This study aims to test if it is feasible to introduce lung cancer screening in Ireland. People within a certain age group, who smoke or who smoked in the past, are at a greater risk of developing lung cancer. They can also develop chronic lung conditions that can affect their long-term health. In Ireland, about 2,690 people are diagnosed with Lung Cancer every year. Unfortunately, 2 out of every 3 people diagnosed with lung cancer die per year. The goal of this study is to try to screen for lung cancer in people before they have symptoms associated with the disease. We aim to do this by selecting people based on their age, whether they have smoked in the past or currently smoke as well as other relevant factors. People who take part in this study will have an assessment of how their lungs work and a low-dose CT scan. This is called a lung health check. The goal of the low-dose CT scan is to pick up lung cancer before it becomes symptomatic, and at an earlier stage. This scan uses a very low dose of radiation. Unfortunately, without early detection, such as is the goal of this trial, 8 out of 10 people who go on to develop lung cancer will have advanced lung cancer when it is discovered, where outcomes tend to be poor. The earlier detection of lung cancer has a greater potential for treatment. Current international recommendations suggest carrying out these scans in the community rather than in a hospital. Therefore, we aim to deliver these lung health checks using a mobile unit in the community. This study aims to test if we will successfully pick up lung cancer earlier by doing community-based 'lung health check's using mobile units in North Dublin and the North East, among people of a certain age and smoking history.