Details of Gloucestershire Plume Plotter

This page should be read in conjunction with How Plume Plotter Works. It provides more details specific to the Gloucestershire version of Plume Plotter.

Stacks and buildings

Building measurements are taken from [3]. This image shows the layout of the stack and buildings modelled. North is at the top; colours and numbers indicate the height of the buildings and the stack. Note that the strange sloping roof is represented by a stepped sequence of buildings (actually tiers); this represents the slope more accurately than a single flat-roofed building.

Stack measurements

All of these are taken from [1] [2]:

Emissions

The emission rates of pollutants are of two types. Both are calculated using the flow rate reported in [1] [2], which is multiplied by the emission concentrations.

For the planned emission rates, the concentrations used are the IED limits, as stated in (e.g.) [1] [2]. Resulting (mass per second) emission rates are listed below:

PollutantEmission rate
per second
Oxides of nitrogen6.991 g
Sulphur dioxide1.748 g
Carbon monoxide1.748 g
Particulates350 mg
Hydrogen chloride350 mg
Hydrogen flouride35 mg
VOCs350 mg
Ammonia350 mg
Mercury2 mg
Cadmium and thallium2 mg
Other metals17 mg
Dioxins and furans3.495 ng
Benzo(a)pyrene6.991 μg

The actual emission rates use the same flow rates and the annual average concentrations for 2020, as reported in the incinerator's annual report. They are listed below:

PollutantEmission rate
per second
Oxides of nitrogen5.033 g
Sulphur dioxide337 mg
Carbon monoxide1 mg
Particulates4.89 mg
Hydrogen chloride197.1 mg
Hydrogen flouride2.62 mg
VOCs24.8 mg
Ammonia46.8 mg
Mercury62 μg
Cadmium and thallium17.13 μg
Other metals591 μg
Dioxins and furans241.6 pg
Benzo(a)pyrene373 ng

Background levels

PollutantBackground
concentration per m3
Oxides of nitrogen15.3 μg
Sulphur dioxide2.6 μg
Carbon monoxide324 μg
Particulates15.4 μg
Hydrogen chloride2.35 μg
Hydrogen flouride560 ng
VOCs500 ng
Ammonia2.6 μg
Mercury30 pg
Cadmium and thallium430 pg
Other metals20.75 ng
Dioxins and furans44.1 fg
Benzo(a)pyrene210 pg

Background levels of pollutants are taken from the following sources

Nitrogen dioxide, Particulates PM10, Particulates PM2.5: Latest average value for Gloucester City area from DEFRA.

Sulphur dioxide, Carbon monoxide: 2001 average value for Gloucester City area from DEFRA.

VOCs: 2010 (benzene), 2003 (1,3-butadiene) average value for Gloucester City area from DEFRA.

Ammonia: Gaseous ammonia at Rosemaund, 2014 from DEFRA.

Hydrogen chloride, Hydrogen flouride: Assumed by [1].

Mercury, Cadmium and thallium, Other metals, Dioxins and furans, Benzo(a)pyrene: From site survey [1].

Weather data

Most weather data (wind speed and direction, and temperature) is taken from a private weather station in Quedgeley. Other data is taken from Bristol airport, which is the closest 24-hour airport.

Upper air data is the latest reported by the Nottingham upper air station.

References

1. URBASER GLOUCESTERSHIRE AIR QUALITY ASSESSMENT, Fichtner, 2012.

2. URBASER JAVELIN PARK ENERGY RECOVERY FACILITY AIR QUALITY ANALYSIS, Fichtner, October 2017.

3. Building plans, September 2011.