Hi Tom

I’m guessing this is a POCP issue? If so, it’s actually due to “controlled burning of managed forests” I believe, so even non-engineered timber should still incur this impact (or there’s something wrong with our background data).

There’re a few issues here:
– POCP (Smog) was a big issue in built up areas in Europe but vehicle and industrial emissions laws quickly resolved this to a large extent.
– It’s still a big issue in China and India but I think that is probably largely due to two stroke motorbike engines as much as industry (at this stage).
– Nevertheless, it’s definitely not a major issue in Australia. The biggest air quality issues our society have had recently were caused by severe bushfires > fuelled by climate change.
– The POCP release in this case (managed forests) is not in built up areas, so the health / nuisance impact is relatively low compared to an industrial plant, or vehicles in a city.
– Unfortunately there are no “fate models” for POCP that accurately model this important aspect of geography and population density. It really is a very localised impact but in this case is being treated as a global impact which I don’t think is quite right.

So relying on the POCP indicator in this study to make decisions, that is, considering pumping more CO2 into the atmosphere (concrete and steel production) to reduce smog due to controlled burning of forestry assets wouldn’t be wise. POCP just isn’t a big issue so shouldn’t be given large priority.

I think this is generally the case when looking at the other indicators, there needs to be a significant increase before the benefits of GWP reductions need to be questioned.