Ammonia (NH3) has been recognized as a critical contributor to air pollution not only by eutrophication and acidification of land and fresh waters, but also by the formation of aerosols with acidic pollutants such as sulfur dioxide (SO2) and the oxides of nitrogen (NOx) to produce the secondary particulate matter (PM) in the atmosphere. These particulate ammonium species degrade the quality of air and increase the health risk to people living in the polluted regions. Tracing and controlling the emission of NH3 are important to reduce PM2.5 and PM10 in the air. The agriculture activities including usage of nitrogen-based fertilizers, the industrial and traffic emissions are believed to be responsible for the increase of NH3 concentration in the atmosphere. Limited ammonia monitoring is currently a barrier for an in-depth understanding of the vital role of NH3 in PM formation during pollution events.
Here we present a high-precision gas analyzer to measure ammonia concentration with new developments to specifically overcome the technical difficulties associated with real-time NH3 monitoring. Its compact and rugged design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous measurement of atmospheric NH3 level. The urban NH3 monitoring is conducted during the field deployments of the Picarro G2103 ammonia analyzers in two cities located in China and in South Korea. The campaign demonstrates the fast response to the NH3 concentration change in ambient air provides reliable and valuable real-time information about critical local NH3 changes.