Posted By: djhLegislation can help sometimes but not everywhere, short of an outright ban.

Existing legislation is not enforced properly (lack of resources and the will to enforce. e.g at http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9305&page=56#Item_7 ) so IMO proper enforcement of existing regs would help a lot

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Posted By: ListysDadIf you read the original report, it relates specifically to 'wet' wood being burned

Do you have a reference for this statement?

In paragraph 5 the guardian article says:
'... people in the study used only dry, seasoned wood.'

https://www.theguardian.com/environment/2020/dec/18/wood-burners-triple-harmful-indoor-air-pollution-study-finds

Interesting report! Good to see that pm2.5 emissions are now less than 20% of the 1970s levels and still falling a little.

But as we discussed further up the thread, most PM2.5s floating around in the air of most of the UK are not actually due to those primary manmade emmissions from the UK, such as woodburning, which are covered by that report.

Mostly they are
-natural (seasalt, desert dust, volcanoes, forest fires etc)
- manmade outside the UK (industrial and agricultural emmissions from Europe that drift over SE England)
- photochemical (NOx and Ammonia emmissions that react in sunlight to make PMs)

(Edit to add: I see this is completely lost on the Guardian environment reporters)


This report shows actual air quality measurements including all the above sources. Good news that:
"All [43 zones in the UK] met both limit values for annual mean concentration of PM2.5 particulate
matter: the Stage 1 limit value, which came into force on 1st January 2015, and the
indicative Stage 2 limit value which must be met by 2020.
https://uk-air.defra.gov.uk/library/annualreport/viewonline?year=2019_issue_1#report_pdf

Graphs show that pm2.5 levels are improving in all the urban areas that are reported, and all are safely within the WHO health limit.

Overall I think that air quality in the UK is in a pretty good state, which is a good news story so doesn't get reported much in the press. However people tend to talk about air quality as a distraction from other environmental issues, such as global warming and habitat loss, which need a lot more effort.

I bought a cheapie pm2.5 meter, and tried it in a few places. All numbers are in ug/m^3. The unit says that it excludes small particles and large ones, just shows the pm2.5:

Indoor 0-2
Indoor making nicely browned toast 0-2
Wood burner gets a firing for science 0-2 indoor (dunno outdoor though)
Indoor making slightly blackened toast, just at the edges (not as bad as when you scrape the black off) 50
Indoor frying pan, oil, stirring continuously, just softening onions 10
Indoor frying eggy bread a lot, extractor fan on, 100-200
Quiet (1 car per 20 seconds) road in Cambridge 5
Bus/truck passing on the other side of the road 10
Active roadworks (cutting tool, diesel digger) 15

It seems that anything that gets burned or looks blackened or smells a bit burnt makes the numbers shoot up. Frying with enough oil reduces the little blackened bits and keeps the numbers much lower. After the eggy toast experience, it took an hour to get down to normal background levels - even though we have MVHR.

I do love these home-grown experiments, however approximate, to give an order-of sense of scale to tech-based issues of the day.

Just wish we could do simple tests on air permeability of OSB, vapour permeability of EPS etc - just as it's easy to try sucking air through a material, membrane etc, using the very strong vacuum that your mouth can create, and which is easily calibrated by the height of water column it can suck up a 'drinking straw' tube.

Nice one Rob!
For context the WHO safe health limit is a daily average of 25ug/m3 and an annual average of 10ug/m3. So you can fry eggy bread continuously for a maximum of 3-6 hours a day before you should worry about your health...! But you can burn your woodburner continuously.


