Brussels, 30 June 2003
EU research project proves that personal choice can dramatically improve urban air quality
Stop smoking and leave your car at home. Encouraging people in cities to make simple lifestyle changes, such as using alternative forms of transport to the car, can significantly reduce their exposure to harmful air pollutants. The findings of the first in a series of Europe-wide air quality studies was announced today in Brussels by European Research Commissioner Philippe Busquin and Didier Gosuin, Environment Minister of the Brussels-Capital Region. 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, using 125 volunteers carrying special sensors to monitor their levels of exposure to benzene, a carcinogenic substance produced by traffic and smoking. Similar surveys have also been conducted in Lisbon, Bucharest and Ljubljana.
Announcing the results of the project, 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. 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.”
Leaving the car at home can improve your quality of life
Benzene is a carcinogen responsible among others for leukaemia. It is found in petrol 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. Benzene monitoring therefore points to exposure to other pollutants and is the first carcinogen to be regulated by EU air quality directives. PEOPLE clearly identifies tobacco smoking and traffic emissions as factors increasing levels of exposure. PEOPLE also confirms that the active participation of local authorities and the general public is essential for implementing the EU air quality legislation.
Brussels volunteers get personal with cutting-edge research methods
Some 125 Brussels residents participated in the pilot stage of the PEOPLE project in Brussels on 22 October 2002. Participants were selected according to well-defined criteria: non-smokers unexposed to traffic (control group), smokers, people using private transport, public transport commuters, cyclists and walkers.
Participants carried a sensor for 12 hours to assess their personal level of exposure to benzene. Measurements were also taken over a 24-hour period at a wide range of indoor locations such as homes, offices, shops, schools, bars and restaurants and public transport. Volunteers carried a newly developed passive sampler enabling short-term measurements.
Towards a benzene-free city?
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, median value of 10.8 micrograms per cubic meter; and in cars, median value of 27.5 micrograms per cubic meter.
Outdoor measurements were also taken to assess the levels and distribution of benzene throughout the city. Complementing the passive sampler measurements, data from a monitoring network was used to assess the yearly average concentration of the pollutant.
On the day of the campaign pollution levels in Brussels complied with the yearly average value of 5 micrograms per cubic meter, limit set by Directive 2000/69/EC, except in areas with dense traffic. Measurements from the continuous monitoring network show that benzene levels in Brussels in 2003 as being approximately half those observed ten years ago.
Calling more people to participate in PEOPLE survey
Benzene emissions studies were also conducted in Lisbon (22 October 2003) and more recently in Bucharest and Ljubljana (27 May 2003), and will be followed by further campaigns in Madrid and Bucharest (autumn 2003). 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. PEOPLE will be extended to other toxic pollutants in the future, placing emphasis on particulates. The Commission, in co-operation with local authorities, invites volunteers to participate in the next steps of the project.
More information about the PEOPLE project may be found at:
Summary of research results in Brussels
Outdoor pollution levels
Pollution levels in Brussels, on the day of the campaign, complied with the yearly average value of 5 µg/m3 limit set by Directive 2000/69/EC, except in areas with dense traffic. Maximum exposure zones and benzene distribution levels are presented in Figure 1.
In Brussels, this corresponds to the area between Arts-Loi and Place Schuman, rue de la Loi and rue Belliard, characterised by dense and bottlenecked traffic. Measurements from the continuous monitoring network show that pollution levels on the day of the campaign were low in comparison with the median annual level (35th percentile value). They also show benzene levels in Brussels in 2003 as being approximately half those observed ten years ago.
This is due to several factors: EU regulations limiting car emissions (catalytic exhaust) and reducing benzene content in gasoline from 2 to 1%; improved testing of cars and transport at national level; and various other national and local measures such as air pollution, mobility and city planning/management policies.
Indoor pollution levels
Levels were measured in typical indoor city locations, where people may spend a significant amount of time during the day (Figure 2).
Benzene concentrations in houses of citizens were twice that of the city background air with a median value of 6.4 micrograms per cubic meter. When indoor sources, including tobacco smoke are not present, the outdoor levels determine the measured concentrations at these locations.
Schools and offices
Schools have the lowest benzene concentrations (median value of 1.6 micrograms per cubic meter), perhaps because of the selection of “clean environments” where pollution sources were not present. The low values measured in offices (median value of 3.1 micrograms per cubic meter) are at a similar level as the city background measurements.
Shops and bars
In bars, where tobacco smoke may be present, the benzene concentration was high (median value of 10.8 micrograms per cubic meter). In shops (some of which are smoking locations) the levels are higher than the corresponding city background levels.
The highest levels of concentration were found inside cars (median value of 27.5 micrograms per cubic meter). Frequently cars travel through areas of high pollution considered as hot spot areas. This situation also influences personal exposure, in particular when people travel at rush hour through the city.
The personal exposure measurements represent the average concentrations to which a citizen was exposed. Exposure to benzene was related to a person's life style and the type of environment considered. The main factors that affected benzene exposure were tobacco smoke and the time and mode of travelling (see Figures 3). Clusters were identified from data analysis that corresponded to the different categories of volunteers participating in the study.
The non-smoking sedentary citizens, who acted as control group in the study, present the lowest levels of exposure (median value of 0.6 micrograms per cubic meter). These levels are even lower than the levels observed outdoors in background air.
Smokers are by far the most polluted class of citizens, exhibiting a median value of 7.5 micrograms per cubic meter. The strong variation in concentration levels depends on the number of cigarettes smoked and on the confinement space (e.g. indoor, outdoor).
In situations with the absence of smoking or other indoor pollution sources, the mode of travelling was the main factor affecting personal exposure. Amongst the types of travellers measured, car users are the most exposed group of travellers (median value of 5.2 micrograms per cubic meter). Again this relatively high level can be explained by proximity and length of exposure to emission sources. The level decreased when the travelling media changed. Walkers-cyclists (median value of 4.4 micrograms per cubic meter), public transport (median value of 3.8 micrograms per cubic meter) and the mixed transport category (median value of 3.8 micrograms per cubic meter) present lower values. With respect to public transport users, the exposure was linked to type of transport used, e.g. bus users were more exposed than metro users.
Stepwise multiple regression technique was used to identify factors affecting exposure levels among the volunteers; of which 10% were non-smokers unexposed to traffic, 20% were smokers and 70% were travellers. It was possible to establish the influence of the variables considered in the personal exposure model in relative terms. Figure 4 shows that 44% of the exposure contribution, for the PEOPLE sample of citizens, was due to smoking habits, whilst another 37% was due to travelling and the last 19% of the contribution corresponded to other indoor factors.
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Figure 1: Map showing maximum exposure zones and benzene distribution levels in Brussels on the day of the campaign (22 October)
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Figure 2: Indoor pollution levels on the day of the campaign (22 October)
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Figure 3: Personal exposure levels on the day of the campaign (22 October)
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Figure 4: Relative influence of the variables considered in the personal exposure model
The full report of the measurement campaign will be distributed at the press conference