Indoor gaseous air pollutants determinants in office buildings-The OFFICAIR project.

The aim of this study was to identify determinants of aldehyde and volatile organic compound (VOC) indoor air concentrations in a sample of more than 140 office rooms, in the framework of the European OFFICAIR research project. A large field campaign was performed, which included (a) the air sampling of aldehydes and VOCs in 37 newly built or recently retrofitted office buildings across 8 European countries in summer and winter and (b) the collection of information on building and offices' characteristics using checklists. Linear mixed models for repeated measurements were applied to identify the main factors affecting the measured concentrations of selected indoor air pollutants (IAPs). Several associations between aldehydes and VOCs concentrations and buildings' structural characteristic or occupants' activity patterns were identified. The aldehyde and VOC determinants in office buildings include building and furnishing materials, indoor climate characteristics (room temperature and relative humidity), the use of consumer products (eg, cleaning and personal care products, office equipment), as well as the presence of outdoor sources in the proximity of the buildings (ie, vehicular traffic). Results also showed that determinants of indoor air concentrations varied considerably among different type of pollutants.

Environmental data treatment to support exposure studies: The statistical behavior for NO2, O3, PM10 and PM2.5 air concentrations in Europe.

In determining and assessing external exposure, there is a need for extensive environmental data sets of sufficient time and space resolution. It is unlikely that a complete set of those data exist for a specific study. Therefore, there will be a need to fill the necessary data gaps. As a first step towards this direction, the statistical behavior of the parameters involved can be estimated so that such parameters can be statistically reconstructed in finer scales. In this study the methodology has been applied to the air concentrations of the priority pollutants NO2, O3, PM10 (particulate matter with an aerodynamic diameter of<10 µm) and PM2.5 (particulate matter with an aerodynamic diameter of<2.5 µm). More specifically, the hourly and the daily concentrations at a given site of those pollutants can be statistically reconstructed assuming known (a) the concentration annual average (m), (b) the pdf of the ratio of the standard deviation over the annual average (σ/m) for the hourly/daily concentrations and (c) the pdf for hourly/daily concentrations themselves. In the case that PM2.5 annual value is missing, it is estimated statistically from the PM10 annual value and the PM2.5/PM10 ratio statistics. As a first test, the proposed methodology is applied for the year 2012 arriving to concrete proposals concerning the statistical behavior of the above-mentioned parameters.

Investigation of the PM2.5, NO2 and O3 I/O ratios for office and school microenvironments.

Differentiation of the exposure to PM2.5 (particulate matter less than 2.5 µm in aerodynamic diameter), NO2 and O3 i.e. pollutants of outdoor origin, due to the occupation of office and school microenvironments, was investigated through the quantification of the respective Indoor to Outdoor (I/O) ratios, in simple statistical terms. For that cause, indoor and outdoor observation data were retrieved from the HEALS EDMS database, and more specifically the data from the OFFICAIR and the SINPHONIE EU projects. The I/O ratios were produced and were statistically analyzed in order to be able to study the influence of the indoor environment against the pollutants coming from outdoors. The present statistical approach highlighted also the differences of I/O ratios between the two studied microenvironments for each pollutant. For exposure estimation to the above-mentioned pollutants, the probability and cumulative distribution function (pdf/cdf) empirical approximations led to the conclusion that for offices the I/O ratios of PM2.5 follow a normal distribution, while NO2 and O3 a gamma distribution. Respectively, for schools the I/O ratios of all pollutants follow a lognormal distribution.

Spatial and temporal variation of particulate matter characteristics within office buildings - The OFFICAIR study.

