Sulfur Dioxide (SO₂)

Unrefined hydrocarbons are made up mainly of hydrogen and carbon, but also contain sulfur compounds. This is why their combustion generates sulfur dioxide (SO₂) emissions, which have an acidifying effect on air and water. Sulfur compounds can also cause foul odors.

Several years ago, we launched a program to reduce our overall SO₂ emissions and prevent occasional peaks in SO₂ levels, which are a source of discomfort for our neighbors. The results are already impressive. Aggregate SO₂ emissions from our refineries have declined by 48% since 2004.

The number of sulfur dioxide peaks has also been reduced, thanks to an ongoing effort begun several years ago, which is based on:

• Forecasting and modeling atmospheric emission dispersion, using a tool that enables us to adjust unit operation and shorten response times, which has already been installed at the Donges, Normandy and Provence refineries in France.
• Targeting spending to upgrade the plants with the highest emissions. In 2010, for example, a high-pressure gas stripper was brought on stream at the Feyzin refinery.
• Heightened vigilance by operators, who are being asked to monitor specific indicators, follow tighter procedures and adopt best practices.

Nitrogen Oxides (NOx)

All combustion processes involving air release nitrogen oxides. In the presence of sunlight, these compounds are precursors to ozone formation in the lower layer of the atmosphere (troposphere). Ozone is an oxidant that is harmful to health and the environment.

Our Chemicals business has succeeded in stabilizing the NOx emissions of its boilers and furnaces. Efforts continue in this area, both in the Chemicals business and across Total, based on:

• Prevention measures, such as the gradual deployment of low-NOx burners at certain sites and, since 2005, at all new or upgraded Upstream units.
• Corrective measures, such as the installation of flue gas denitrification and urea production systems. The Vlissingen (Netherlands), Leuna (Germany) and Provence (France) refineries have all been retrofitted with flue gas denitrification systems using urea or ammonia as a reagent.

In addition, we market AdBlue, which reduces the NOx emissions in diesel engine exhaust by 85%.

Volatile Organic Compounds (VOCs)

Volatile organic compounds (VOCs) pose three types of potential risks — photochemical pollution, health risks and odors. Eliminating VOCs is a complex challenge due to the great variety of sources, compounds and diffusion situations involved.

We combat VOC emissions in a number of ways:

• By equipping our sites, right from the project design phase, with a recovery network linked to most sources of VOC emissions. In recent years, we have also installed floating roofs on tanks at our petrochemicals sites, containing such products as benzene and gasoline, to limit VOC emissions at the source.
• By stepping up and optimizing the use of vapor recovery systems during loading and offloading. This type of equipment was installed at the Carling and Gonfreville petrochemical plants in France, for example, to minimize benzene emissions.
• By conducting regular detection campaigns using infrared cameras and “sniffer” systems.