The interest in hydrogen as an alternative to fossil fuels is rapidly increasing worldwide, leading to a strong push for transitioning towards a hydrogen-based economy. However, the environmental implications of this shift are not yet fully understood. To address this gap, the Atmospheric Chemistry Special Interest Group is organizing a two-day event in Cambridge dedicated to exploring hydrogen's chemistry and its effects on atmospheric composition and climate. The event will conclude the UK Hydrogen Environmental Impacts Programme, which is backed by NERC and the Department of Energy Security and Net Zero. The first day of the event will delve into various aspects of the environmental impacts of hydrogen energy, including discussions on global and UK hydrogen use scenarios, fugitive hydrogen emissions, and atmospheric hydrogen uptake by soils. The second day, led by the programme, will further explore related topics to deepen the understanding of hydrogen's environmental effects. Participants have the flexibility to register for either day individually or opt for both days, with a combined registration offering that includes accommodation and a buffet dinner. Additionally, the event calls for poster contributions that can advance knowledge about the climate and air quality impacts of increased hydrogen use. Abstract submissions for posters are encouraged until Monday 10th February. Overall, the event aims to foster discussions and insights that can shape a sustainable and beneficial adoption of hydrogen energy systems, ensuring a positive impact on the climate and environment.