Ryan was a Research Associate and member of the Air Pollution team at SEI York.

He worked on research projects funded by the Climate and Clean Air Coalition (CCAC), the UK Global Challenges Research Fund (GCRF), the German Organization for International Development (GIZ) and other initiatives developed by SEI.

Ryan assisted national and local governments in Korea, Morocco and Cambodia planning strategies to achieve development benefits by reducing impacts on human health, crop yields and contributing to the global drive to combat climate change.