Monitoring of waterborne pathogens in surface waters in amsterdam, the Netherlands, and the potential health risk associated with exposure to cryptosporidium and giardia in these waters.

The water in the canals and some recreational lakes in Amsterdam is microbiologically contaminated through the discharge of raw sewage from houseboats, sewage effluent, and dog and bird feces. Exposure to these waters may have negative health effects. During two successive 1-year study periods, the water quality in two canals (2003 to 2004) and five recreational lakes (2004 to 2005) in Amsterdam was tested with regard to the presence of fecal indicators and waterborne pathogens. According to Bathing Water Directive 2006/7/EC, based on Escherichia coli and intestinal enterococcus counts, water quality in the canals was poor but was classified as excellent in the recreational lakes. Campylobacter, Salmonella, Cryptosporidium, and Giardia were detected in the canals, as was rotavirus, norovirus, and enterovirus RNA. Low numbers of Cryptosporidium oocysts and Giardia cysts were detected in the recreational lakes, despite compliance with European bathing water legislation. The estimated risk of infection with Cryptosporidium and Giardia per exposure event ranged from 0.0002 to 0.007% and 0.04 to 0.2%, respectively, for occupational divers professionally exposed to canal water. The estimated risk of infection at exposure to incidental peak concentrations of Cryptosporidium and Giardia may be up to 0.01% and 1%, respectively, for people who accidentally swallow larger volumes of the canal water than the divers. Low levels of viable waterborne pathogens, such as Cryptosporidium and Giardia, pose a possible health risk from occupational, accidental, and recreational exposure to surface waters in Amsterdam.

Dioxin and dioxin-like PCB exposure of non-breastfed Dutch infants.

The exposure of humans to PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like PCBs (dl-PCBs, i.e. polychlorinated non-ortho and mono-ortho biphenyls) occurs predominantly via the intake of food. Young children have a relatively high intake of these substances, due to their high food consumption per kilogram body weight. As the exposure of non-breastfed infants to these compounds has not been assessed before in The Netherlands, we studied the dietary intake of 17 PCDD/Fs and 11 dioxin-like PCBs in 188 Dutch non-breastfed infants between 4 and 13 months. The food intake of the infants was assessed by a 2-d food record. From these data PCDD/F and dioxin-like PCB intake was calculated using PCDD/F and dioxin-like PCB concentrations of food products sampled in 1998/1999 in The Netherlands. The long-term PCDD/F and dioxin-like PCB exposure of the infants was calculated using the statistical exposure model (STEM). For infants of 5 months the chronic exposure to PCDD/F and dioxin-like PCB was 1.1pg WHO-TEQ (toxic equivalents) per kilogram body weight (bw) per day (95th percentile: 1.7pg WHO-TEQ/kg bwxd), which mainly originated from infant formula and vegetables and increased to 2.3pg WHO-TEQ/kg bwxd (95th percentile 3.7pg WHO-TEQ/kg bwxd) for infants just over 1 year old eating the same food as their parents. The percentage of formula-fed infants with an exposure exceeding the TDI of 2pg WHO-TEQ/kg bwxd was 5% at 5 months, 49% at 9 months and 64% at 12 months.

Effects of fine and ultrafine particles on cardiorespiratory symptoms in elderly subjects with coronary heart disease: the ULTRA study.

The ULTRA Study, a study investigating the association between fine and ultrafine particulate air pollution and cardiorespiratory health, was conducted during the winter of 1998-1999 in Amsterdam, the Netherlands; Erfurt, Germany; and Helsinki, Finland. At each study center, a panel of elderly subjects with coronary heart disease recorded cardiac and respiratory symptoms in a diary. Exposure to ambient air pollution was characterized by measuring daily mass concentrations of particles smaller than 10 micro m (PM(10)) and 2.5 micro m (PM(2.5)), number concentrations of ultrafine particles (NC(0.01-0.1)), and gases. Odds ratios for the relation of symptoms to air pollution, adjusted for time trend, respiratory infections, and meteorologic variables, were mostly homogeneous across the centers. No association was found between air pollution and chest pain. A 10- micro g/m(3) increase in PM(2.5) was positively associated with the incidence of shortness of breath (odds ratio (OR) = 1.12, 95% confidence interval (CI): 1.02, 1.24) and with avoidance of activities (OR = 1.09, 95% CI: 0.97, 1.22). NC(0.01-0.1) was only associated with the prevalence of avoidance of activities (OR = 1.10, 95% CI: 1.01, 1.19). In conclusion, PM(2.5) was associated with some cardiac symptoms in three panels of elderly subjects. PM(2.5 )was more strongly related to cardiorespiratory symptoms than ultrafine particles were.

