Chlorine / chlorine gas (Cl₂)

Description:

Chlorine / chlorine gas (Cl₂) is a gas at room temperature, but in nature it occurs almost exclusively in a combined form, since it is highly reactive with almost all other elements. Exceptions include volcanic gases and the upper layers of the atmosphere, where chlorine gas exists in molecular form.

Combined chlorine, on the other hand, is very common. It is a component of seawater and of table salt (sodium chloride), which is derived from seawater.

In industry, chlorine in liquid and compound form is used in the manufacture of chemicals and pharmaceuticals. For example, it is the starting material for bleaches and disinfectants, as well as for PVC plastic. To this end, it is produced chemically through electrolysis.

In everyday life, chlorine enters the air we breathe mainly through the use of cleaning and disinfecting products. But there are also workplaces, such as swimming pools, where people are exposed to higher concentrations of chlorine gas. Storage facilities for chlorine gas cylinders are also a potential source of danger.

Chlorine damages the respiratory and digestive tracts even at a concentration as low as 0.001%. At concentrations of approximately 0.5% or higher, chlorine gas is fatal to humans. For this reason, chlorine gas containers must always be tightly sealed and stored in safe locations: well-ventilated areas protected from heat, open flames, and moisture.

When using cleaning and disinfecting products, you must strictly follow the instructions on the packaging to avoid irritation or burns.

Airborne chlorine limit values:

Since chlorine has a corrosive effect on the mucous membranes and respiratory tract even at low concentrations, there are legally mandated exposure limits for handling this gas. The occupational exposure limit (AGW) for chlorine is 0.5 ppm. For drinking water, the limit for chlorine is 0.3 mg/l. Chlorinated drinking water loses much of its chlorine in the form of chlorine gas through evaporation. Before drinking it, the water can be completely dechlorinated by boiling it briefly or letting it sit.

Consequences of a concentration that is too high:

When dissolved in water, it is suspected to increase the risk of bladder cancer. For this reason, legal limits are in place for its use. Chlorine also escapes from water in gaseous form.

In its gaseous form, chlorine (Cl₂) is toxic and irritating. Inhaling chlorine gas can cause respiratory problems, dizziness, and nausea. Air with a very high chlorine content causes burns to the mucous membranes and respiratory tract within a few minutes. For this reason, special protective measures are implemented in workplaces where chlorine is handled.

Source of chlorine:

Chlorine can be isolated from its natural compound form through chemical processes. These include, for example, production via chlor-alkali electrolysis. A sodium chloride solution is then separated by an electric current into chlorine and sodium hydroxide.

Sensor used:

Chlorine is measured in the air-⁠Q using an electrochemical sensor. Cl₂ molecules react with the sensor’s surface and generate a measurable current. The sensor used is highly accurate. The disadvantage of this sensor, as with all electrochemical sensors, is cross-reactivity: the sensor reacts strongly to fluorine and bromine, and to some extent to sulfur dioxide, chlorine dioxide, and ozone.

Measure chlorine gas:

Use the air-⁠Q air analyzer to measure chlorine and other gases and indoor air pollutants in real time. The chlorine sensor is available for purchase in the store.