Portlaoise is the brightest place in Laois for the wrong reasons

People living in the Portlaoise area are exposed to the highest levels of artificial light pollution in Laois while people living in the west of Laois have one of the lowest levels in Ireland according to a new survey.

The Central Statistics Office has published a new survey called 'How dark is your sky? Estimating artificial light in Ireland from satellite imagery'.

It reveals light levels nationally, by county and by local electoral area.

The Portlaoise LEA ranks in the top half of the table with Ashbourne in Co Meath. The most populated area of Laois ranks above Tullamore in Offaly and Carlow town.

The total population of the Portlaoise local electoral area is 31,794 people with more than 20,000 living in the county town environs. It stretches to the Kilkenny border taking in Abbeyleix, Ballinakill and Ballyroan.

The other two Laois LEAs are in the bottom half. The Graigue Portarlington district has the same level as the Kilkenny city East Kilkenny district.

The population of this area is 28,096. It also includes Stradbally, Timahoe, Ballylinan, Ballyadams, Killeshin, Crettyard, Killenard, Ballybrittas. It borders Kildare, Carlow, Kilkenny and Offaly.

The Borris-in-Ossory Mountmellick LEA is in the bottom 20 districts in Ireland for artificial light levels. The district is less populated, with 24,807 but is the biggest geographically in Laois. It includes Rathdowney, Mountrath, Durrow, Castletown, Camross, Errill, Clonaslee and Rosenallis. It borders Tipperary, Kilkenny and Offaly.

Dublin’s Pembroke South Dock and the North Inner City have high light emissions. South and West Kerry and West Mayo have very low light emissions.

Nationally Laois ranks in the middle of the county table in terms of light pollution but the county has more artificial light than Kilkenny, Tipperary or Offaly.

Dublin has the highest levels of artificial light emissions in January 2019 (11.53) and Leitrim has the lowest (0.52).

The survey also found that Ireland has lower artificial light emissions than other European countries such as the UK, Portugal and the Netherlands.

It said Irish cities have lower light emissions than international counterparts such as London and Paris.

This analysis was carried out by the CSO with Graphical Information Systems (GIS) software tools combining Ordnance Survey mapping information with satellite data on monthly cloud-free light emissions from the Visible Infrared Imaging Radiometer Suite Day Night Band (VIIRS-DNB) sensor on the Suomi-NPP satellite, operated by the NOAA.