Daily mortality and air pollution along busy streets in Amsterdam, 1987-1998.

Time-series studies on the association between daily mortality and air pollution levels have been criticized because they use background air pollution measurement sites to estimate exposure of the whole population, including those living along busy roads. To evaluate whether the exposure of people living along busy roads is estimated with error, we calculated separate effect estimates with separate exposure estimates using background and traffic-influenced measurement stations. We used Poisson regression analysis with generalized additive models to correct for long-term trends, influenza, ambient temperature and relative humidity, and day of the week. Black smoke and nitrogen dioxide were associated with mortality (relative risk of 1.38 and 1.10, respectively, for an increase of 100 microg/m3 on the previous day). Effect estimates were larger in the summer and in the population living along busy roads. Effect estimates were also larger using background stations rather than traffic stations. Overall, we found differences in the association between mortality and air pollution using different methods of exposure assessment; these differences are attributable to exposure misclassification for populations living along busy roads.

Differences among black smoke, PM(10), and PM(1.0) levels at Urban Measurement Sites.

n Amsterdam, the Netherlands, we measured airborne particulate matter (PM) during winter 1998-1999, taking daily average measurements at an urban background site, at a busy street, and at a motorway. Comparison of black smoke, PM(10), and PM(1.0) levels showed that daily averages were highly correlated over time. Median daily concentrations were elevated at sites affected by traffic. The highest increase relative to the background in median daily concentration was noted for black smoke at the motorway (300%), whereas for PM(10) and PM(1.0) the increase was only 37% and 30%. These results indicate that mass measurements of ambient particulate matter underestimate the exposure to particles generated by traffic.

Acute effects of air pollution on respiratory health of 50-70 yr old adults.

The aim of this study was to investigate the association between daily changes in respiratory health and air pollution in 489 adults, aged 50-70 yrs, with and without chronic respiratory symptoms, living in urban and nonurban areas in the Netherlands. Subjects were selected from the general population with a screening questionnaire. During three consecutive winters starting in 1992/1993, peak expiratory flow (PEF) and respiratory symptoms were registered in a daily diary. Daily measurements of particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10), black smoke (BS), sulphate, sulphur dioxide (SO2) and nitrogen dioxide (NO2) were conducted. The difference in PM10, BS and sulphate concentrations between urban and nonurban areas was small, but there was more contrast in the concentrations of SO2 and NO2. In symptomatic subjects from urban areas, PM10, BS, sulphate and SO2 concentrations were associated with the prevalence of large decrements in morning PEF (>20% below the median). BS in particular was also associated with upper respiratory symptoms (URS). The magnitude of the effect estimates was in the order of an 80% increase in PEF decrements and a 20% increase in URS for a 40 microg x m-3 increase of the same day BS concentration. In symptomatic subjects from nonurban areas, no consistent associations between air pollution and health indicators were observed. However, the differences in effect estimates between urban and nonurban symptomatic panels were small and nonsignificant. In nonsymptomatic adults from both areas, no consistent pattern of associations with air pollution was found. In conclusion, air pollution effects were only found in symptomatic adults in the urban areas.

[Thiomersal in gammaglobulin for pregnant travellers may not be safe for the fetus. National Coordination Center for Travel Advisory]. / Thiomersal in gammaglobuline voor zwangere reizigers mogelijk niet veilig voor de foetus.

It is not advisible to use thiomersal-containing gammaglobulin preparations for the prevention of hepatitis A in pregnant women. The current preparation of Sanquin-Centraal Laboratorium voor de Bloedtransfusiedienst will yield per 5 ml about 285 micrograms of ethylmercury. This exposure to ethylmercury may not be safe for the foetus and alternatives without ethylmercury are readily available.

Acute effects of urban air pollution on respiratory health of children with and without chronic respiratory symptoms.

