This page should be read in conjunction with How Plume Plotter Works. It provides more details specific to the Gloucestershire version of Plume Plotter.
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.
All of these are taken from [1] [2]:
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:
| Pollutant | Emission rate per second |
|---|---|
| Oxides of nitrogen | 6.991 g |
| Sulphur dioxide | 1.748 g |
| Carbon monoxide | 1.748 g |
| Particulates | 350 mg |
| Hydrogen chloride | 350 mg |
| Hydrogen flouride | 35 mg |
| VOCs | 350 mg |
| Ammonia | 350 mg |
| Mercury | 2 mg |
| Cadmium and thallium | 2 mg |
| Other metals | 17 mg |
| Dioxins and furans | 3.495 ng |
| Benzo(a)pyrene | 6.991 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:
| Pollutant | Emission rate per second |
|---|---|
| Oxides of nitrogen | 5.033 g |
| Sulphur dioxide | 337 mg |
| Carbon monoxide | 1 mg |
| Particulates | 4.89 mg |
| Hydrogen chloride | 197.1 mg |
| Hydrogen flouride | 2.62 mg |
| VOCs | 24.8 mg |
| Ammonia | 46.8 mg |
| Mercury | 62 μg |
| Cadmium and thallium | 17.13 μg |
| Other metals | 591 μg |
| Dioxins and furans | 241.6 pg |
| Benzo(a)pyrene | 373 ng |
| Pollutant | Background concentration per m3 |
|---|---|
| Oxides of nitrogen | 15.3 μg |
| Sulphur dioxide | 2.6 μg |
| Carbon monoxide | 324 μg |
| Particulates | 15.4 μg |
| Hydrogen chloride | 2.35 μg |
| Hydrogen flouride | 560 ng |
| VOCs | 500 ng |
| Ammonia | 2.6 μg |
| Mercury | 30 pg |
| Cadmium and thallium | 430 pg |
| Other metals | 20.75 ng |
| Dioxins and furans | 44.1 fg |
| Benzo(a)pyrene | 210 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].
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.
1. URBASER GLOUCESTERSHIRE AIR QUALITY ASSESSMENT, Fichtner, 2012.
2. URBASER JAVELIN PARK ENERGY RECOVERY FACILITY AIR QUALITY ANALYSIS, Fichtner, October 2017.