ExpoFacts--an overview of European exposure factors data.

European exposure factor data have been collected in one centrally available, freely accessible site on the Internet: the ExpoFacts database (http://www.ktl.fi/expofacts/). The process of compiling the database required locating the exposure factor data and evaluating its general applicability and public availability. The scope of the ExpoFacts database covers 30 European countries, often each with its own approach for data generation and publication. The database includes information on food intake, time use, physiology, housing, and demographic parameters, as available. Information included in the database, as well as the challenges in collecting and compiling this information, are summarized. Data were found to be unavailable for ExpoFacts for a number of reasons: (1) data have not been collected, (2) collected data are not published, (3) the publishing format or language makes the data hard to locate and use, (4) copyright restrictions prevent presenting the data in an open access website, or (5) data exist, but are too expensive to acquire. Improving accessibility and harmonization of existing data would enhance the information base for exposure and risk assessments. In addition, the ExpoFacts project demonstrates a successful process for acquiring, storing, and sharing exposure factors data.

Reduction potential of urban PM2.5 mortality risk using modern ventilation systems in buildings.

UNLABELLED: Urban PM2.5 (particulate matter with aerodynamic diameter smaller than 2.5 microm) is associated with excess mortality and other health effects. Stationary sources are regulated and considerable effort is being put into developing low-pollution vehicles and environment-friendly transportation systems. While waiting for technological breakthroughs in emission controls, the current work assesses the exposure reductions achievable by a complementary means: efficient filtration of supply air in buildings. For this purpose infiltration factors for buildings of different ages are quantified using Exposures of Adult Urban Populations in Europe Study (EXPOLIS) measurements of indoor and outdoor concentrations in a population-based probability sample of residential and occupational buildings in Helsinki, Finland. These are entered as inputs into an evaluated simulation model to compare exposures in the current scenario with an alternative scenario, where the distribution of ambient PM2.5 infiltration factors in all residential and occupational buildings are assumed to be similar to the subset of existing occupational buildings using supply air filters. In the alternative scenario exposures to ambient PM2.5 were reduced by 27%. Compared with source controls, a significant additional benefit is that infiltration affects particles from all outdoor sources. The large fraction of time spent indoors makes the reduction larger than what probably can be achieved by local transport policies or other emission controls in the near future. PRACTICAL IMPLICATIONS: It has been suggested that indoor concentrations of ambient particles and the associated health risks can be reduced by using mechanical ventilation systems with supply air filtering in buildings. The current work quantifies the effects of these concentration reductions on population exposures using population-based data from Helsinki and an exposure model. The estimated exposure reductions suggest that correctly defined building codes may reduce annual premature mortality by hundreds in Finland and by tens of thousands in the developed world altogether.

Population sampling in European air pollution exposure study, EXPOLIS: comparisons between the cities and representativeness of the samples.

A personal air pollution exposure study, EXPOLIS, was accomplished in six European cities among 25- to 55-year-old citizens. In order to compare the exposure results and different microenvironmental concentrations between the cities it is crucial to know the extent and effects of the population bias that has developed in sampling procedure and the sociodemographic characteristics of each measured population sample. In each participating city a random Base sample of 2000 to 3000 individuals was drawn from the census and a Short Questionnaire (SQ) was mailed to them. Two subsamples of the Respondents of the mailed questionnaire were randomly drawn: Diary sample for 48-h time--microenvironment--activity diary and extensive exposure questionnaires, and Exposure sample for the same plus personal exposure and microenvironmental monitoring. Significant differences existed between the EXPOLIS cities in the population-sampling procedure. Population-sampling bias was evaluated by comparing the Respondents with the total city populations. The share of women and individuals with more than 14 years of education is higher among the Respondents than the overall population except in Athens. Men, younger (25-34 years old) and unmarried individuals were hardest to get to participate in the study at least in Helsinki. The two subsamples differ from Respondents in having more employed and higher- educated individuals. The largest sample bias occurred at the first and easiest step of responding to the mailed Short Screening Questionnaire, and not at the last and most demanding stage of participating in the exposure measurements. Exposure data from some of EXPOLIS cities can only be compared to other cities with caution considering their large population bias or different sample selections. However the selection bias is not necessarily a problem for analyses about predictors of personal exposures or analyses within a city.

Urban commuter exposure to particle matter and carbon monoxide inside an automobile.

