“How dark is your sky?” Estimating artificial light in Ireland from satellite imagery, 2015-2019

Nationally, we see that county Dublin has the highest levels of artificial light emissions in January 2019 (11.53) and Leitrim has the lowest (0.52). Indeed, Dublin emissions are almost 7 times higher than Louth, the next highest county (1.70) in January 2019. 

The counties with the next highest emissions are Kildare (1.49 units), Meath (1.15 units), Limerick (1.03 units), Cork (0.91 units), Waterford (0.90 units) and Westmeath (0.85 units). 

It can be seen from Fig 3.1 that high emissions counties tend to cluster in the East and the South of Ireland, due to the presence of major urban settlements. 

The counties with the lowest emissions in 2019 were, in addition to Leitrim, Mayo (0.55 units), Kerry (0.58 units), Roscommon (0.64 units) and Sligo (0.65 units). Counties with the lowest emissions levels tend to be found on the Western Seaboard.

Midland counties fall in the middle of county distribution, with average emissions ranging from 0.68 in Offaly to 0.85 in Westmeath. The South-East tends to have slightly higher average emissions ranging from 0.73 in Kilkenny to 0.9 in Waterford.