| Topic: | Re:Re:Re:Re:Air pollution in Putney | |
| Posted by: | Richard Hodges | |
| Date/Time: | 20/02/14 15:21:00 |
| "Aircraft are largely irrelevant to air pollution in Putney, hence the pressing need to focus on local sources" Then feel free to explain the clear pattern in the NO2 metering that's independent of the traffic pattern, and runs very clearly from 6.00am to 11:00pm. Why is this pattern so clear on some days, but totally absent on others? Or let's try from a different angle. How much NO2 does a Trent engine produce on normal throttle openings for landing approach? Put that in a form most people can understand - an equivalent number of cars, or number of buses. At peak, multi-engined planes are flying over every 30 seconds at 2-3,000 feet, which isn't that large a distance (many of us live further from the High Street than that). Low level flight only takes place over a portion of the city - its effect is as geographically variable as that from roads and other major sources. Trying to hide it in wider figures is disingenuous: 7.5% over all of London becomes 14% of half of London, or 25% over a quarter. The 6-11 pattern amounts to about 25% of the total on average, although this is very variable - higher and lower. Care to explain that? |