In 2015 over 1 billion people (14.3% of the world’s population) lived within 100 km of a volcano that has erupted during the Holocene. However, those living further away are not immune from volcanic effects. For example, the 2010 eruption of Iceland's Eyjafjallajökull volcano had a huge impact on air travel, with over 300 airports in approximately 25 countries, and a correspondingly large airspace, closed in Europe during 15-21 April 2010. Over 100,000 flights were cancelled over that week, affecting 7 million passengers, and resulting in $1.7 billion USD in lost revenue to airlines. This joint Institute of Physics ‘Environmental Physics Group’ Day and Royal Meteorological Society event will bring together experts in the impacts of volcanic eruptions; including local air quality, atmospheric composition, aviation and climate change. Through a series of talks the day will provide valuable insights and observations regarding the impact of volcanic eruptions on the environment. The day will start with an overview of volcanic processes and effects before three focussed sessions on: Local Volcanic Effects; Volcanic Changes to Atmospheric Composition and Climate; and Volcanic Effects on Aviation. The day will end with a look at the future of volcanic monitoring and hazard warning.