Air
We understand that our operations release gases and particulates into the atmosphere that may have an effect on people and the environment. These emissions are the result of burning fossil fuels, moving ores and wastes, and smelting metals.
In line with our air quality strategy and our air quality control standard, we constantly review our emissions, look for ways to improve our performance and apply controls to minimise related health or environmental impacts. We also monitor particulate gas and vapour exposure in the workplace, in line with our occupational health standards.
SOx
Our oxides of sulphur (SOx) emissions are mainly generated at our aluminium and copper smelters and our coal and fuel oil fired power stations.
The SOx emissions generated at our copper smelters result from separating metal from sulphur-rich materials in the raw ore we mine. At our aluminium smelters, SOx is released during the production of carbon anodes which are an essential part of the smelting process. SOx emissions from our power stations are a result of the naturally occurring sulphur in the fuel source - coal or fuel oil. The efficiency of the SOx capture equipment used across the Group varies and depends on the smelter's age and type.
SOx emissions have been associated with effects on human lung function and on vegetation, and can also lead to acid rain under specific processes, though this has significantly declined in the last few decades.
NOx
Oxides of nitrogen (NOx) come from burning of fossil fuels. They can cause respiratory problems and contribute to the formation of fine particulates in the atmosphere.
Fluoride
Particulate and gaseous fluoride emissions are generated in aluminium smelters when converting alumina to aluminium, and to a lesser extent, from processes that consume coke and coal.
Fluoride has been associated with effects on human health. It can be taken up by plants, enter the food chain, and affect the strength of teeth and bones.
Particulate emissions
Particulate emissions are recognised as a general nuisance as well as a potential risk to health. Depending on the operation, dust can be generated by fuel combustion, the transfer of raw materials, windblown erosion of exposed areas and stockpiles, wheel generated dust, and during blasting operations.
Particulates smaller than ten micrometres in diameter (PM10) can be retained in the lungs. The composition of PM10 has an important influence on potential health impacts. PM10 from fuel combustion is generally more harmful than PM10 from diffuse sources such as the windblown erosion of exposed areas and wheel generated dust.
Particulate emissions are associated with increased respiratory symptoms such as aggravation of asthma and some lung diseases.