Tom, that was the Graun article I meant when I said " as we discussed further up the thread, most PM2.5s floating around in the air of most of the UK are not actually due to primary manmade emmissions from the UK, such as woodburning....I see this is completely lost on the Guardian environment reporters”

However their real agenda may have slipped out a little! ”half of those burning [wood] were affluent”

Posted By: WillInAberdeen
Tom, that was the Graun article I meant when I said " as we discussed further up the thread, most PM2.5s floating around in the air of most of the UK are not actually due to primary manmade emmissions from the UK, such as woodburning....I see this is completely lost on the Guardian environment reporters”

From the report:
13% sea spray.
about a third brought in from EU (and you can safely assume the UK "exports" a fair bit as well)
Half of the total is man-made in the UK. The guardian article is roughly correct.
Because all other sectors make serious efforts to reduce PM2.5, woodburners now are the single largest contributor, easily larger than the sea spray contribution.
Of course I agree that habitat destruction etc need attention, but that is not to say we should not make an effort to reduce PM2.5 from burning wood. The more research is done on the subject, the more it turns out that PM2.5 and smaller are really harmful. In that light, I can imagine sea spray having far less nasty effects than the PM2.5 from wood burning.

Our hob is induction.
Outdoors in leafy Cambridge suburbs the meter just now claims 0-2ug/m^3 pm2.5
It can clearly detect a match being lit, and it doesn't like candles (Mrs RobL not happy about that)

This is what I have by the way (temp & RH on it are useless due to selfheating, I did say it was a bit cheap):
https://www.banggood.com/PM2_5-Air-Quality-Monitor-Digital-Gas-Analyzer-Laser-Duty-Sensor-Air-Detector-Home-LED-Display-Temp-And-Humidity-Test-Equipment-p-1593795.html?utm_design=18&utm_email=1611019523_2324&utm_source=emarsys&utm_medium=Shipoutinform190813&utm_campaign=trigger-logistics&utm_content=leander&sc_src=email_2671705&sc_eh=980627074301d15b1&sc_llid=27252578&sc_lid=104858042&sc_uid=sEFTM2SqmW&cur_warehouse=CN

A few more interesting pm2.5 readings I took with our sensor (£30 banggood, see above for others):
Outdoors, slight tinge of woodsmoke 20ug/m3
In garage, activated carbon filtered recirc fan, soldering, thin flux cored solder 50ug/m3
As above, different solder, 999ug/m3

Yes, I was shocked with that 999 result- it maxed out the display. I have quaranteened that particular reel of solder wire, it is now for outdoor use only. That solder is a1mm reel, although I'm sure its the particular flux in it that is the issue- it says ersin 361. The thinner reel i have for SMT is much lower pm2.5, with no obvious downsides, it is Sn/Pb too, and says Rosin activated flux.
In general soldering should be done window open!

Sounds good. In fact invaluable!

Posted By: jms452keep somewhere vaguely stable in terms of temperature and RH (i.e. inside) and note down average temp & RH

You mean note down temp and RH both inside and outside the tank, thus the difference (gradient across the EPS)? And what - compare that with daily loss of weight of tank (i.e rate of water evaporated out)?

Basically a noddy version of this:

http://en.labthink.com/en-us/literatures/an-outline-of-standard-for-cup-method-water-vapor-permeability-testing.html

That's the way to get a good numerical answer

You might just prefer to have two (or more) fishtanks, with EPS on one and another material on the other - woodfibre, mineral wool, breather membrane, etc. Don't bother logging data, just check after a week which one has lost its mass of water, a) at all, b) the fastest.

Use buckets if you have no fishtank.

Post us a picture of your experiment!

Oxford have just come out urging residents not to burn wood as they emit harmful polluting particulates

Interested that this is a campaign with the Canal and River trust. People who live aboard canal boats have few cheap alternatives for heating, either diesel or bottled LPG, and not so much storage for seasoning firewood, so it must be tempting to burn firewood from the riverbanks.

Was slightly alarmed that they "aim to highlight particulates .... including the use of gas heating and cookers as well as solid fuel stoves". I've never really thought about particulates from gas heating, but I suppose there must be some. Domestic boilers and cookers don't have any exhaust treatment.

As previously, they are focusing on those particulates which are already in particle form at the moment they are emitted. Most particulates actually start out as gases (NOx SOx and ammonia, from exhausts and agriculture) which get turned into particles by sunlight.