Nitrous oxide (N₂O) is a powerful greenhouse gas and a major threat to the ozone layer. It is mainly released when people use nitrogen-based fertilizers or burn fossil fuels. Although scientists have made progress in estimating how much N₂O is entering the atmosphere, we still don’t fully understand where all the emissions are coming from or how much is being removed by natural processes. This project brings together different types of data—from air samples, and computer models—to better estimate the global N₂O budget. But N₂O is just one part of the bigger nitrogen puzzle. To really understand its impacts on climate, ecosystems, and food security, we need a complete picture of all the nitrogen moving through the Earth—from farms and cities to rivers, forests, and the ocean. We propose building a comprehensive global nitrogen budget that includes all forms of reactive nitrogen. This will help scientists and policymakers track pollution, improve models, and design better solutions for managing nitrogen in a changing world.