Carcinogenic Benzene Levels Highest at Rush Hour

BRUSSELS, Belgium, June 30, 2003 (ENS) - To breathe air containing less carcinogenic benzene, stop smoking and leave the car at home. That advice has emerged from the first in a series of Europe wide air quality studies, the results of which were released today. The research focused on 125 volunteers who carried special sensors in Brussels to monitor their levels of exposure to benzene, a carcinogenic substance produced by vehicle traffic and tobacco smoking.

European Research Commissioner Philippe Busquin and Didier Gosuin, Environment Minister of the Brussels-Capital Region announced the study's findings in Brussels today. Busquin said, "The knowledge gained by this important research will help us to shape our decisions on traffic and transport issues and encourage people to make healthier lifestyle choices.”

The first phase of the Population Exposure to Air Pollutants In Europe (PEOPLE) project took place in Brussels during a 12 hour period last October. Smokers, people using private transport, public transport commuters, cyclists and walkers were selected to carry the sensors to assess their personal level of exposure to benzene. Nonsmokers unexposed to traffic made up the control group, who also carried sensors.


Smokers inhale benzene along with their nicotine. (Photo credit unknown)
Measurements were also taken over a 24 hour period at indoor locations such as homes, offices, shops, schools, bars, restaurants, and public transport. Volunteers carried a newly developed passive sampler enabling short term measurements.

The study found that smokers are by far the most polluted class of citizens, exhibiting a median value of 7.5 micrograms of benzene per cubic meter of air. The strong variation in concentration levels depends on the number of cigarettes smoked and on the confinement space, whether indoors or outdoors.

The highest levels of benzene concentration were found inside cars, although pollution levels in Brussels on the day of the research study complied with the yearly average value set by law, except in areas with dense traffic. A median value of 27.5 micrograms per cubic meter was recorded.

Personal exposure to benzene is highest when people travel at rush hour through the city, the study concludes, particularly when cars travel through areas of high pollution considered as hot spot areas.

These results are not due to particularly high levels of benzene in the air on the day of the study. Measurements from the continuous monitoring network show that benzene levels were low in comparison with the median annual level. They also show benzene levels in Brussels in 2003 as about half those observed 10 years ago.


Bumper to bumper rush hour traffic in Brussels (Photo courtesy Travelin-Tigers)
The first carcinogen to be regulated by EU air quality laws, benzene is a carcinogen responsible, among substances, for leukemia. It is found in gasoline and is generated by urban traffic. It is also a good indicator for other traffic pollutants such as carbon monoxide, nitrogen oxides, volatile hydrocarbons and particulate matter.

The tests showed that benzene concentrations in people's houses were twice that of the city background air with a median value of 6.4 micrograms per cubic meter. In bars the benzene concentration was high, with a median value of 10.8 micrograms per cubic meter.

Schools have the lowest benzene concentrations, with a median value of 1.6 micrograms per cubic meter, perhaps because of the selection of “clean environments” where pollution sources were not present, the study states.

The low values measured in offices, with a median value of 3.1 micrograms per cubic meter, are at a similar level as the city background measurements.

The PEOPLE study confirms that the active participation of local authorities and the general public is essential for implementing the EU air quality legislation.


European Research Commissioner Philippe Busquin (Photo courtesy European Commission)
Commissioner Buquin said, “Air quality laws can only truly be effective if they are understood and endorsed by those they are meant to protect European citizens. Research projects such as PEOPLE are key to providing decision makers, environment and health professionals, as well as the general public, with a clearer understanding of urban air pollution and its impact on health."

Benzene emissions studies were also conducted in Lisbon, Portugal on October 22, 2002, and more recently in Bucharest, Romania and Ljubljana, Slovenia on May 27, 2003.

A PEOPLE study of benzene concentrations will take place in Madrid this fall. The study will be extended to other cities in 2004; Belgrade, Dublin, Paris, and Rome have all expressed interest in being associated with the project. The PEOPLE research will be extended to other toxic pollutants in the future, with an emphasis on particulates.