Some good news from the pandemic

June 16, 2020 10:21 PM
By Peter Dobbs

As expected, NOx pollution is down. How can we make it last?

Graph of NOx figures 2018-20 (Peter Dobbs)The latest data from Derbyshire Dales District Council shows a dramatic drop in levels of the atmospheric pollutant nitrogen dioxide (NOx), recorded at various points around Ashbourne.

Sample tubes have been sited at 7 points around Ashbourne up from 3 since last summer when local Lib Dems helped put pressure on the council to increase testing.

In general the values have halved. Most of this reduction can probably be attributed to the reduction in cars and lorries. However the reduction in traffic was overall significantly more than 50%, so the level of 'residual pollution' needs some additional detective work to understand what is happening.

Government figures for average 'rural background' indicates a NOx level around 7ugm-3. Anything above this is due to human activity largely associated with homes and transport.

The halving of NOx levels is broadly similar to that reported from large cities around the UK. Road traffic also decreased dramatically but whereas van and car traffic fell to about 20 -30% of normal, HGV traffic (distributing goods regarded as essential) fell only to about 60%. Due to their size and engine type these vehicles produce a disproportionate amount of NOx per vehicle.

NOx data 2019-2020 opp 25 Buxton Rd (Peter Dobbs)

Data from further up the hill

It is worth noting that even with HGV numbers reduced, the air quality at one point on Buxton Road still barely qualified as acceptable under current legislation.

More worrying, if the data from the pandemic is omitted both trend lines (straight lines on the graphs) are NOT decreasing - pollution seems to have been getting worse on Buxton Road.

This suggests that an overall reduction in road traffic of at least 30% on the A515 northbound out of Ashbourne, or alternatively a major reduction in HGV numbers in particular, will be required to keep the air fit to breathe for some Ashbourne residents.

DDDC promised in the Full Council meeting on 5th March to publish an Air Quality Monitoring Report by July this year. Due to there now being over two years of data showing consistently high values of NOx on Buxton Road, legislation indicates that the District Council should also declare an Air Quality Management Area on Buxton Road. It will then have about a year, working with other interested parties (presumably Derbyshire County Council and the Traffic Group from Ashbourne Town Team) to devise an appropriate Action Plan to address the problem.