English: It's everywhere you go, every day, and your health depends on it. It's the air you breathe, and we dramatically affect it, through simple things like driving to work. We have a responsibility to protect the atmosphere and keep it healthy, and that's where Aura comes in. Aura will study the chemistry of the atmosphere: that is, what kind of molecules we find there, how many there are, and how humans’ activities affect those levels. Pollution from one part of the planet can cause dramatic changes to places thousands of miles away, so getting a comprehensive picture is important. And it's not just man-made emissions that affect our lives: volcanic eruptions and solar events can have far reaching effects on climate and air quality. Aura is about better understanding our planet. Its launch will be the culmination of a 15-year international effort to establish the world’s most advanced earth observing system. The more we understand about our atmosphere, the more we can do to protect it in the future.