We found sizeable acute health effects of fine and ultrafine particles. Although differential reliability in exposure assessment, in particular of ultrafine particles, precludes a firm conclusion, the study indicates that particulate matter of different sizes tends to have diverse outcomes, with dissimilar latency between exposure and health response.

In this study, long-term aerosol particle total number concentration measurements in five metropolitan areas across Europe are presented. The measurements have been carried out in Augsburg, Barcelona, Helsinki, Rome, and Stockholm using the same instrument, a condensation particle counter (TSI model 3022). The results show that in all of the studied cities, the winter concentrations are higher than the summer concentrations. In Helsinki and in Stockholm, winter concentrations are higher by a factor of two and in Augsburg almost by a factor of three compared with summer months. The winter maximum of the monthly average concentrations in these cities is between 10,000 cm Ϫ3 and 20,000 cm Ϫ3 , whereas the summer min is ϳ5000 -6000 cm Ϫ3 . In Rome and in Barcelona, the winters are more polluted compared with summers by as much as a factor of 4 -10. The winter maximum in both Rome and Barcelona is close to 100,000 cm Ϫ3 , whereas IMPLICATIONSThis manuscript gives an overview of aerosol particle number concentrations in five European cities over about a two-year period. These data are valuable for: (1) providing basic information about fine and ultrafine particulate pollution concentrations in European cities; (2) showing the diurnal and annual variation of the aerosol concentrations; (3) providing data for future legislation concerning the particulate pollution; and (4) giving a database that can be used in epidemiological studies related to aerosol particles and health effects.

No abstract

Background: A smoking ban in all indoor public places was enforced in Italy on 10 January 2005. Methods: We compared indoor air quality before and after the smoking ban by monitoring the indoor concentrations of fine (,2.5 mm diameter, PM 2.5 ) and ultrafine particulate matter (,0.1 mm diameter, UFP). PM 2.5 and ultrafine particles were measured in 40 public places (14 bars, six fast food restaurants, eight restaurants, six game rooms, six pubs) in Rome, before and after the introduction of the law banning smoking (after 3 and 12 months). Measurements were taken using real time particle monitors (DustTRAK Mod. 8520 TSI; Ultra-fine Particles Counter-TRAK Model 8525 TSI). The PM 2.5 data were scaled using a correction equation derived from a comparison with the reference method (gravimetric measurement). The study was completed by measuring urinary cotinine, and pre-law and post-law enforcement among non-smoking employees at these establishments Results: In the post-law period, PM 2.5 decreased significantly from a mean concentration of 119.3 mg/m 3 to 38.2 mg/m 3 after 3 months (p,0.005), and then to 43.3 mg/m 3 a year later (p,0.01). The UFP concentrations also decreased significantly from 76 956 particles/cm 3 to 38 079 particles/cm 3 (p,0.0001) and then to 51 692 particles/cm 3 (p,0.01). Similarly, the concentration of urinary cotinine among nonsmoking workers decreased from 17.8 ng/ml to 5.5 ng/ml (p,0.0001) and then to 3.7 ng/ml (p,0.0001). Conclusion: The application of the smoking ban led to a considerable reduction in the exposure to indoor fine and ultrafine particles in hospitality venues, confirmed by a contemporaneous reduction of urinary cotinine.

We found weak evidence of an association between daily ultrafine particles and mortality. Further studies are required with standardized protocols for ultrafine particle data collection in multiple European cities over extended study periods.

No abstract

Epidemiologists have observed higher risks for exposure to ambient particulate matter (PM) in the summer than in other seasons. This increased risk may be partly due to seasonal behaviour and higher exposures to indoor PM in the summer in relation to outdoor pollutant levels during winter when windows are kept closed and less time is spent outdoors. In this report, we analyse data from six European studies, based on three different methods of estimating outdoor to indoor infiltration factors, with the aim of characterizing the geographical and seasonal patterns of PM infiltration. The highest infiltration levels were observed for the summer in both a European combined dataset consisting of 382 observations of the average PM 2.5 infiltration factor for 1 day to 2weeks in regional data sets for Northern, Central and Southern Europe as well as for all ten cities individually. Th lowest values were observed for the winter, with spring and autumn displaying intermediate values. In all datasets and cities, the variability between residences and days within each season was much higher than the seasonal trend. PM 10 data were available from two studies, revealing that the PM 10 infiltration factors ranged from 70 to 92% of the corresponding PM 2.5 values. Some differences between the studies may be associated with the study designs and applied methods of determining the infiltration factor. The ratio of summer to winter PM 2.5 infiltration ranged from 1.3 in Rome to 2.3 in Helsinki, and the corresponding regional ratio ranged from 1.5 in Central Europe to 1.8 in Northern and Southern Europe. It is suggested that similar differences can be expected in epidemiological concentration-response relationships due to the modification in seasonal exposure associated with buildings and time spent indoors.

Objectives Few studies have assessed the effects of policies aimed to reduce traffic-related air pollution. The aims of this study were to evaluate the impact, in terms of air quality and health effects, of two low-emission zones established in Rome in the period 2001e2005 and to assess the impact by socioeconomic position (SEP) of the population. Methods We evaluated the effects of the intervention on various stages in the full-chain model, that is, pressure (number and age distribution of cars), emissions, PM 10 and NO 2 concentrations, population exposure and years of life gained (YLG). The impact was evaluated according to a small-area indicator of SEP. Results During the period 2001e2005, there was a decrease in the total number of cars (À3.8%), NO 2 and PM 10 emissions and concentrations (from 22.9 to 17.4 mg/m 3 for NO 2 and from 7.8 to 6.2 mg/m 3 for PM 10 ), and in the residents' exposure. In the two lowemission zones, there was an additional decrease in air pollution concentrations (NO 2 : À4.13 and À2.99 mg/m 3 ; PM 10 : À0.70 and À0.47 mg/m 3