out if it's already being addressed?

French authorities will do everything they can to hide any problem, and will act only under people's pressure. The proper way is to inform the public.

[Enthalpy]

Yellowish smoke is not something unusual during fire, so I wouldn't search for too elaborate explanations without additional knowledge.

Actually I was surprised by how light the smoke was, I was expecting much more black one, with lots of soot.

Stone-old dry oak burns cleanly. It go enough oxygen because the lead roofing melted quickly as the flames advanced. 5mm lead melting at 327°C in a big fire at >1000°C. A tin soldier doesn't last for long in a chimney neither, and 50m propagation in 1h leaves time.

I too wish I had more information, but:

• From French authorities we won't get any sensible one. That's an absolute constant over history, whatever the regime.
• The sooner poisoned people get a treatment, the better. Lead in the blood can be chelated, in the bones not.
• It seems unavoidable that lead went in the fumes. Some remained in the fire, and then the vapour pressure let it evaporate. Can something prevent it?
• There were >>100t lead as roofing, but 100µg in the blood are unhealthy. Many processes provide a path stronger than 10^-9.
• The roof materials weren't so diverse, from pictures before the fire. Oak and lead. Dry oak in chimneys doesn't make yellow fumes. β-PbO is yellow.

[Enthalpy]

How is it possible to get this concern to relevant health authorities? Or find out if it's already being addressed?

French authorities will do everything they can to hide any problem, and will act only under people's pressure. The proper way is to inform the public.

The NGO Robin des bois tells much the same as I do. The French secret police insults it as an answer and threaten to cut the subsidies. The same spooks who insult and defame anyone revealing in France that wind energy is cheap. Don't expect France to work like the Netherlands or Switzerland.

[Enthalpy]

I had said that the yellow smoke was lead oxide, it is known now that hundreds of metres around the cathedral are polluted by lead, even if newspapers still put "molten".
The dense smoke fell down as it cooled, as you can see it on the pictures. The first 100m are not the worse location.
I would have preferred to be wrong. Tons of lead powder spread over a city are a catastrophe. Newspapers begin to discover the cover-up by officials.

http://en.rfi.fr/france/20190718-paris-orders-clean-schools-near-notre-dame-over-lead-fears
https://www.france24.com/en/20190718-paris-orders-schools-near-notre-dame-cleaned-over-lead-fears
https://medicalxpress.com/news/2019-07-notre-dame-prompts-deep-schools.html
and the cited "investigation site" is nearly the only one in France that does more than pasting the AFP news
https://www.mediapart.fr/journal/france/180719/notre-dame-la-mairie-de-paris-passe-sous-silence-des-contaminations-au-plomb-dans-les-ecoles?onglet=full (in French, and pay)
some sites relay the information
https://www.nouvelobs.com/societe/20190704.OBS15446/notre-dame-de-paris-les-taux-de-plomb-au-sol-aux-alentours-explosent-les-compteurs.html (in French)
https://www.tellerreport.com/news/--notre-dame--worries-about-the-consequences-of-lead-pollution-.HJxrrbEhE.html

Between "10× some alert limit", "800× the legal limit", "child with lead levels in blood much higher than acceptable limits" and "astronomically high lead levels on adjacent roads, blood tests for children under 7 and pregnant women", the discrepancy is vast. I Emphasize that no "lead safe limit" exists.

[Corribus]

Too bad you can't take blood samples from a representative population in Paris and coordinate the data to where they were at the time of the fire. In seriousness, the long term health consequences of a lead roof the size of the one in Paris aerosolizing during the fire could be very bad.

[Enthalpy]

I can't take blood samples, the government won't, but other groups may.

What upsets me: I reacted that 3 days after the fire, other organisations about 2 days. It would have been the right time to clean the pollution and chelate lead in the blood of contaminated persons. But after 3 months, the lead oxide powder has largely entered the lungs of the inhabitants and visitors, and passed from the blood to the bones, from where removal is nearly impossible.

How much lead? The roof contained about 300t, but only a fraction evaporated in the fire. The whole lead melted and rained down. What fraction fell on wood, where the heat evaporated the lead, and the vapour made lead oxide carried in the atmosphere? Alas, the attic had a wooden floor above the stone arch, so whether this floor had disappeared before or after the roof melted decides the pollution amount.

If lead fell on the wooden floor, about all 300t lead went in the atmosphere. If the floor had disappeared first, only the lead falling on beams evaporated, which could be 10^-2 or 10^-3× the amount.

Anyway, the toxic concentration of lead in blood is about the same as for cyanide. If 0.3t cyanide had been injected in the atmosphere of a dense city, more people would worry about it.

[wildfyr]

https://www.npr.org/2019/08/20/752565861/notre-dame-repair-crews-are-back-to-work-but-paris-lead-concerns-remain

Looks like there has been research and watch dog groups keeping and eye on this, including particle and blood testing.

[Enthalpy]

The journalist took time to consult several sources and his text isn't obviously biassed by some interest. The phrasing doesn't even seek sensationalism. I'm impressed, this is rare.

[wildfyr]

NPR is a gold standard of Journalism

[Enthalpy]

A governmental health agency published a report on 19 July, including on page 30 a map made by the police of the lead deposits
https://www.iledefrance.ars.sante.fr/system/files/2019-07/DP-point-de-situation-Notre-Dame-de-Paris_0.pdf (20MB)
it's frightening. The units are really µg/m² and up to 1.3g/m² lead deposited.

I didn't find in the report when the measurements were made. I believe it was in July, after several rains had cleaned the surfaces.

The figures tell how much lead gets dissolved by HCl under conditions that simulate the digestion, which I believe is a small fraction of PbO. Though, at least Wiki tells "Inhalation is a major source"
https://fr.wikipedia.org/wiki/Saturnisme#Air_ambiant
so the poisoning of people present during the fire may be much worse.

Multiplying the area by the surface density, I get only 1kg deposited right around the cathedral and 2kg on two districts downwind. Though, intuition shouts that the big dense yellow smoke that escaped for hours contained much more PbO. The figures don't add up. Probably most lead oxide deposited farther downstream: excess lead was observed in the air outside Paris. And most lead went to the sewage before the measurements.

To illustrate 1g/m², I weighed dust after cleaning a room: 1.9g over 30m² is yuk, and this isn't poison. At the cathedral, they got nearly that amount on 1m². Pictures appended.

How unhealthy? Imagine that away from Notre-Dame, at Saint-Michel square that kept open and uncleaned, someone wanting to make photos lays his 0.02m² croque-monsieur on the foutain's rim, then eats it. 30mg/m² were measured (but when?), so he ingests 600µg of digestible lead equivalent. If he's an adult with 6L blood, his concentration climbs to 10 µg/dl, the upper limit set by the Center for Disease Control. On the cathedral's square, concentrations were 20* higher.

The concentration may have been much higher right after the fire, and poisoning over the lungs worse.