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The aim of this analysis is to study the association between air pollution and asthma among adults. For this goal, a previously developed "asthma score" was used.Persons aged 25-44 years were randomly selected (1991-1993) and followed up (2000-2002) within the European Community Respiratory Health Survey (ECRHS-I and II). The asthma score was defined from 0 to 5, based on positive answers to symptoms reported for the last 12 months: wheeze/breathlessness, chest tightness, dyspnoea at rest, dyspnoea after exercise, and woken by dyspnoea. Participants' home addresses were linked to outdoor modelled NO2 estimates for 2001. Negative binomial regression was used to model the asthma score.The score from ECRHS-II was positively associated with NO2 (Ratio of the Mean asthma Score (RMS) 1.23, 95% Confidence Intervals (CI): 1.09-1.38 for an increase of 10 microg.m(-3)). After excluding participants with asthma and symptoms at baseline, the association remained (RMS 1.25, 95%CI: 1.05-1.51) and was particularly high among those reporting a high score in ECRHS-II. The latter probably reflects incident cases of asthma.Our results suggest that traffic-related pollution causes asthma symptoms and possibly asthma incidence in adults. The asthma score offers an alternative to investigate the course and aetiology of asthma in adults.

Fine particulate matter (PM2.5) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM2.5 sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM2.5 analysed by ED-XRF. A total of 4-5 factors were identified at each site, three of them being common to all sites (interpreted as traffic. mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM2.5. Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM2.5 at the five sites (39-53% of PM2.5, 5.1-12.0 mu g m(-3)), while regional-scale secondary aerosols accounted for 14-34% of PM2.5 (2.6-4.5 mu g m(-3)), mineral matter for 13-31% (2.4-4.6 mu g m(-3)) and sea-salt made up 3-7% of the PM2.5 mass (0.4-1.3 mu g m(-3)). Consequently, despite regional and climatic variability throughout Spain, the same four main PM2.5 emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM2.5 as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM10. African dust inputs were observed in the mineral source, adding on average 4-11 mu g m(-3) to the PM2.5 daily mean during dust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2-8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl

The follow-up of cohorts of adults from more than 20 European centres of the former ECRHS I (1989-1992) investigates long-term effects of exposure to ambient air pollution on respiratory health, in particular asthma and change of pulmonary function. Since PM2.5 is not routinely monitored in Europe, we measured PM2.5 concentrations in 21 participating centres to estimate 'background' exposure in these cities. Winter (November-February), summer (May-August) and annual mean (all months) values of PM2.5 were determined from measuring periods between June 2000 and November 2001. Sampling was conducted for 7 days per month for a year. Annual and winter mean concentrations of PM2.5 vary substantially being lowest in Iceland and highest in centres in Northern Italy. Annual mean concentrations ranged from 3.7 to 44.9 mug m(-3), winter mean concentrations from 4.8 to 69.2 mug m(-3), and summer mean concentrations from 3.3 to 23.1 mugm(-3). Seasonal variability occurred but did not follow the same pattern across all centres. Therefore, ranking of centres varied from summer to winter. Simultaneously, NO2 concentrations were measured using passive sampling tubes. Annual mean NO2 concentrations range from 4.9 to 72.1 mug m(-3) with similar seasonal variations across centres and constant ranking of centres between seasons. The correlation between annual NO2 and PM2.5 concentrations is fair (Spearman correlation coefficient r(s) = 0.75), but when considered as monthly means the correlation is far less consistent and varies substantially between centres. The range of PM2.5 mass concentrations obtained in ECRHS II is larger than in other current cohort studies on long-term effects of air pollution. This substantial variation in PM2.5 exposure will improve statistical power in future multilevel health analyses and to some degree may compensate for the lack of information on within-city variability. Seasonal means may be used to indicate potential differences in the toxicity across the