Wildfire smoke

The card is short and its one rule, never wait once a warning is issued, is the correct rule. This is the British shape of the problem, which is different from the American one the phrase wildfire brings to mind.

British wildfire is not the picture in your head

Here it is grass, gorse, heath, moor and shallow peat, not a wall of burning conifers. That changes the tactics in two ways.

Grass fires move faster than forest fires under the same wind. There is less fuel, so less heat, and the flame front travels quickly over open ground with nothing to slow it. The moor that looked static from the road can cross a field in a few minutes.

And fire climbs. Uphill spread is dramatically faster than on the flat, because the rising heat dries and preheats the fuel above. So the rule is never to be uphill of a fire, and never to run uphill from one. Move across the slope and downhill, toward a road, a river, a car park, ploughed ground, or anything already burnt.

Smoke reaches far beyond the fire. Most British households will meet the smoke and never the flame, which is what the rest of this page is about. The same applies to smoke from a large building or industrial fire nearby, which is the more likely urban version.

The mask does one job only

FFP2 and FFP3 respirators filter fine particulates, and that is genuinely worth having. They do nothing at all about carbon monoxide, or about the other gases in smoke.

So a mask is for the smoke plume drifting over your area, not for being near a fire. Nobody should be relying on a mask to spend time in heavy smoke, and nobody should be indoors with a burning appliance thinking a mask helps, because it does not.

Fit is most of the performance:

• It must seal against skin. Facial hair at the seal drops the protection substantially.
• Both straps, over and under the ears, not looped on one.
• Mould the nose bar properly, which is the leak most people leave open.
• They are not made for small children. There is no properly fitting respirator for a young child, which means the answer for them is a clean indoor space rather than a mask.
• Valved masks protect the wearer and not others, which matters in the pandemic card rather than this one.

Anybody with asthma or a heart or lung condition should be indoors with the windows shut, using their preventer as prescribed and keeping their reliever with them. Smoke is a recognised trigger, and the deterioration can be rapid.

The clean air room, cheaply

The card says seal into one room and lay wet towels at the gaps. Two additions make a real difference.

A box fan with a filter taped to the back is the cheapest air cleaner that works. A standard domestic fan, a decent pleated filter across the intake, taped at the edges so air cannot bypass it, running in the room where people are. It costs a fraction of a purpose-made purifier and does most of the same job for particulates.

Then the rest of the room:

• Windows and doors shut, gaps sealed with damp towels along the bottoms.
• Recirculate rather than draw in. If there is any ventilation system or air conditioning, set it to recirculate or turn it off, exactly as the card says.
• Trickle vents closed, and the extractor fans off, since they pull outside air in through every gap.
• Do not vacuum, which lifts settled particles back into the air.
• Do not burn anything indoors, including candles, a stove or a hob, while sealed in.
• One room, with the people and the fan in it, rather than trying to treat the house.

Open up once the air outside is clear, and then ventilate properly, because indoor air in a sealed room goes stale quickly and carbon dioxide builds.

If you are the one who could start it

Worth saying, because the majority of British wildfires are started by people, and the households reading this app are exactly the ones lighting fires outdoors.

• No fires, stoves or barbecues on grass, heath, moor or in woodland during a dry spell. Not a small one, not a contained one.
• Never on peat, ever, per the Dakota fire hole page.
• Disposable barbecues are the classic ignition source. They stay hot for hours and they scorch through to what is underneath.
• Glass and mirrors left in dry vegetation focus sunlight.
• Drown a fire, stir it, and feel it with the back of your hand before leaving. Warm means not out.
• Ring 999 for any fire in the open that is not yours and under control. Early is what keeps a grass fire small.