| Topic: | Re:Re:Re:Re:Re:Re:Re:Re:How Many Trees Will Go from the High Road for CS9 and where? | |
| Posted by: | Tom Pike | |
| Date/Time: | 26/10/17 11:44:00 |
| Kevin, of course the 2% figure for CO2 is an estimate based on sequestration - it's an overall offset of the CO2 emitted by the traffic, not an estimate of any change in the CO2 itself along the High Road. As for particulate absorption by trees, there's been quite a bit of work done on this, and the 2% figure comes from a highly cited study* that looked specifically at London. It gave a figure of 0.7 to 1.4% and I've rounded up to 2%. Even with a 50% increase in tree cover, the reduction only reaches 2.6%. You claim that the pollution monitoring data can't tell us anything about the effect of previous cycleways, but again provide no evidence to back up your claim. As you have looked in detail at the data, to demonstrate your point you might have shown that the variability of the annual measurements over the years before opening was much larger than any change seen after they opened. If that were indeed the case I could agree with you. We can test your claim with the data. I have given the actual numbers, in terms of the previous variability of pollution before the segregated cycleways were being built and the change after they opened. Here they are again, with the change and previous variability in brackets. PM10 - Upper Thames Street: -17% (3%) NO - Walbrook Wharf: 0% (8%) Mile End: +8% (12%), NO2 - Walbrook Wharf: -19% (6%), Mile End: -13% (6%) NOx - Walbrook Wharf: -5% (6%) For PM10's, NO2 and overall NOX the changes are all significantly down, and much larger than the variability, with the opening of the cycleways. In these cases you should be able to agree that there is a significant reduction in these pollutants. For NO the changes are less than the variability, and in that case we would agree that there is no significant change. This is not difficult to calculate, so if you see an obvious problem with these numbers, please point it out. I'm afraid a claim, without any evidence, that that the situation is too complex to say anything, is just that, an empty claim. *Estimating the removal of atmospheric particulate pollution by the urban tree canopy of London, under current and future environments, Landscape and Urban Planning, Vol. 103, No. 2, 30.11.2011, p. 129-138 |