OBJECTIVES: To investigate to what extent different components of air pollution are associated with acute respiratory health effects in children with and without chronic respiratory symptoms. METHODS: During three consecutive winters starting in 1992-3, peak expiratory flow (PEF) and respiratory symptoms were registered daily in panels of children of 7-11 years old with and without symptoms, living in urban areas with high traffic intensity in The Netherlands. Simultaneously, panels of children living in non-urban areas were studied. Daily measurements of particles with aerodynamic diameter < 10 microns (PM10), black smoke (BS), sulphate, SO2, and NO2 were performed in both areas. RESULTS: The contrast in particle concentrations (PM10, BS, and sulphate) between urban and non-urban areas was small, but there was more contrast in the concentrations of SO2 and NO2. In children with symptoms from both areas, significant associations were found between PM10, BS, and sulphate concentrations and the prevalence of symptoms of the lower respiratory tract (LRS) and decrements in PEF. Particle concentrations were also associated with use of bronchodilators in the urban areas, but not in the non-urban areas. After stratification by use of medication, stronger associations were found in children who used medication than in children who did not use medication. The magnitude of the estimated effects was in the order of a twofold increase in the use of bronchodilators, a 50% increase in LRS, and an 80% increase in decrements in PEF for a 100 micrograms/m3 increase in the 5 day mean PM10 concentration. In children without symptoms, significant associations were found between concentrations of PM10 and BS and decrements in PEF in both areas, but these associations were smaller than those for children with symptoms. No associations with respiratory symptoms were found. CONCLUSIONS: The results suggest that children with symptoms are more susceptible to the effects of particulate air pollution than children without symptoms, and that use of medication for asthma does not prevent the adverse effects of particulate air pollution in children with symptoms.

Acute effects of summer air pollution on respiratory health of asthmatic children.

In the early summer of 1995, the acute respiratory effects of ambient air pollution were studied in a panel of 61 children, ages 7 to 13 yr, of whom 77% were taking asthma medication. Peak flow was measured twice daily with MiniWright meters at home and the occurrence of acute respiratory symptoms and medication use was registered daily by the parents in a diary. Exposure to air pollution was characterized by the ambient concentrations of ozone, PM10, and black smoke. During the study period, maximal 1-h ozone concentrations never exceeded 130 microg/m3, and 24-h black smoke and PM10 concentrations were never higher than 41 and 60 microg/m3 respectively. Associations of air pollution and health outcomes were evaluated using time series analysis. After adjusting for pollen, time trend, and day of the week, black smoke in particular was associated with acute respiratory symptoms and with medication use. Less strong associations were found for PM10 and ozone. These results suggest that in this panel of children, most of whom had asthma, relatively low levels of particulate matter and ozone in ambient air are able to increase symptoms and medication use.

Cockroach allergen in house dust.

The cockroach allergen (Bla g 1) content was determined in the floor dust of 46 homes with recent cockroach extermination in Amsterdam, The Netherlands. IgE antibodies to Blattella germanica, house-dust mite, cat dander, dog dander, and a mixture of molds were determined in venous blood samples of 46 children (4-12 years) and one of their biologic parents (24-54 years). Specific IgE to cockroach was also determined in a sample of the general population studied in a previous case-control study, one group (n = 20) with three groups (n =76) without history of cockroach infestation of the home. Cockroach allergen was detected in floor dust from 44% of the homes, with levels up to 3899 ng Bla g 1/g. Seven of the 46 adults and only one of the 46 children studied had positive RAST to cockroach. Geometric mean cockroach allergen concentrations in living room and master bedroom of sensitized adults were similar to those of nonsensitized adults. In the groups of children without a history of cockroach infestation of the home, positive RAST against cockroach was observed in 16% of the children with respiratory symptoms, in 4% of the children without respiratory symptoms, and in 48% of the children with two or more positive RAST to other allergens. Of the 18 children with positive RAST against cockroach, only one had a history of cockroach infestation of the home and 16 (89%) had also positive RAST against house-dust mite.

[Cancer incidence in the Schiphol area in 1988-1993]. / Incidentie van kanker in de omgeving van Schiphol in 1988-1993.

