Local Air Quality Management: Emissions Inventory

New Emissions Inventory for Climate Change.

The Sussex Air Quality Steering Group is commited to updating and building on the existing emissions inventory for Sussex. It is envisaged that an updated version of the inventory will be compiled through 2005. As well as updating the inventory for pollutants such as NOx, SO2, PM and O3, the group are widening the inventory to encompass greenhouse gases relative to Climate Change and Sustainability indices. These will include CO2 and possibly CFC's. There will be a wider focus on emissions to include; domestic, transport (road, sea & air), industry, agriculture and natural habitats.

Original Emissions Inventory.

One of the tools used in the assessment of air quality is the emissions inventory. An emissions inventory is a geographically referenced list of pollution sources which estimate the type and quantity of pollutants emitted to the air. The emissions estimates are based on emission factors, e.g., a known amount of NO₂ is emitted from a given type of vehicle exhaust at a given speed, per kilometre travelled. An Emissions inventory is therefore composed of databases of activity data over the relevant time period (e.g. daily vehicle flows along a stretch of road), and emission factors for these activities (e.g. vehicle emission factors derived from engine testing).

The Sussex Air Quality Steering Group commissioned environmental consultants CES to construct an atmospheric emissions inventory covering East and West Sussex. The final product was the first UK use of CES UKRAPID system. Rather than a static snapshot of emissions in the County, the group wanted a document which could be easily updated, to allow assessments of changing emission levels through time.

The Sussex Inventory contains information on the following sources: Industrial sources including the 4 currently active Part A processes (large industries such as chemical works and power stations regulated by the Environment Agency), over 200 Part B Processes (smaller industrial processes such as vehicle resprayers and timber works, regulated by local authorities), Road traffic, Domestic premises, Commercial premises and ports (Newhaven, Shoreham and Gatwick).

The contribution of the different emission sectors to emissions in Sussex is shown in the chart below:

This chart shows the dominance of road transport as a source of many air pollutants in Sussex.

It is also possible using a Geographical Information System to map the location of sources of air pollution. The map below shows 1km grid square total emissions of nitrogen oxides form the emissions inventory.

Again, the importance of road transport as a source of emissions can be seen for this pollutant, as well as the prominence of emission sources in town centres (due to slower moving traffic and domestic and commercial energy use).

The Group is working on updating its emission inventory, and these pages will be updated accordingly.