NH3 | Ammonia | Sources and Impact| OIZOM Academy
Channel: Oizom
Date: 06/01/2021

Ammonia is a colorless, toxic, irritating gas with a pungent odour released from decaying organic matter, including  plants, animals,  animal wastes, and fertilizer use.  Prolonged exposure of the NH3 can quickly deaden a person’s sense of smell, making the odor of NH3 an unreliable indicator of its presence. Hence, other means such as use of NH3 monitors is a viable solution to provide adequate warning of hazardous exposure. This article covers information on ammonia, its sources in the ambient air, permissible levels, health and environmental impact, possible corrective measures, need for ammonia monitors as well as different methods of NH3 monitoring.


Ammonia in Atmosphere
NH3 is the most abundant alkaline gas in the atmosphere released naturally from soil from bacterial processes and from decaying organic matter, including plants, animals and animal wastes. 

Sources
The largest source of ammonia emission, globally is agricultural (~85%) including NH3 emissions from ammonia-based fertilizers applications and livestock waste.  Other sources of NH3 include vehicular emissions (specifically catalytic converters in petrol cars), biomass burning, composting of organic matter, landfills, sewage treatment plants, and volatilization from soil and oceans. Industrial sources of NH3 include the fertilizer manufacturing, coke manufacture, pharmaceutical and cleaning products,  fossil fuel combustion, livestock management, and refrigeration methods. 

Health Impact
Exposure to low levels of NH3 can cause coughing as well as irritation to eyes, nose, throat and respiratory tract. NH3 presence is detectable by its pungent odor providing adequate early warning signs, however NH3 also causes adaptation or olfactory fatigue on prolonged exposure thereby damaging one’s sense of smell.

Exposure to high levels of NH3 causes immediate burning of the nose, throat and respiratory tract which can cause airway destruction resulting in respiratory distress or failure and can also lead to death. Children are the most vulnerable to NH3 exposure, due to their greater lung surface area-to-body weight ratios. Additionally, their short height makes them susceptible to inhalation of higher amounts of NH3 vapors which are initially found near ground.




Avoid going to or staying in low lying areas where NH3 is produced or used such as agricultural or poultry farms
Avoid use of  ammonia-containing products, specifically cleaning products in poor ventilated areas. 
Always use appropriate personal protective equipment (PPE) while using NH3 containing products or while going to places where presence of high levels of NH3 is suspected. 
Also, if the presence of NH3 is detected, immediately vacant the area and provide proper ventilation to remove the gas.
Measurement methods of NH3 monitoring
Different working principles for ammonia monitoring in the ambient environment are chemiluminescence, semiconductor, and electrochemistry.

Electrochemical
NH3 monitors working on the electrochemical principle are operated based on the diffusion of ammonia gas into the sensor which results in the production of electrical signals proportional to the NH3 concentration. Therefore, it allows accurate measurement of even low concentrations of NH3, which is essential in NH3 monitoring in the ambient air. 


Reasons why NH3 monitoring is important
NH3 is a very soluble, colorless gas with a strong pungent smell primarily released from decaying organic matter, including  animal wastes and fertilizer use.
NH3 forms secondary particulate matter of ammonium salts (NH4+) by reacting with the acids of SOx and NOx, which move large distances along with the air impacting human health and environment of both local as well as international (transboundary) scales. 
NH3, on contact or when inhaled, rapidly reacts with the moisture containing parts of the body and causes irritation, damage to the cells of eyes, nose, throat and respiratory tract.  Additionally, it plays a significant role in atmospheric deposition of nitrogen to sensitive ecosystems causing acidification and eutrophication of soils and natural waters. 
Prolonged exposure of the NH3 can quickly deaden a person’s sense of smell, making the odor of NH3 an unreliable indicator of its presence. Hence, other means such as use of NH3 monitors is a viable solution to provide adequate warning of hazardous exposure
Real-time monitoring of NH3 levels helps in calculating air quality index to deliver health advisories as well as formulating an action plan to meet standards.