Recognizing that expanded and improved observations now make possible a broader assessment of global atmospheric chemistry, the WMO Global Atmosphere Watch programme has published a new report on global and regional trends in reactive gases. This group of gases includes such chemicals as surface ozone, nitrogen oxides, carbon monoxide, sulfur dioxide, and volatile organic compounds, many of which are considered to be harmful pollutants.
The first issue of the Reactive Gases Bulletin reviews long-term observation data on volatile organic compounds (VOCs) and discusses past and recent trends. The class of VOCs comprises many individual compounds with different emission sources and chemical properties. The long-term measurement of VOCs through a global network can make it possible to understand changes in regional emissions. This is useful because the oxidation of certain volatile organic compounds can lead to the formation and growth of secondary organic compounds that can take the form of harmful particulate matter, such as the fine particles known as PM2.5 found in urban air pollution.
The Reactive Gases Bulletin was released in April at the Global Atmosphere Watch Symposium, which is held every four years. This year’s event focused on promoting the integration of advances in atmospheric science and observations to support policymaking.
The Reactive Gases Bulletin is the first of a series and is based on many months of research and observations. It is part of a growing suite of WMO information products on the state of the atmosphere. These include greenhouse gas bulletins, Antarctic and Arctic ozone bulletins, aerosols bulletins and, most recently, a new bulletin on airborne dust.
WMO’s Global Atmosphere Watch network consists of atmospheric monitoring stations around the world. A comprehensive quality-management framework ensures that observations adhere to the highest measurement standards and that data from different sources are compatible. This gives confidence in the network’s ability to detect regional differences in concentrations and long-term changes in atmospheric composition.