Thread by @DrTELS

So I spent yesterday evening having a quiet night in. At around 11 pm I began to smell smoke *inside my flat*.
I went out to investigate…

This is a somewhat angry (but evidence-based) wood-burning thread.
*trigger warning* for urban wood-burners!

#WoodBurning 🔥💨🧵 [1/n]

I live in inner-London (@LBHF). My flat is offset from a road by a building & car park, & gardens on the other side. All my windows & doors were closed. Below an air vent in my bedroom, I measured 34 µg/m3 of PM2.5 (close to unhealthy).
So I left my flat to investigate...
[2/n]

@LBHF I had a very good idea where this smoke was coming from. After a short walk upwind from my flat, I headed to the pub on the opposite side of the road from my estate (& not for a pint!) They were burning wood on an open fire. This is illegal (more details below).
[3/n]

@LBHF To start with, it's an offence to emit smoke from a chimney in 'smoke-control areas' (all of @LBHF). Smoke isn't always visible, but this illegal fire was producing obviously thick smoke, billowing from the pub's chimney towards council flats & student housing opposite.
[4/n]

@LBHF In front of the council flats & student accommodation, the sensor measured PM2.5 at 60 µg/m3 (unhealthy for everyone, increasing risk of aggravation to the heart & lungs). On the walkway in front of my flat it was 45 µg/m3 (unhealthy for sensitive groups, e.g. asthmatics).
[5/n]

@LBHF I'd overstayed my welcome in the pub after covertly taking photos & then asking to talk to the manager (who wasn't there), so I couldn't take a reading inside. Outside, a measurement from an air vent to the pub was 72 µg/m3 (unhealthy). It must have been higher inside.
[6/n]

@LBHF The rules about what you can & cannot burn, & in what appliances, aren't well-communicated. However, once you find them, both @DefraUKAir & the council's websites state that wood must be burned in 'exempt appliances' (e.g. a Defra-approved log burner), not on open fires.
[7/n]

@LBHF @DefraUKAir The open fire in this pub emits ~4,000x more PM2.5 than a gas boiler (per MWh energy produced), equivalent to almost every dwelling (4,910) in my council Ward (Ravenscourt Park) & 22x more polluting than the 180 gas-heated flats on my estate *combined* (downwind today).
[8/n]

@LBHF @DefraUKAir I will be complaining to the @LBHF Air Quality Team, my local councillors (@lizcollins777 & @walshpatrick95), & my MP @andyslaughtermp (AGAIN). *Again*, because this is not the first time that I've complained about the pub (see this email from February, this year).
[9/n]

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp I know it's the festive season & I don't want to be a Grinch, but the height of the chimney is below that of the housing opposite. In the flat above me is a toddler with asthma, & the people working in the pub will have chronic exposure to a known carcinogen.
[10/n]

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp Domestic wood burning accounted for 25% of UK PM2.5 emissions in 2020. This has increased by 35% between 2010 & 2020. It is now the single-biggest source of small particle air pollution in the UK, exceeding that of road traffic.

[11/n]london.gov.uk/programmes-and…

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp Some technical details: The sensor I'm using is pretty accurate according to a comparison with regulatory-compliant monitoring equipment (I'm a co-author on this open-access paper led by @DrKrisChan in which we evaluate the sensor hardware):

[12/n]journals.sagepub.com/doi/full/10.11…

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan This table helps to compare the measurements on my device in the photos (in micrograms of PM2.5 per cubic metre, µg/m3) with the US Air Quality Index & associated health risks. *There is no safe level of PM2.5*, hence my concern for the 34 µg/m3 in my flat.
Source: @IQAir
[13/n]

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan @IQAir Even legal Defra-approved burners using approved fuels emit 465x more PM2.5 per MWh than gas boilers. One house (& there is at least one) upwind of my estate can emit twice as much PM2.5 than the combined emissions from all 180 flats on my estate!

[14/n]

https://twitter.com/DrTELS/status/1588570235191595008

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan @IQAir I'm glad some councils and MPs are considering the issue, especially now that solid-fuel burning in a relatively small number of households is the single-largest source of particulate pollution in the UK.
@RuthNewportWest @AdamDKHarrison

[15/n]

https://twitter.com/RuthNewportWest/status/1669347713840984068

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan @IQAir @RuthNewportWest @AdamDKHarrison Domestic sources of PM2.5 in cities were all-but eradicated by the Clean Air Act 1956 & the transition to gas/electric heating in the 1960s/70s. This regressive trend for (arguably unnecessary) wood burning in urban areas is negating that progress.

[16/n]

https://twitter.com/DrTELS/status/1622324874214625285

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan @IQAir @RuthNewportWest @AdamDKHarrison Finally, wood-burning is not a 'green' alternative to fossil fuels. Burning wood rapidly releases CO2, when the wood carbon might otherwise slowly decompose or be stored. It's also less carbon-efficient than other energy sources:

@dsawsp
[17/17]dsawsp.org/environment/cl…

@LBHF @DefraUKAir @Lizcollins777 @walshpatrick95 @andyslaughtermp @drkrischan @IQAir @RuthNewportWest @AdamDKHarrison @dsawsp I'm fairly sure you will be interested in this thread:
@mwt2008 @GeorgeMonbiot @DrGaryFuller @kschrekenberg1 @jksmith34 @ndrlee @fionaharvey @CarolineRussell @Sefi_Roth_ @techpoodle @FedUpWithBadAir @cleanairforall2 @woodburningldn @cleanairdayuk @anotherjon @jimmcquaid

Thanks for the supportive replies. I'm learning to ignore the semi-abusive & ignorant ones. Many asked about the sensor & how to get one. It's a Xiaomi Smartmi PM2.5 detector. It used to retail for ~$30
@AliexpressGl, but harder to find at that price now:
onbuy.com/gb/p/new-smart…