Measurements of sulfur dioxide, ozone and ammonia concentrations in Asia, Africa, and South America using passive samplers

Measurements of gaseous SO2, NH3, and O3 using IVL passive sampler technology were obtained during a pilot measurement program initiated as a key component of the newly established WMO/GAW Urban Research Meteorology and Environment (GURME) project. Monthly measurements were obtained at 50 stations in Asia, Africa, South America, and Europe. The median SO2 concentrations vary from a high of 13ppb at Linan, China, to <0.03ppb at four stations. At 30 of 50 regional stations, the observed median concentrations are <1ppb. Median ammonia concentrations range from 20ppb at Dhangadi, India, to <1ppb at nine stations. At 27 of regional stations, the ambient ammonia levels exceed 1ppb. The median ozone concentrations vary from a maximum of 45ppb at Waliguan Mountain, China, to 8ppb in Petit Saut, French Guiana. In general, the highest ozone values are found in the mid-latitudes, with the Northern hemisphere mid-latitude values exceeding the Southern hemisphere mid-latitude levels, and the lowest values are typically found in the tropical regions. © 2003 Elsevier Science Ltd. All rights reserved.