Health Effects of 1,3-Butadiene
Information on effects
Health Effects.
1,3-Butadiene is, like Benzene, a genotoxic carcinogen and as such there is no safe limit of exposure. Studies have shown that long term exposure can result in cancer, especially of the lymphoid system and blood forming tissues. Little monitoring data currently exists on 1,3-Butadiene and as such EPAQS has recommended a review in 5 years time. EPAQS has set a standard that it believes represents a level at which, for practical purposes the risks are exceedingly small and unlikely to be detectable by any practical method.
Sources.
1,3-Butadiene is a gas at ambient temperature and pressures and trace amounts are present in the atmosphere. The main source of 1,3-butadiene in ambient air derives from the combustion of petrol and other fossil fuels. It is also used in industry, mainly in the production of synthetic rubber for tyres. An emission inventory in 1995 calculates that 67% of total national emissions results from petrol vehicles (Table II.4.2 NAQS).
Standard.
The air quality standard to be achieved by 2005 has been set at 1 part per billion measured as a running annual mean.
Monitoring Results.
The technical difficulties and economic costs of monitoring 1,3-Butadiene have meant no routine monitoring has taken place within the borough. However current information from sites within London and the emission inventory complied by the London Research Council indicate that current levels are below the standard. The Department of the Environment, Transport and the Regions maintain a number of sites nationally that measure for 1,3-Butadiene. The results for the London Bloomsbury site, located in Central London recorded an annual running average of 0.38 ppb for 1994 and 0.36 for 1995.
Compliance with the Standard.
Control measures and the effect of the use of catalytic converters on newly registered cars means that the current measured concentrations are unlikely to increase. The NAQS states in paragraph 14 Chapter II.4 "by 2005 the emissions reductions currently foreseen are likely to be such that the 1 ppb value is attained in virtually all locations." With this information no further assessment of the levels of 1,3- Butadiene is recommended.
