Dr. Thomas C. (Tom) O'Connor received his foundation in atmospheric aerosols through his M. Sc. work at University College Dublin (with P.J. Nolan) and then as research scholar with Leo W. Pollak at the Dublin Institute of Advanced Studies. On moving to Galway in 1956, a significant legacy was his choosing of a field station site at Mace Head and his pioneering measurements there. He played a pivotal role in the development and progression of the Mace Head Atmospheric Research Station (www.macehead.org) for some 50 years. He passed away peacefully in November 2012.