The Air We Breathe

Air is all around us. The oxygen it contains sustains us. Without it, life on Earth would not be possible. It shapes our weather, forms the clouds above us and brings the rain that communities and agriculture depend on. It is ubiquitous and borderless, but it can also harm us. Pollutants and greenhouse gases travel with it, as do fine particles from sand, dust and smoke. Chemical processes taking place within it can damage the ozone layer or generate pollutants that affect health and ecosystems.

This is why atmospheric science matters. It allows us to better understand the complexity of air. By monitoring it, we were able to discover the hole in the ozone layer in the 1980s and take collective global action to protect it and support its recovery.

Through observations on the ground, in the air and from space, atmospheric science has given us the tools to anticipate and track extreme air pollution events such as sand and dust storms, wildfire smoke and other hazards that cross borders and affect millions of people across continents. It has also made it possible for governments and National Meteorological and Hydrological Services (NMHSs) to issue early warnings to protect people and their livelihoods from exposure to hazardous levels of air pollution. It is also atmospheric science that gives decision-makers the information they need to act with confidence.

For decades, the World Meteorological Organization (WMO) and its Members have worked together to observe, understand and monitor the composition of the atmosphere. Through the WMO Global Atmosphere Watch (GAW) Programme and other WMO programmes, NMHSs, research institutions and partners provide sustained, high quality observations that make this possible.

This issue of the WMO Bulletin is dedicated to air and atmospheric science. It shows the breadth of the work of WMO in this field and the importance of sustained observations in turning science into action.

Some of the most important changes in our atmosphere can only be understood through observations sustained over decades. The articles on ozone and greenhouse gases trace the evolution of atmospheric science from early discoveries to today's global monitoring networks. They remind us that long-term observations made it possible to identify threats such as the ozone hole, detect unexpected emissions of ozone-depleting substances and track the continued rise of greenhouse gases in the atmosphere.

The articles on sand and dust storms and wildfire smoke examine how atmospheric science is helping countries better understand, monitor and forecast hazards that can travel across borders. They show how improved observations, forecasting and early warning systems are helping authorities prepare for events that can disrupt transport, threaten public health and affect communities thousands of kilometres from their source.

This issue also brings us closer to the people and places behind the data. The interview with Dr María del Carmen Cazorla Andrade shows us the dedication and perseverance needed to build atmospheric observations from the ground up in under-monitored regions such as Ecuador. The article on the Chacaltaya station in Bolivia takes us high into the Andes, where scientists, technicians and students observe the air from one of the most important high altitude atmospheric monitoring sites in South America.

These stories remind us that observations are not just instruments and numbers. They depend on people, institutions and resources. Many parts of the world still lack the observing infrastructure, technical capacity and sustained resources needed to monitor the atmosphere effectively. This weakens the whole global system. When observations are missing in one region, the consequences are felt everywhere.

The atmosphere connects us all. Hazards do not stop at borders, and neither can the scientific cooperation needed to understand and address them. Through its programmes, observing networks and partnerships, WMO and its Members work to strengthen our collective understanding of the atmosphere.

We rarely think about the air around us until something goes wrong: skies dimmed by smoke, orange hazy days, a coating of fine sand on our cars or air pollution severe enough to keep us indoors. Atmospheric science helps us see what is otherwise invisible, transforming observations into knowledge. And it is knowledge that allows us to act.