In-vehicle exposures to different sizes of particles and carbon monoxide (CO) were determined while driving along a standardized route under a variety of traffic conditions in Kuopio, Finland during the 12-month period from January to December 1995. Arithmetic means of in-vehicle exposures during the morning rush hours were 5.7 parts per million (ppm) (geometric mean, GM = 3.1 ppm, geometric standard deviation, GSD = 1.7) for CO, 107 #/cm3 (GM = 75 #/cm3, GSD = 1.9) for fine particles (optical equivalent particle size range 0.3-1 micron) and 0.9 #/cm3 (GM = 0.6 #/cm3, GSD = 2.1) for coarse particles (optical equivalent particle size range 1-10 microns). Fine particles and CO behaved similarly in different weather and traffic conditions, while the behavior of coarse particles was usually different, and often opposite. The driving conditions that affected the passengers' exposures to CO and fine particles were the time of day (morning vs. afternoon) and average speed (decreasing). The meteorological parameters that affected the passengers' exposures to CO and fine particles were wind speed (decreasing) and relative humidity (increasing). Wind speed, relative humidity and driving speed all had opposite effects on the exposure levels to fine vs. coarse particles. Added exposures (due to commuting on top of the background levels) to CO and fine particles were considerably higher in the morning vs. the afternoon runs and also higher in the slower vs. the faster runs.

Fine particle (PM25) measurement methodology, quality assurance procedures, and pilot results of the EXPOLIS study.

EXPOLIS is a European multicenter (Athens, Basel, Grenoble, Helsinki, Milan, and Prague) air pollution exposure study. It is the first international, population-based, large-scale study, where personal exposures to PM2.5 aerosol particles (together with volatile organic compounds and carbon monoxide) are being monitored. EXPOLIS is performed in six different centers across Europe, the sampled aerosol concentrations vary greatly, and the microenvironmental samples are not collected with the same equipment as the personal samples. Therefore careful equipment selection, methods development and testing, and thorough quality assurance and quality control (QA & QC) procedures are essential for producing reliable and comparable PM2.5 data. This paper introduces the equipment, the laboratory test results, the pilot results, the standard operating procedures, and the QA & QC procedures of EXPOLIS. Test results show good comparability and repeatability between personal and microenvironmental monitors for PM2.5 at different concentration levels measured across Europe in EXPOLIS centers.

Personal NO2 exposures of preschool children in Helsinki.

Weekly personal NO2 exposures of 246 children aged 3-6 years were measured with Palmes tubes during 13 weeks in winter and spring in 1991. Measurements were made in eight day-care centers in the downtown and suburban areas of Helsinki, Finland. At the same time, inside and outside NO2 concentration of the day-care centers and the ambient air fixed site measurements were conducted. Palmes tubes were found to be applicable for NO2 exposure measurements of preschool children, but rather high sample losses could be expected. The geometric mean of personal NO2 exposure levels of 13-week period was 26.5 micrograms/m3 in the downtown and 17.5 micrograms/m3 in the suburban area. Gas stove and smoking at home increased significantly personal exposure to NO2. The weekly population NO2 exposure correlated rather poorly with the fixed site ambient air NO2 levels (R2 = 0.37), but much better with the NO2 levels inside and outside the day-care centers (R2 = 0.88 and 0.86). In the suburban and downtown groups the between children variations in the NO2 exposures were only 14% and 28% of the total variations, which were dominated by the within child variation. Stationary measurements at the ambient air fixed sites and inside and outside the day-care centers explained the variation in personal exposures of the children well during the spring, but not during the winter. A regression model, where data from outside day-care center measurements, fixed ambient air monitors, residential area and home characteristics (i.e., gas stove, smoking inside at home, type of dwelling) were included, explained 32% of the personal NO2 exposure variation in winter and 67% in spring. In the absence of personal exposure measurements, both stationary measurements and questionnaire information are useful in estimating variations in personal exposures.

Characterization of air quality problems in five Finnish indoor ice arenas.

The air quality in five Finnish ice arenas with different volumes, ventilation systems, and resurfacer power sources (propane, gasoline, electric) was monitored during a usual training evening and a standardized, simulated ice hockey game. The measurements included continuous recording of carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2) concentrations, and sampling and analysis of volatile organic compounds (VOCs). Emissions from the ice resurfacers with combustion engines caused indoor air quality problems in all ice arenas. The highest 1-hour average CO and NO2 concentrations ranged from 20 to 33 mg/m3 (17 to 29 ppm) and 270 to 7440 micrograms/m3 (0.14 to 3.96 ppm), respectively. The 3-hour total VOC concentrations ranged from 150 to 1200 micrograms/m3. The highest CO and VOC levels were measured in the arena in which a gasoline-fueled resurfacer was used. The highest NO2 levels were measured in small ice arenas with propane-fueled ice resurfacers and insufficient ventilation. In these arenas, the indoor NO2 levels were about 100 times the levels measured in ambient outdoor air, and the highest 1-hour concentrations were about 20 times the national and World Health Organization (WHO) health-based air quality guidelines. The air quality was fully acceptable only in the arena with an electric resurfacer. The present study showed that the air quality problems of indoor ice arenas may vary with the fuel type of resurfacer and the volume and ventilation of arena building. It also confirmed that there are severe air quality problems in Finnish ice arenas similar to those previously described in North America.