OBJECTIVE: To calculate the cancer incidence in the region surrounding Schiphol. DESIGN: Descriptive epidemiological study based on cancer registry data. SETTING: Comprehensive Cancer Centre Amsterdam. The Netherlands. METHODS: Using noise levels expressed as Kosten-cenheden (Ke) of the air traffic around Schiphol (Amsterdam International Airport) as well as 4-digit postal code areas, two study areas were defined, a central area and an adjacent zone. All cancer cases diagnosed in 1988-1993 in the study areas were selected from the population-based Amsterdam Cancer Registry. Observed numbers of cancer cases were compared with expected numbers on the basis of national and regional cancer incidence rates. RESULTS: Cancer incidence (4535 cases) in 1988-1993 in the Schiphol region was slightly higher than national incidence rates (observed/expected (O/E) ratio: 1.93; 95% confidence interval; 1.00-1.06) and almost equal to regional rates. This was largely due to relatively high rates for breast (O/E ratio: 1.08) and prostate (O/E ratio: 1.11) cancer in the Schiphol region as well as in the total area covered by the Amsterdam Cancer Registry. In addition, leukaemia, lymphoma/multiple myeloma and bladder cancer were more frequent, the last-named especially in males. The incidence of cancer of the respiratory tract was not the same in the central area and the adjacent zone. As compared with national rates, it was increased in the central area (O/E ratio: 1.19), while it was decreased in the adjacent zone (O/E ratio: 0.86). The incidence of cancer of all sites (O/E ratio: 1.10) was also increased in the central area, largely due to smoking related cancers. CONCLUSION: During 1988-1993, cancer incidence in the area surrounding Schiphol was a little higher than the national incidence rates and almost equal to the regional incidence. We could not demonstrate an association between air traffic and increased cancer risk. It is most likely that the differences for certain types of cancer as well as those between the two study areas were due to differences in lifestyle, such as smoking habits.

Possible relevance of pigeons as an indicator species for monitoring air pollution.

Wild city pigeons were caught at four different locations in the Netherlands to represent areas of high (Amsterdam-high), moderate (Amsterdam-medium), and low (Maastricht and Assen) traffic density. It is assumed that local ambient air pollution decreases as a function of traffic density. In these pigeons levels of polycyclic aromatic hydrocarbon (PAH)-DNA adducts, oxidative DNA damage, and heavy metal residues were determined in kidney, lung, liver, and blood (no adduct analysis in blood). The contribution of leaded gasoline to total body lead content was estimated by measuring concentrations of Pb and its isotopes in blood. We also analyzed samples of ambient air particulate matter for PAH and heavy metal concentrations at the four different locations. Interregional differences in heavy metals in ambient air particulate matter were reflected relatively well by pigeon body loads. The higher lead and cadmium concentrations in blood, kidney, liver, and lung were found in the Amsterdam high traffic density area, followed by Amsterdam medium, Assen, and Maastricht. A high Pb concentration in blood coincided with relatively low 206Pb/207Pb values, indicating a high contribution of leaded gasoline to total blood Pb concentrations in pigeons from the Amsterdam high traffic density area. Significantly enhanced blood zinc values were found in pigeons from both locations in Amsterdam compared to pigeons from the other two areas. However, no differences in Zn tissue levels between the four different groups were found. Oxidative DNA damage, determined as the ratio of 7-Hydro-8-oxo-2'-deoxyguanosine/ deoxyguanosine, in pigeon liver was highest in Amsterdam-high, followed by Assen (low traffic density). Pb content, but not the Cd content, was positively associated with oxidative DNA damage in liver tissue. In lung tissue, a negative correlation was found between oxidative DNA damage and Zn content. These results indicate that the carcinogenic potential of Pb might be ascribed to oxygen radical formation, whereas Zn plays a protective role against oxidative DNA damage. Places with high and medium traffic density could be clearly discriminated on the basis of PAH levels in the ambient air. The PAH content in particulate air samples was not, however, reflected in total PAH-related DNA adduct levels because no differences could be observed in tissue adduct levels in pigeons from the four different locations. Our results indicate that wild city pigeons can be used as biological indicators of exposure to heavy metal pollution in outdoor air.

[Blood lead levels in young children in The Netherlands]. / Concentraties lood in het bloed van jonge kinderen in Nederland.

