Senegal – Monitoring Lead Gasoline Phase Out
- University of Dakar
In 1998, an international framework was established to improve air quality in Sub-Saharan Africa. The first regional conference was organized by the World Bank on June 26th, 2001 in Dakar, Senegal, to discuss the issue of leaded gasoline as a major source of emissions in traffic-heavy towns and cities in developing countries. The harmful health effects of lead exposure in children, such as brain and nervous system damage, prompted the “Dakar Declaration.” This was a joint effort by the World Health Organization and 25 sub-Saharan countries, the oil industry, civil companies, and other international agencies to eliminate leaded gasoline by December 31, 2005.
As part of this project, Blacksmith Institute helped the state Environmental Department and AfricaClean (a local air quality monitoring group) to design and implement a monitoring routine for vehicle emissions. The result was to improve emissions standards and overall air quality.
In July 2005, the African Refining Company reported a voluntary phase-out of leaded gasoline. However, it was important to coordinate efforts among various stakeholders to implement a comprehensive phase-out program, because one last refinery– Société Africaine de Raffinage (SAR)–was to continue producing leaded gasoline for the rest of that year.
The project primarily focused on the control of lead contents in gasoline all over in Senegal with a particular emphasis on traffic-heavy cities. Gasoline samples were collected in different time periods (September 2006, December 2006, and March 2007) in four Senegalese cities (Dakar, Kaolack, Thiès, and Touba). The samples were analyzed by two complementary methods: ICP/MS and CPG/MS, the first highly sensitive and the second capable of identifying the molecular form of lead in gasoline. In addition, the ambient air quality was also monitored to indicate the progress of the phase-out program.
Additionally, the development of national legislation was pursued to control/end informal ULAB operations.
Gasoline sampling results showed that lead was still present in Senegalese gasoline after the ban, but that levels varied across different times and areas. Most importantly, lead content in gasoline in Dakar – home to 75% of Senegalese cars – was much lower. Overall, lead levels in gasoline significantly decreased between September 2006 and March 2007.
BEFORE THE LEADED GAS PHASE-OUT
Collection Average gas lead levels
Pre-2002 800 mg/l
2002 400 mg/l
2003 200 mg/l
AFTER THE LEADED GAS PHASE-OUT
Collection Average gas lead levels
September 2006 0.0105 mg/l
December 2006 0.0005 mg/l
March 2007 0.0001 mg/l
Additionally, atmospheric lead levels decreased in all towns observed to significantly lower than the WHO recommended safe level (0.5 ug/m^3). These results demonstrate that the lead phase-out program in Senegal has been successful overall.
The pursued legislation was also hugely successful. The regulations pursued to end ULAB operations were put into place. Additionally, a list of options was prepared to ensure environmentally sound management of ULAB from formal collection centers and future processing facilities. Lastly, private and public sector partnerships were developed to continue promoting environmentally sound practices.
Trace amounts of lead are still present in stains on gas tanks that were not properly cleaned after the phase-out. A technical committee should determine the viability of using catalytic converters to reduce the emissions output of cars that violate air quality standards (such converters do not function when the vehicle runs on leaded gas, and so they would have been completely useless before the 2005 phase-out).
This air pollution project should be an introduction to more far-reaching initiatives that will seek to transition the diesel buses in Dakar to compressed natural gas or liquefied natural gas fuel. Natural gas bus conversion programs such as those in Mexico City, Bangkok, Cairo, and Beijing will be used as models.