Research on Ammonia Sensors and Their Application in Prevention‑Control of Industrial Toxic and Hazardous Gases
Research on Ammonia Sensors and Their Application in Prevention‑Control of Industrial Toxic and Hazardous Gases
With the improvement of people’s quality of life and the rapid growth of the industrial economy, ammonia emitted into the atmosphere from various sectors across China has gradually increased in recent years. The rising ammonia concentration is exerting an increasingly prominent impact on the climate. On the one hand, atmospheric ammonia reacts with gaseous pollutants such as sulfur dioxide and nitrogen oxides to generate secondary aerosol particles. These particles absorb and scatter light, lowering atmospheric visibility. On the other hand, ammonia released into the atmosphere acts as a greenhouse gas and affects atmospheric temperature. Consequently, the market demand for gas‑sensing devices keeps growing. Research and development of gas sensors, especially ammonia sensors for toxic and harmful gas detection, have achieved rapid advancement.
Ammonia is a colourless gas with a strong pungent odour. It is lighter than air and highly soluble in water, forming an alkaline aqueous ammonia solution. In laboratories, ammonia is commonly prepared by heating a solid mixture of ammonium chloride and slaked lime, with calcium chloride and water as by‑products.
Ammonia plays an important role in industrial processes, yet it can act as a silent hazard in homes and offices. Short‑term inhalation of large amounts of ammonia may cause symptoms including lacrimation, sore throat, hoarseness and cough, often accompanied by dizziness and nausea. Severe cases may develop pulmonary oedema and acute respiratory distress syndrome. Excessive or long‑term ammonia exposure may lead to skin pigmentation or finger ulcers in some individuals. Once inhaled into the lungs, ammonia readily passes through the alveoli into the bloodstream, binds with haemoglobin and impairs oxygen‑transport capacity. For this reason, alkaline substances inflict deeper and more severe tissue damage than acidic substances. High blood ammonia concentration may further trigger cardiac arrest and threaten human life. Where does ammonia in our work and living environments originate?
According to relevant experts, indoor ammonia mainly stems from concrete admixtures used in building construction, falling into two primary sources. The first source is urea‑based concrete antifreeze added to cement for winter construction. Ammonia is released slowly from laminates and cement, so it persists indoors for an extended period; this phenomenon is more common in northern China. The second source is high‑alkali concrete expanding agents and early‑strength agents applied to accelerate concrete setting, which constitute the major cause of ammonia pollution in southern China. In addition, indoor ammonia may come from interior decoration materials. For instance, ammonia water is widely adopted in additives and brightening agents for furniture finishing and has become a commonplace product in building‑material markets.
Ammonia has a sharp irritating odour. Its density is 0.7710 kg/m³, with a relative density of 0.5971 (air = 1.00). It can be easily liquefied into a colourless liquid by pressurisation at ambient temperature (critical temperature: 132.4 °C; critical pressure: 11.2 MPa, equivalent to 112.2 atmospheres). It also readily solidifies into snow‑like solids with a melting point of −77.75 °C. Ammonia dissolves in water, ethanol and ether. At high temperatures, it decomposes into nitrogen and hydrogen and exhibits reducing properties. In the presence of catalysts, ammonia can be oxidised into nitric oxide. It is utilised in the production of liquid ammonia, aqueous ammonia, nitric acid, ammonium salts and amines. Synthesised directly from nitrogen and hydrogen, ammonia burns the mucous membranes of the skin, eyes and respiratory tract. Severe inhalation can result in pulmonary swelling and even death.
Since health‑hazardous ammonia may exist around our work and living spaces, effective mitigation measures should be adopted. Ammonia sensors are deployed at this stage to monitor ambient ammonia concentration. Through interlocked processing systems, environmental improvement and hazard‑protection objectives can be realised.
Among current gas‑sensor detection applications, ammonia‑sensor‑element‑based measurement represents a widely‑adopted sensing solution with substantial market demand. Simply put, ammonia sensors work on the electrochemical principle: the concentration of target gas is obtained by measuring the magnitude of induced current.
The British‑imported DDS electrochemical ammonia sensor, a core product of
Shenzhen Wuliang Sensor Technology Co., Ltd., operates without bias voltage. Featuring convenient deployment and high cost‑performance, it serves as an ideal and reliable gas‑sensing solution for personnel working in harsh conditions.
Key Features of Ammonia Sensors
‑ Measuring range: optional 0‑100 ppm, 0‑300 ppm, 0‑1000 ppm‑ Overload resistance: 200 ppm, 500 ppm and 1500 ppm respectively for each range‑ High stability; Series‑4 or Series‑7 versions available‑ Strong environmental adaptability
Ammonia sensors mainly detect and display ammonia gas concentration. Corresponding gas alarm instruments adopt microprocessors as control units and high‑performance electrochemical detection sensors, delivering high sensitivity and fast response. When ammonia concentration exceeds safe thresholds, audible alarms will be triggered timely. Such systems generally consist of gas alarm controllers and gas alarm detectors. They are extensively deployed in metallurgy, petroleum, petrochemicals, chemical engineering, light industry, coking, municipal engineering, coal‑gas industries, pharmaceutical manufacturing, sewage treatment and many other special sectors.
To sum up, ammonia is a substance with both valuable industrial applications and notable risks. Despite its vital functions across multiple fields, its biological toxicity has been well‑documented by scientific research, making it a non‑negligible health threat to human beings. Its adverse environmental impacts also deserve greater attention. With continuous technological iteration of gas sensors, new applications and requirements will inevitably keep emerging. This drives sustained development of the gas‑sensor industry and delivers more eco‑friendly, safe, healthy, convenient, innovative and valuable user experiences, bringing benefits to the general public.
