Airborne emissions have the potential to affect the health, general well being and livelihoods of people and to degrade the environment. Some of Rio Tinto's activities emit sulphur dioxide, fluorides, greenhouse gases and dust.

Given the potential impacts to people and the environment, we need to understand and control our emissions and their effects, and meet our legal requirements.

Environmental sources of dust include moving or stockpiling material, traffic movements on unsealed roads, and stack emissions. Measures are taken to minimise the generation of dust. Dust is recognised as a general nuisance impacting upon amenity. However, more importantly, dust particles under 10 microns in diameter (PM10) are invisible to the naked eye, can be retained in the lungs and are associated with lung diseases, including asthma and industry specific diseases known as pneumoconiosis. In addition to the particles themselves, dust particulates may contain potentially toxic substances on their surfaces; for example, diesel exhaust fume particles may contain polyaromatic hydrocarbons.

The majority of sulphur dioxide emissions from Rio Tinto's operations come from smelters. Metals often occur in ore combined with sulphur, which produce oxides of sulphur in the smelting process. This can be captured and converted to sulphuric acid for use in refining and other industrial purposes. The efficiency of the capture equipment is variable across the Group and relates to the age of the equipment.

Sulphur dioxide and fluoride emissions have been associated with impacts on human health. Sulphur dioxide has been associated with asthma as well as acid rain in the northern hemisphere, whilst fluoride can be taken up by plants and enter the food chain. Rio Tinto aims to have controls in place to minimise any potential health and environmental impacts.

Particulate and gaseous fluoride emissions are mainly generated in aluminium smelters as a by-product of the process of converting alumina to aluminium.

Greenhouse gases are produced through the combustion of fossil fuels, the clearing of land and process emissions, and are implicated in climate change... What greenhouse gases do we produce?

Air emissions performance

Many of Rio Tinto's operations also report emissions information publicly under community 'right to know' emissions programmes such as the Toxic Release Inventory in the US, the National Pollutant Inventory in Australia and the National Pollutant Release Inventory in Canada.

Rio Tinto monitors health in the workplace and has also developed Group-wide occupational health standards, which cover topics such as workplace monitoring and particulate gas and/or vapour exposures. More details.