26 Air Monitoring


London Pilot Project Kick Starts a New Greenhouse Gas Emissions Measurement Service


The National Physical Laboratory’s (NPL) Melanie Williams presents the results of a 2012 pilot study and outlines how it will form the basis of a new emissions measuring offer from Astrium.


The National Physical Laboratory (NPL) is partnering with Astrium Services to deliver a new emissions measurement service to enable countries and cities to better quantify their greenhouse gas (GHG) emissions.


It is essential that we are able to assess and control GHG emissions at international, national and major city level, to both reduce the level of polluting emissions and to promote the uptake of new low carbon technologies.


The new offer takes the learning from a pilot in London and uses it to complement the current ‘inventory approach’ models and validate national and international energy saving measures.


What makes the new service different is that it will use actual measurements of carbon dioxide and methane in the atmosphere, together with a bespoke atmospheric model, to provide a much greater level of accuracy than is available at present.


This article takes a preliminary look at the measurements which came from the successful pilot study in 2012 and outlines how these results will be taken forward to form the basis of the new service.


Establishing the Need


There is a global commitment to lowering GHG emissions. Countries have their independent plans to decarbonise their energy, transport and other industrial sectors and we are all encouraged to save energy in all that we do. In Europe and the UK measures have been made to incentivise the move to a low carbon economy and as other countries are added to this list, and put in place measures like biomass, nuclear energy, carbon capture and storage, they will want to see real local reductions in GHG concentrations in the atmosphere. This will see cities as well as nations looking at the GHG emissions and how they can provide evidence of lowering emissions.


Enhancing the Current Approach


Current emissions, whether national or local are calculated using the ‘inventory approach’. This multiplies data –such as the number of miles driven by an average person– by ‘emissions factors’ to turn that activity data into the equivalent tonnes of carbon dioxide.


Astrium’s new Emissions Measurement Service will complement and improve this approach by using actual concentration measurements. We are confi dent it will achieve this as parallels with ‘traditional pollutants’, such as acid gases, show that inventories often underestimates emissions.


Melanie Williams,


National Physical Laboratory Hampton Road, Teddington, Middlesex, TW11 0LW, UK Tel: 0041 788227219


Email: melanie.williams2@npl.co.uk Web: www.npl.co.uk


IET March / April 2014 www.envirotech-online.com


The new service will take measurements from a range of sources. This will include permanent elevated sites round the country, as well as aircraft and eventually satellite measurements of carbon dioxide too. These will then be fed into the sophisticated model, and combined with inventories of natural and manmade GHG sources and sinks. By merging actual measurements with traditional modelling we will enable better validation of energy saving and decarbonising measures and be able to say with confi dence if they are having the intended effect of reducing actual GHG emissions.


Data quality is essential when looking for small changes over a number of years so NPL will produce the highest-quality calibration gas standards to underpin the quality of the data used in the service.


The Initial Pilot


Over three months of the summer of 2012, Astrium and its partners NPL, Le Laboratoire des Sciences du Climat et l’Environnement (LSCE) and the National Centre for Earth Observation ran a pilot study in London to measure carbon dioxide, methane and carbon monoxide concentrations at four sites in or near the city. The objective was to predict and solve any practical issues before the launch of the full service in 2013 as well as answer some interesting scientifi c questions including:


1.How do concentrations of carbon dioxide and methane vary between rural, Outer London and London Centre sites?


2.How do meteorological conditions impact on these measured concentrations?


3.How do expected concentrations from known sources compare with the measured concentrations for this period?


Gases Measured by the London Pilot Study


Carbon Dioxide: in terms of tonnes emitted annually this is the most important GHG. It comes from burning fossil fuel in power generation, road and air transport and natural sources.


Methane: is emitted from waste management, agriculture, gas distribution, mining, aviation and road traffi c. Also produced by natural sources. Methane is more potent than carbon dioxide as a GHG by a factor of twenty fi ve.


Carbon Monoxide: is almost exclusively produced by incomplete combustion of fossil fuels and will be used in the Emissions Measurement Service as a marker for manmade sources of GHG emissions.


Four state-of-the-art GHG sensors were installed at sites in and around London. One was sited to the west of London in the suburbs at Teddington. The second was at Poplar and the third was at a site in Hackney. The fi nal sensor was placed in Detling, in the countryside to the east of London (see map below).


The sites were chosen to be on an approximate west -east transept across London, using existing air quality measurement infrastructure and every site was elevated at 10 m above ground level to ensure the measurements were not too dominated by local sources. The predominant wind direction is from the west.


The measurements needed to be made to the highest accuracy so the sensors were calibrated throughout the measurement campaign with synthetic gas standards, produced gravimetrically to have the same isotopic composition as that of naturally occurring carbon dioxide in the atmosphere.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76