Scientists studying air quality are working to find ways of monitoring ammonia – an increasing species in the atmosphere closely linked to water eutrophication, soil acidity, and biodiversity loss.
Scientists studying air quality are working to find ways of monitoring ammonia – an increasing species in the atmosphere closely linked to water eutrophication, soil acidity, and biodiversity loss. But measuring ammonia is not easy because ammonia can change from gas to particles quickly in the air.
While there are accurate methods to determine ammonia in the lab with the aid of a pump, they are unsuitable for long-term measurements and for large-scale surveys in the field, because of their cost, particularly in terms of manpower, and the need for constant power supply.
To overcome these shortcomings, an alternative method was developed to collect ammonia from the atmosphere without the aid of a pump. The method is called passive sampler, in contrast to previous methods using a pump. The passive sampling method has been widely used to monitor ammonia in the EU, US and China at both national and regional scales. It can provide a simple and cost-effective tool for monitoring ammonia without power requirement.
However, in a study published on May 3, 2020 in Atmospheric Research, scientists test three passive samples used in ammonia collection, and find the ammonia concentrations are all subject to low bias (13.4-27.5%), compared with a standard reference method using a pump to draw air into an active sampler.
Read more at Institute of Atmospheric Physics, Chinese Academy of Sciences
Image: Passive and active samplers for ammonia gas monitoring. (Credit: Yuepeng Pan)
