Some very serious concerns have been raised about air quality in underground heavy rail systems.
These studies are not opinions teams of international experts studied this in great detail.
www.popsci.com/story/health/subway-public-transit-cities-pollution-health/
Gretchen Goldman
Assistant Director for Environmental Science,
Engineering, Policy, and Justice at White House Office of Science and Technology Policy,
carried out the study on Air pollution in the underground subways in the USA.
https://ehp.niehs.nih.gov/doi/10.1289/EHP7202
This one on Air Quality on the London Underground
www.sciencedirect.com/science/article/abs/pii/S2212095519301488?dgcid=coauthor
www.who.int/news/item/22-09-2021-new-who-global-air-quality-guidelines-aim-to-save-millions-of-lives-from-air-pollution
www.sciencedirect.com/science/article/abs/pii/S0360132321003139
There are a large number of people in Ireland who suffer from respiratory distress and disease.
www.medicalindependent.ie/documenting-the-respiratory-health-of-the-nation/#:~:text=Deaths%3A%20Respiratory%20diseases%20cause%20almost,with%205%2C720%20deaths%20in%202016.
www.statista.com/statistics/660231/disease-of-the-respiratory-system-deaths-ireland/
These are just a few of the concerns about the use of heavy rail above and below ground but these are the most important for the health and well-being of our citizens and visitors to Ireland.