Sherman Road smog debacle
Last Wednesday evening I took my two sons and their friend up to Sherman Road soccer fields to kick a ball around. It was a beautiful evening, with the sunset breaking through the clouds after days of heavy rain. Unfortunately, our experience, and that of the 80 or so other youth soccer players present was heavily clouded by the folly of a nearby neighbour who lit a backyard slash pile that proceeded to smoulder and spread a dense smog of particulate matter across the playing fields for over 2 hours. As one of my children suffers from bouts of asthma, i found this of grave concern.
No less damaging was how the smouldering mess fueled faulty assumptions about the inherent ‘dirtiness’ of wood-fire. Smoke only escapes a fire and enters the atmosphere (to become a pollutant) when it has not reached a hot enough temperature to ignite. Gas/smoke/fuel is released from the wood at around 150c, but ignition only occurs above 300c. Complete combustion of all volatiles only occurs above 600c, and the hotter the better.
Masonry heaters and rocket mass heaters routinely achieve temperatures well over 600c because they are designed to ‘burn hot and store the heat’. Modern metal box stoves with well-maintained reburn chambers can also achieve a clean burn so long as they are operated properly. But to make an outdoor fire burn relatively clean one has to build up a tall narrow core so that the smoke from the perimeter is drawn into the central flame path and upwards. This requires almost constant attention, and is virtually impossible when adding damp material – which our soccer field neighbour was no doubt attempting to do.
I know there has been a strong call in recent years to ban wood-fire altogether, and with all the malpractice at play I can’t blame people. That said, if we are really going to get off the fossil fuel sauce in time to avert major environmental/social/economic catastrophe, then we had best wake up from our ‘flick of a switch’ energy ignorance, and (re)discover how to burn bio-mass in a clean and efficient manner. The answers are clearly available, we just have to seek beyond the smog of faulty assumptions and multi-generational bad burning habits.