OBJECTIVE: Determination of lead content in blood (Pb-B) of young children in the Netherlands, to assess the influence on Pb-B of the ambient environment and to verify a surmised decrease of Pb-B. DESIGN: Cross-sectional study. SETTING: Centres and suburbs of Rotterdam and Amsterdam villages in the Geul Valley (Limburg), neighbourhoods in urban areas in Limburg and Flevoland. METHOD: Randomly selected children aged 1-6 years, residing for at least 2 months in the aforementioned areas, provided a venous blood sample, in which Pb-B was determined. RESULTS: Pb-B of 559 children investigated, varied from 20 micrograms/l through 224 micrograms/l and showed no clear association with age. Mean Pb-B of girls (48.5 micrograms/l) was slightly lower than that of boys (52.5 micrograms/l). Mean Pb-B was highest in children from the centre of Rotterdam, followed by that in children from the centre of Amsterdam, the suburbs of Rotterdam and Amsterdam, the Geul Valley and Lelystad, while children from Flevoland and the neighbourhoods in urban areas in Limburg had the lowest Pb-B. In children from the city centres Pb-B had decreased since 1979 by 62% (Amsterdam) and since 1981 by 52% (Rotterdam). In children from the suburbs of these cities these decreases amounted to 57% and 39% respectively. CONCLUSION: Pb-B of young children in the Netherlands has decreased to a mean of 64 micrograms/l in children from the city centres and to a mean of 45 micrograms/l in children living outside the city centres. Among the children from the inner cities, 2.7% had a Pb-B higher than 150 micrograms/l and 6.7% a Pb-B higher than 100 micrograms/l.

Infant respiratory symptoms in relation to mite allergen exposure.

The relationship between the Dermatophagoides pteronyssinus (Der p) I content of house dust and the respiratory symptoms reported for young infants was studied. One hundred and four infants, aged 3-15 months, were selected during July-September 1993 through the Dutch postnatal health care service, using a short screening questionnaire to identify mothers with respiratory allergy to house dust and/or pets. Forty-eight were selected from this group of mothers ("high risk" infants) and 56 infants were selected when neither of the parents reported allergy or chronic respiratory symptoms ("low risk" infants). All homes were visited in October 1993. Dust samples were collected from the infant's mattress and from other places in the home, and the Der p I content was measured in dust extracts. The results indicate that on more than half of the mattresses, the Der p I level was over 2,000 ng.g-1, the level suggested to be associated with an increased risk of sensitization. Information on respiratory symptoms ("wheeze" and "prolonged cough") experienced since birth was obtained by questionnaire from one of the parents on the dust sampling day. The occurrence of respiratory symptoms in the infants appeared to be positively related to the Der p I concentration of the dust. Although no objective measurements of respiratory symptoms were available, the results of this study suggest that exposure to mite allergen in early life may lead to respiratory symptoms that are suggestive of airway obstruction in the first year of life.

Exposure to polycyclic aromatic hydrocarbons among Dutch children.

We determined the urinary 1-hydroxypyrene (1-HP) concentration and the creatinine-adjusted 1-HP concentration in 644 randomly selected Dutch children, aged 1-6 years and living in five areas with roughly different levels of polycyclic aromatic hydrocarbons (PAHs) in soil and ambient air. The presence of other factors that might influence the exposure to PAHs was studied using a questionnaire. To evaluate the reliability of a single urinary 1-HP determination, measurements were repeated after 3 weeks for approximately 200 children. The mean urinary 1-HP content of the total study population was 2.06 nmol/l. This varied from 1.58 nmol/l in the reference area (Flevoland) to 2.71 nmol/l in the valley of the Geul. Only indoor sources of PAHs showed a small, positive association with urinary 1-HP. The urinary 1-HP concentrations of children from the valley of the Geul were higher (p < 0.01) and those of children from a suburb of Amsterdam were lower (p < 0.01) than those of children from the reference area. The possible ambient environment-related differences were probably too small to be detected in the variations of the intake of PAHs from the daily diet. The reliability of a single 1-HP measurement was low. Similar results were obtained with the creatinine-adjusted data. In one neighborhood built on coal-mine tailings, the urinary 1-HP content in children was weakly but positively associated with the PAH content in the upper soil layer of the garden of their homes. However, this association was not found for the children from the other neighborhood built on coal-mine tailings and with similar PAH levels in soil.

Air pollution and daily mortality in Amsterdam.

Few data are available on the association between the present low levels of air pollution in Western Europe and mortality. Daily mortality counts and the concentrations of black smoke, inhalable particles (PM10), sulfur dioxide (SO2), carbon monoxide (CO), and ozone (O3) were available for Amsterdam from 1986 to 1992. We used Poisson regression analysis to control for seasonal and other long-term temporal patterns. Black smoke and PM10 were positively associated with increased risk of mortality. The relative risk for a 100-micrograms per m3 increase in black smoke on the same day was 1.19 [95% confidence interval (CI) = 1.02-1.38], and that for a 100-micrograms per m3 increase in PM10 was 1.06 (95% CI = 0.99-1.14). The relative risk for individuals over 64 years of age was higher. We found no consistent association between the levels of SO2 or CO and daily mortality, but ozone lagged 2 days was positively associated with daily mortality. The effect of particulates on acute mortality was independent of these pollutants. The results of the present study are consistent with the relation reported between particulate air pollution and daily mortality in other communities in Europe and the United States.

Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms.

BACKGROUND: Allergen exposure in early childhood is thought to be important for sensitization and subsequent development of asthma. Not much is known, however, about exposure of young children to allergens in the home. OBJECTIVES: This study was designed to document dust mite allergen exposure in young children, and to determine whether infants from atopic mothers (= 'high-risk' infants) are exposed to lower concentrations of house dust mite allergen than infants from non-atopic parents (= 'low-risk' infants). METHODS: Dust samples were taken in the homes of 104 infants (48 'high-risk' and 56 'low-risk' infants, selected by questionnaire) aged 3-15 months, from floors in different rooms and from the child's mattress surface. RESULTS: The majority of the infants were found to be exposed to Der p I concentrations of more than 2000 ng/g in dust collected from the surface of their mattresses. Lower Der p I concentrations were found in mattress surface dust from the beds of infants from atopic mothers than of infants from non-atopic parents. Also, lower Der p I concentrations were found in floor dust from the homes of infants from atopic mothers. Infant beds equipped with new mattresses, new blankets and top plastic sheeting had significantly lower Der p I concentrations than beds equipped with used mattresses and blankets, without top plastic sheeting. CONCLUSIONS: Young children in the Netherlands are exposed to significant concentrations of Der p I in mattress surface dust. Allergic parents appear to provide their children with environments somewhat less rich in mite allergen than non-allergic parents.

Damp housing and childhood respiratory symptoms: the role of sensitization to dust mites and molds.

In 1990, a case-control study was conducted in the Netherlands into the association between damp housing, childhood respiratory symptoms, and sensitization to house dust mites and mold allergens. In this study, 259 children with chronic respiratory symptoms and 257 control children were involved. Total serum immunoglobulin E (IgE) and specific IgE against house dust mites and a mixture of molds were determined. A visual inspection for signs of home dampness was performed in all homes. A questionnaire was given to the parents of the children to elicit information about the presence of signs of dampness in the previous 2 years and about risk factors for childhood respiratory disease. In the case group, 94 children had elevated serum IgE levels to house dust mites and 24 children to the mixture of molds. In the control group, house dust mite allergy was found in 31 children and mold allergy in two children. In a crude analysis, cases were slightly more likely to have been living in homes where damp or mold was reported or observed than were the controls. In cases as well as controls, home dampness was associated with increased sensitization to dust mites and molds. There was no relation between home dampness and case-control status after stratification for sensitization, however. Restriction of the analysis to cases with elevated serum IgE levels against dust mites and/or molds, and to controls without elevated serum IgE, increased the odds ratios, and several became significant at p < 0.05. This supports a connection between damp housing and sensitization to dust mites and/or molds and childhood respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

The exposure of cyclists, car drivers and pedestrians to traffic-related air pollutants.

Volunteers provided with personal air sampling (PAS) equipment covered concurrently, by car or bicycle, various selected routes. These comprised two inner city routes in Amsterdam (ICR 1 and 2) as well as a route including a tunnel on a busy highway (TR) and a rural route just south of Amsterdam (RR). A third inner city route, a busy narrow street, was subsequently also selected, and covered by bicycle or walking (ICR 3). Each run lasted about 1 h; the sampling time on the TR route was approximately 30 min. The sampling periods in January and May lasted 2 weeks with four sampling days per week. In August only ICR 3 was covered, this sampling period lasted 2 days. CO, NO2, benzene, toluene and xylenes were measured in the personal air samples. A monitoring vehicle covered the routes concurrently and measured CO, NO2 and pm10 (semi) continuously. Lead and PAH content in pm10 was determined. The ventilation of the volunteers was measured while they were using a car or a bicycle. The route and the type of transport influenced (P < 0.001) the concentrations of CO, benzene, toluene and xylenes. The daily average temperature was positively associated with the exposure of car drivers and cyclists to most compounds measured. A volunteer exhaled on average 2.3 times more air as a cyclist than as a car driver. Despite the much higher concentrations in the personal air samples of car drivers, the uptake of CO, benzene, toluene and xylenes of cyclists sometimes approached that of the car drivers. The uptake of NO2 of cyclists was clearly higher than that of car drivers.