Are you RLW?

Air pollution – Chapter 2

How are you today? I don’t know about you, but personally, I am somewhat RLW – Running Low on Wood that is.

Which, in a nutshell, means “pretty fine for now, but in deep trouble soon if I don’t do something about it”.

As you drive through the surrounding villages, you can tell with a bit of experience which houses are likely to be RLW. They have thick smoke pouring out of their chimneys, which shows that the owners are burning wood they’ve recently collected, not wood they’d left to dry in a shed for at least three years, as their ancestors would have done.

A RLW neighbour of mine once assured me, as he was frantically splitting freshly collected timber to feed his starving stove, that he was only collecting “dry standing wood”. Sure. He knew I knew anyway…

Mind you, it does not mean that the type of people who carefully squirrel away wood and let it age have a smoke that you’d exactly call “clean”… Theirs just looks a bit less … well, smoky.

What do you mean, what about mine? I shall give it a miss … the picture was taken as I was away for the day.









Look, let’s be honest, when it comes to air pollution and PM10, the Chinese and Indians are small players really. The only reason we cannot score the numbers over here is that we are so few and far between. If we were anywhere near their population density, we would be lost in our own gardens without a compass, wearing emergency respiratory kits while unearthing potatoes for lunch.

Yes, let us face reality and do something about it.

This is what I like about my country: no matter how inefficient we are, we can talk about it openly, and tell other people what they should be doing.

Again, smart technology and cogent regulations are the winners of the day. We just need to enforce them ruthlessly. No mercy.

When it comes to wood furnaces and stoves, professional organizations in France, acknowledging the current shortcomings, established in 2000 the official “Flamme Verte” label for domestic as well as industrial wood-burning equipment.

“Flamme Verte” stands for “Green Flame”. No, you are not supposed to check online what stuff would emit green flames when thrown into your fire. No boric acid, no copper sulphate, please.

“Flamme Verte” is only a label, awarded to wood-burning appliances that meet certain efficiency and emissions criteria. It is not a mandatory performance standard.

In short, for my type of stand-alone domestic stove using natural wood, it reads:

Performance Rating Efficiency


Carbon Monoxide Emissions


Fine Particles Emissions

(mg / Nm3)

5 ***** > 70 0.30 90
6 ****** > 75 0.15 50
7 ******* > 75 0.12 40


As with everything technical, it can get … well, very technical: the carbon monoxide and particles emissions are measured according to the PR NF EN 16510 set of norms, which you can download from the official website for a few hundred euros.

Anyway, the beauty and the actual purpose of “labels” is that you do not have to do the measurements yourself. You can put your credit card back into your wallet. Professionals do the assessment for you, and you only have to check the rating of the appliance you are considering acquiring.

Interestingly, when it comes to air pollution, we can relate the emitted particles concentration ratings to the WHO Air Quality Guidelines:

Allowing for unknown variations and discrepancies of some parameters (temperature, pressure, particles size in the PR NF EN 16510 norm, …), the Flamme Verte 7-star class prescription is still 3 orders of magnitude, that is about 1,000 times higher than the WHO air pollution guidelines.

We are definitely on the right path, but we still have a long way to go. For now, do not channel the exhaust from your wood-burning appliance into your bedroom.