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Cyanides (as HCN) 


Hydrogen cyanide is a gaseous pollutant with the chemical formula of HCN. Sometimes referred to as a prussic acid. It has no colour with the odour of bitter almonds. It is highly flammable and extremely poisonous. 


Hydrogen cyanide is the gaseous form of cyanide and is generated by the combustion of nitrogen- and carbon-containing substances such as wool, silk or synthetic substances like plastics. HCN can also be produced in blast furnaces, gas works and coke ovens. HCN is lighter than air so it will readily disperse up into the atmosphere. 

Environmental Impact 

Hydrogen cyanide is an air pollutant commonly found in urban areas. It is highly toxic and can result in major environmental impacts and public health issues. Inhaling small amounts of cyanide can result in death, spills have led to contaminated water and major fish kills. 


HCN is commonly controlled in combustion processes by improving combustion efficiency. Ventilation systems can be used to remove localised sources of HCN however without abatement these concentrations are emitted to atmosphere. Any exhaust system dealing with cyanides should be corrosion resistant and non-flammable.. 


Alkali Environmental perform periodic measurements of Cyanides in gaseous streams from stationary sources in line with the standard reference method US EPA OTM29:2011. We are currently working towards accreditation for this method whereby the reported results will carry UKAS and MCERTS accreditation where the method can be performed to the standard. 
These measurements are taken using a manual sampling train whereby a single result is obtained for a gas sample taken from the duct. 
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