In the frame of the OFFICAIR project, office buildings were investigated across Europe to assess how the office workers are exposed to different particulate matter (PM) characteristics (i.e. PM2.5 mass concentration, particulate oxidative potential (OP) based on ascorbate and reduced glutathione depletion, trace element concentration and total particle number concentration (PNC)) within the buildings. Two offices per building were investigated during the working hours (5 consecutive days; 8h per day) in two campaigns. Differences were observed for all parameters across the office buildings. Our results indicate that the monitoring of the PM2.5 mass concentration in different offices within a building might not reflect the spatial variation of the health relevant PM characteristics such as particulate OP or the concentration of certain trace elements (e.g., Cu, Fe), since larger differences were apparent within a building for these parameters compared to that obtained for the PM2.5 mass concentration in many cases. The temporal variation was larger for almost all PM characteristics (except for the concentration of Mn) than the spatial differences within the office buildings. These findings indicate that repeated or long-term monitoring campaigns are necessary to have information about the temporal variation of the PM characteristics. However, spatial variation in exposure levels within an office building may cause substantial differences in total exposure in the long term. We did not find strong associations between the investigated indoor activities such as printing or windows opening and the PNC values. This might be caused by the large number of factors affecting PNC indoors and outdoors.

Perceived Indoor Environment and Occupants' Comfort in European "Modern" Office Buildings: The OFFICAIR Study.

Indoor environmental conditions (thermal, noise, light, and indoor air quality) may affect workers' comfort, and consequently their health and well-being, as well as their productivity. This study aimed to assess the relations between perceived indoor environment and occupants' comfort, and to examine the modifying effects of both personal and building characteristics. Within the framework of the European project OFFICAIR, a questionnaire survey was administered to 7441 workers in 167 "modern" office buildings in eight European countries (Finland, France, Greece, Hungary, Italy, The Netherlands, Portugal, and Spain). Occupants assessed indoor environmental quality (IEQ) using both crude IEQ items (satisfaction with thermal comfort, noise, light, and indoor air quality), and detailed items related to indoor environmental parameters (e.g., too hot/cold temperature, humid/dry air, noise inside/outside, natural/artificial light, odor) of their office environment. Ordinal logistic regression analyses were performed to assess the relations between perceived IEQ and occupants' comfort. The highest association with occupants' overall comfort was found for "noise", followed by "air quality", "light" and "thermal" satisfaction. Analysis of detailed parameters revealed that "noise inside the buildings" was highly associated with occupants' overall comfort. "Layout of the offices" was the next parameter highly associated with overall comfort. The relations between IEQ and comfort differed by personal characteristics (gender, age, and the Effort Reward Imbalance index), and building characteristics (office type and building's location). Workplace design should take into account both occupant and the building characteristics in order to provide healthier and more comfortable conditions to their occupants.

Oxidative potential and chemical composition of PM2.5 in office buildings across Europe - The OFFICAIR study.

In the frame of the OFFICAIR project, indoor and outdoor PM2.5 samples were collected in office buildings across Europe in two sampling campaigns (summer and winter). The ability of the particles to deplete physiologically relevant antioxidants (ascorbic acid (AA), reduced glutathione (GSH)) in a synthetic respiratory tract lining fluid, i.e., oxidative potential (OP), was assessed. Furthermore, the link between particulate OP and the concentration of the PM constituents was investigated. The mean indoor PM2.5 mass concentration values were substantially lower than the related outdoor values with a mean indoor/outdoor PM2.5 mass concentration ratio of 0.62 and 0.61 for the summer and winter campaigns respectively. The OP of PM2.5 varied markedly across Europe with the highest outdoor OP(AA) m(-3) and OP(GSH) m(-3) (% antioxidant depletion/m(3) air) values obtained for Hungary, while PM2.5 collected in Finland exhibited the lowest values. Seasonal variation could be observed for both indoor and outdoor OP(AA) m(-3) and OP(GSH) m(-3) with higher mean values during winter. The indoor/outdoor OP(AA) m(-3) and OP(GSH) m(-3) ratios were less than one with 4 and 17 exceptions out of the 40 cases respectively. These results indicate that indoor air is generally less oxidatively challenging than outdoors. Correlation analysis revealed that trace elements play an important role in determining OP, in particular, the Cu content. Indoor air chemistry might affect OP since weaker correlations were obtained for indoor PM2.5. Our findings also suggest that office workers may be exposed to health relevant PM constituents to a different extent within the same building.