SCAIL - Combustion 
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NOTICES

September 9th 2025: SCAIL background pollution maps for Ireland have been updated to the the year 2021 in line with current APIS (see announcement).

Notice Archive

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Simple Calculation of Atmospheric Impact Limits from Combustion Sources (SCAIL-Combustion) is a screening tool for assessing the impact from combustion plant on semi-natural areas like SSSIs and SACs. The model provides an estimate of the amount of acidity, nitrogen and sulphur deposited on a habitat from the combustion source. This value can then be used to assess whether impact limits for the habitats are exceeded or not.

info Allows the user to reload previously saved input files. [close]
Project Details
Project Notes  
info Use the Project Notes box to enter extra information about the project, source or receptor. For example, add a project name and run details, SSSI site name, habitat structure, or topography etc.[close]
Project Run Mode  
info The project run mode allows the user to specify whether to use 1. \"Hybrid mode\" which calculates concentrations either side of the receptor location for x4 10 degree sectors (see User Guide for details) or 2. In \"Conservative mode\" the habitat site is rotated so that it is in the prevailing wind direction for the meteorological file being used. 3. The \"Realistic mode\" calculates the actual position of the habitat site and should only be used for interest and not as the only run mode for an application. The \"Conservative & Hybrid modes\" can help to ensure that the effects of local wind fields are captured, however the method works best for situations where there are either single stacks or stacks are closely grouped and care needs to be taken when dealing with stacks that are widely spaced apart. \n\nIf in doubt run the model for both \"Conservative mode\" and \"Hybrid mode\" and use the higher of the results. Where SCAIL-Combustion is to be used for regulatory screening purposes, results produced using either the \"Hybrid mode\" or \"Conservative mode\" must be reported. Please consult the user guide and technical report for further information including the use of SCAIL for modelling multiple installations or dispersed sources. [close]
 Hybrid Mode  Conservative Mode  Realistic Mode
Location Details
Select Country  
info Select the Country where the habitat is located. [close]
Installation Details
Installation  
info Use INSTALLATIONS to group your sources, the first installation is used as the datum point for the Habitat Lookup and for Conservative & Hybrid modes so makes sure that this reflects the location of most significant emissions. Please note that all sources within an installation will be summed in the output page so if you want to know the specific contribution from a single source (or a group of sources) you should run them as separate installations. The use of SCAIL-Combustion is not suitable for regulatory screening of sites with multiple installations or dispersed sources, and the relevant Regulatory Authority should be contacted for advice. [close]
Installation Name  
info Provide a name or description of your Installation or group of sources. [close]
Installation Location  
info Provide the location of your Installation in National Grid or Land Ranger (Great Britain only) format. [close]
Landranger x,y
 
info Provides a link to GoogleMaps to check the location. [close]
Stack details:
Stack
info More than one source may be added by selecting 'Add Source', Sources can be removed from the analysis using the delete button. [close]
Delete
Stack Name
info Provide identification for stack. If site has only a few stacks they can be added as separate stacks with individual names. [close]
New or Existing
info If your application is for a new installation or source, select 'New'. If you are including an existing source and it was operational before 2004, select 'Existing'. [close]
Stack Height
info Add the height of each stack in metres. [close]
metres
Stack inner diameter
info Add the diameter of each stack in metres. [close]
metres
Stack Gas Temperature
info Add the gas temperature for each stack in degrees Celsius. [close]
°C
Stack Gas Velocity
info Enter gas exit velocity in m/s. [close]
m/s
NOx Emission rate
info Enter emission rate in g/s, kg/day or tonnes per year. If the emission rate is not known it can be calculated from concentration and volume flux data using the Emission Calculator button. [close]
SO2 Emission rate
info Enter emission rate in g/s, kg/day or tonnes per year. If the emission rate is not known it can be calculated from concentration and volume flux data using the Emission Calculator button. [close]
PM10 Emission rate
info Enter emission rate in g/s, kg/day or tonnes per year. If the emission rate is not known it can be calculated from concentration and volume flux data using the Emission Calculator button. [close]
info If you have data from a report on stack monitoring, providing information on the concentrations of NO2 or SO2 in the exhaust air from the stack and the associated volumetric flow rate, then you can use the emission calculator to determine the emission rate (in grams per second) to be entered into SCAIL-Combustion. You should ensure that both the air concentration and the volumetric flow rate are presented as normalised values, defined in the appropriate sector guidance notes. [close]
Operating hours
info Put in the number operating hours over the year for your installation. [close]
hours
Stack Grid Reference
info Put in the grid reference of the location of the stack. You can enter either Landranger (e.g. NJ692258) ore OS x,y co-ordinates (e.g. 369250,825850) in metres. For Northern Ireland only x,y co-ordinates (e.g. 145665,156755) in metres can be used. [close]
Landranger x,y
info Provides a link to GoogleMaps to check the stack location.[close]
Plant Capacity
info Aggregated plant capacity in megawatts, this option will provide a default radius search for the site details but can be changed. Non-sulphurous fuel: Natural gas and gas oil, including ultra-low sulphur diesel and low sulphur diesel. Sulphurous fuel: Low - Gas other than natural gas, including biogas and landfill gas; High - solid and liquid heavy fuel oil, including combustion appliances and incinerators. [close]
Megawatt Sulphurous non-Sulphurous
Designated Site details:
Search Radius 
info Enter the radius that you wish to search for habiats sites around your installation. Please note that this search is centred on installation number 1. [close]
 km  
info Use this button to query the database of habitats included in SCAIL-Agriculture. Please note that RAMSAR sites are not included and should be added manually. [close]
No. of Designated Sites 
info This displays the number of habitat sites that were found within the specified radius of installation number 1. The value cannot be edited. [close]
0 found
  
info Use this button to view receptors (shown in blue) and the location of Installation No. 1 (shown in red) in GoogleMaps. If receptors do not display then click on Run Receptor Search to re-run the query of the database. [close]
User specified site Delete
Site Name
Site Location
Landranger x,y
 
info Provides a link to GoogleMaps to check the location. [close]
Habitat within site  
info Use this button to query the database of background ammonia concentrations, nitrogen deposition and acid deposition that are used in the assessment. [close]
 
Human Health Receptor Details
Receptor Delete PM10 percentile   
info Select the statistic for evaluating PM10 concentrations, this can be the Annual, 24 hour mean or 90.41th Percentile (not to be exceeded more than 35 times a year) or 98th Percentile in Scotland (not to be exceeded more than 7 times a year). [close]

NO2 percentile    
info Select the statistic for evaluating NOx concentrations, this can be the Annual or 1 hour mean or 99.79th Percentile (not to be exceeded more than 18 times a year) [close]

SO2 percentile    
info Select the statistic for evaluating SO2 concentrations, this can be the 15 minute mean or 99.9th Percentile (not to be exceeded more than 35 times a year), 1 hour mean or 99.73th Percentile (not to be exceeded more than 24 times a year) or 24 hour mean or 99th Percentile (not to be exceeded more than 3 times a year) [close]
Receptor Name
Receptor Location
Landranger x,y
 
info Provides a link to GoogleMaps to check the location. [close]
 
info Use this button to query the database of background PM10 concentrations that are used in the assessment. [close]