#0022 Sampling and analysis of airborne ammonia in workplaces of China
Room for Improvement in China’s Ammonia-Monitoring Practices
Ammonia is a colorless gas with a wide variety of industrial applications, including use as a raw material in the synthesis of common industrial products, such as plastics and fertilizers. However, it has an irritating odor and can be corrosive to the eyes, skin, and respiratory tract. Breathing ammonia-contaminated air can cause respiratory damage over the short term and lung disease over time.
Because of these risks, regulatory agencies worldwide need to place limits on the permitted levels of airborne ammonia in the workplace, and protocols for how to properly measure airborne ammonia levels. In the People’s Republic of China, regulators expose sulfuric acid solutions to the air in a workplace and then use a method called Nessler reagent spectrophotometry to measure the amount of ammonia absorbed into the sulfuric acid solution. However, this method has some major limitations, such as the need to measure absorbed ammonia levels on the day of sampling and the fact that the Nessler reagent itself is highly poisonous.
Because of these limitations, we conducted a comparative review of the procedures for collecting and analyzing airborne ammonia samples used by regulatory agencies in Germany, the United States, and China. These comparisons revealed several areas in which the practices used in China could be improved. For example, using a more dilute sulfuric acid solution to sample the air could increase the overall sensitivity of the screening procedures. Chinese regulators could also replace the sulfuric acid with a safer alternative called methanesulfonic acid or even abandon liquid sampling solutions entirely in favor of glass tubes lined with an ammonia-absorbing substance such as a silica gel. We identified various ways to improve conditions for the reaction between ammonia and the Nessler reagent. We also found that regulators could replace Nessler reagent spectrophotometry with a method called ion chromatography, which would facilitate the automation of certain steps and allow regulators to avoid the use of poisonous reagents.
In summary, there are several ways in which Chinese regulators could improve their protocols for monitoring airborne ammonia levels in workplaces. Further studies are needed to identify the optimal methods, but the findings from this review offer important insights into options for improvements.
Link to the original journal article:
https://onlinelibrary.wiley.com/doi/full/10.1002/1348-9585.12100
Title of the paper:
Sampling and analysis of airborne ammonia in workplaces of China
Authors: Z
hizhen Xu, Ling Guo, Dongxu Wang, Zhe Bi, and Zhaohui Fu
