Details of Swansea Plume Plotter

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

Stacks and buildings

Building measurements are taken from the building plans. 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.

Stack measurements

All of these are taken from [1]:

Stack location: 51.664517,-3.9061679.
Stack height: 25 m.
Stack diameter: 0.85 m.
Stack gas exit velocity: 16.07 m/s.
Stack gas temperature: 190 °C.

The following values are used for albedo, Bowen ratio, and roughness length. None of these are specified in [1]:

Albedo: 0.2.
Bowen ratio: 1.
Roughness length: 0.2. (AERMOD's "urban" option was used, with roughness 1.0 m.)

Emissions

The emission rates of pollutants are taken from [1]:

Pollutant	Emission rate per second
Oxides of nitrogen	1.387 g
Particulates	69 mg
Sulphur dioxide	347 mg
Carbon monoxide	347 mg
Hydrogen chloride	69 mg
Hydrogen fluoride	6.93 mg
VOCs	69 mg
Cadmium and thallium	350 μg
Mercury	350 μg
Other metals	3.47 mg
Dioxins and furans	693.3 pg
PAHs	119.5 ng
PCBs	63.79 pg

Background levels

The background levels of pollutants are taken from [1]:

Pollutant	Background concentration per m³
Oxides of nitrogen	12.64 μg
Particulates	12.73 μg
Sulphur dioxide	3.33 μg
Carbon monoxide	112 μg
Hydrogen chloride	212 ng
Hydrogen fluoride	N/A
VOCs	450 ng
Cadmium and thallium	320 pg
Mercury	3.5 ng
Other metals	70.98 ng
Dioxins and furans	N/A
PAHs	400 pg
PCBs	N/A

Weather data

Weather data is taken from METAR reports from a local airport: Cardiff.

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

References

1. Proposed Small Scale Energy Recovery Facility On Land at Swansea Depot, Clarion Close, Morriston, Swansea -- Air Quality Assessment. WYG. December 2018.