Environmental chemicals relevant for respiratory hypersensitivity: the indoor environment.

The allergenic constituents of non-industrial indoor environments are predominantly found in the biologic fraction. Several reports have related biological particles such as mites and their excreta, dander from pets and other furred animals, fungi and bacteria to allergic manifestations including respiratory hypersensitivity among the occupants of buildings. Also, bacterial cell-wall components and the spores of toxin-producing moulds may contribute to the induction of hypersensitivity, but the relevance for human health is not yet determined. The knowledge regarding hypersensitivity and asthmatic reactions after exposure to chemical agents is primarily based on data from occupational settings with much higher exposure levels than usually found in non-industrial indoor environments. However, there is evidence that indoor exposure to tobacco smoke, some volatile organic compounds (VOC) and various combustion products (either by using unvented stoves or from outdoor sources) can be related to asthmatic symptoms. In some susceptible individuals, the development of respiratory hypersensitivity or elicitation of asthmatic symptoms may also be related to the indiscriminate use of different household products followed by exposure to compounds such as diisocyanates, organic acid anhydrides, formaldehyde, styrene and hydroquinone. At present, the contribution of the indoor environment both to the development of respiratory hypersensitivity and for triggering asthmatic symptoms is far from elucidated.

Behavior of Chernobyl fallout radionuclides in peat combustion.

The fallout from the explosion and fire at the Chernobyl nuclear power plant concentrated levels of up to 10 kBq 137Cs kg-1 dry weight in the fuel peat harvested during the summer of 1986 in Finland. We investigated the behavior of fallout radionuclides 137Cs, 134Cs, 106Ru, 144Ce, 125Sb, 95Zr, and 110mAg together with naturally occurring 210Pb and 226Ra in the combustion of this contaminated peat in four different power plants. The elements antimony, ruthenium, lead, and cesium were enriched on the smallest particles, indicating that they were in a volatile chemical form, while cerium, zirconium, and radium were nonvolatile at the combustion temperatures. This result confirms the previous finding that ruthenium is volatile in combustion. Although metallic ruthenium requires 2,310 degrees C to melt, some of its oxides melt and evaporate at much lower temperatures.

Mutagenic compounds in wood-chip drying fumes.

The mutagenicity of fumes from the heating of freshly cut spruce and birch chips was measured with Salmonella typhimurium strains TA98, TA100 and TA102. The bacteria were exposed directly and indirectly to the fumes. Wood chips were also extracted with solvents. No mutagenicity was found in wood extracts or the fume samples measured indirectly. The results from the direct exposure experiments indicate, however, that drying spruce and birch at 170 degrees C emits mutagenic compounds, which are short-lived and/or volatile. One of the mutagenic compounds of the fumes is probably 3-carene. These results are consistent with previous epidemiological findings, which suggest that these fumes are carcinogenic.

Artificial radioactivity in fuel peat and peat ash in Finland after the Chernobyl accident.

The accident at the Chernobyl nuclear power plant in April 1986 caused very uneven deposition of radionuclides in Finland. The deposited radionuclides were found in relatively high concentrations in fuel peat and especially in peat ash because a thin surface layer of peat-production bogs was extracted as fuel peat soon after the fallout occurred. Concentrations of artificial radionuclides in fuel peat and peat ash were measured at six peat-fired power plants in Finland throughout the heating season 1986-87. Concentrations of 137Cs in composite peat samples varied between 30 and 3600 Bq kg-1 dry weight and in ash samples between 600 and 68,000 Bq kg-1. High concentrations in peat ash caused some restrictions to the utilization of peat ash for various purposes.

Bioaerosols and office building ventilation systems.

Becterial and fungal spore samples were collected from twelve office building ventilation systems. Measurements were done both with and without humidification. Ventilation or humidification systems were not found to act as bioaerosol sources in any case. No difference was observed between bioaerosol counts in offices with and without humidification. The microbial levels decreased in all ventilation systems.