Dikaia E. Saraga

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.

Assessment of indoor air quality in office buildings across Europe : the OFFICAIR study

The European project OFFICAIR aimed to broaden the existing knowledge regarding indoor air quality (IAQ) in modern office buildings, i.e., recently built or refurbished buildings. Thirty-seven office buildings participated in the summer campaign (2012), and thirty-five participated in the winter campaign (2012-2013). Four rooms were investigated per building. The target pollutants were twelve volatile organic compounds, seven aldehydes, ozone, nitrogen dioxide and particulate matter with aerodynamic diameter <2.5μm (PM2.5). Compared to other studies in office buildings, the benzene, toluene, ethylbenzene, and xylene concentrations were lower in OFFICAIR buildings, while the α-pinene and d-limonene concentrations were higher, and the aldehyde, nitrogen dioxide and PM2.5 concentrations were of the same order of magnitude. When comparing summer and winter, significantly higher concentrations were measured in summer for formaldehyde and ozone, and in winter for benzene, α-pinene, d-limonene, and nitrogen dioxide. The terpene and 2-ethylhexanol concentrations showed heterogeneity within buildings regardless of the season. Considering the average of the summer and winter concentrations, the acetaldehyde and hexanal concentrations tended to increase by 4-5% on average with every floor level increase, and the nitrogen dioxide concentration tended to decrease by 3% on average with every floor level increase. A preliminary evaluation of IAQ in terms of potential irritative and respiratory health effects was performed. The 5-day median and maximum indoor air concentrations of formaldehyde and ozone did not exceed their respective WHO air quality guidelines, and those of acrolein, α-pinene, and d-limonene were lower than their estimated thresholds for irritative and respiratory effects. PM2.5 indoor concentrations were higher than the 24-h and annual WHO ambient air quality guidelines.

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.

Chemical characterization of particulate matter (PM) and source apportionment study during winter and summer period for the city of Kozani, Greece

Eordaia basin located in northwest of Greece, comprises an area which is characterized by intense energy related activities, including coal burning at four power plants and the associated mining operations. Air samples of inhalable (PM10) and respirable particles (PM2.5) were collected in cold and warm periods in 2010 at an urban background site of Kozani, the major city and capital of the region which is located close to the power plants. Particulate matter concentration, particle-bound polycyclic aromatic hydrocarbons and anionic species concentrations were determined using gravimetric, GC-MS in SIM mode and Ion Chromatography analysis, respectively. For the cold period, the mean PM10 and PM2.5 mass concentration was found to be 19.62 and 14.68 µg m−3, respectively. Correspondingly, for the warm period, the mean PM10 and PM2.5 values were 35.29 and 25.75 µg m−3, respectively. In general, the results indicated that the major sources of air pollution in Kozani are traffic, combustion from agricultural activities and lignite power plants emissions, contributing by different percentages to each particle fraction.

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.

An investigation of the parameters influencing the determination of the number of particulate matter sources and their contribution to the air quality of an indoor residential environment

Indoor air quality depends on the presence of both indoor and outdoor particle sources each of which produces different particles’ size distribution that may have mortality and morbidity effects. Positive Matrix Factorization (PMF) is a mathematical (statistical) procedure for identifying and quantifying the sources of air pollutants at a receptor location. A critical step in PMF is the number of factors determination and the present study aims at discussing this critical issue, by applying PMF on particles size distribution measurements data in a residential environment, in Athens, Greece. A main focal point of the present research is the investigation of the temporal behaviour of the particles size, as recorded in the time series, closely relating the averaging period of the utilised data with the number and type of factors in the PMF. The analysis is based on the estimation of the spectral properties of data and estimation of the integral time scale using the autocorrelation properties of the series. Furthermore, different factor analysis techniques have been applied, namely the rotated Principle Component Analysis (rPCA) and the Independent Component Analysis (ICA) and the results have been compared to PMF results.

Contribution From Smoking To PM2.5, PM1Particles And VOCs Concentrations InResidential Houses In Athens, Greece

The objective of this study was to investigate the indoor and outdoor air quality at two residences in a suburban area of Athens, based on different human activities (smoking and non-smoking, open and closed windows). For this purpose, two apartments in the same area were equipped with particulate matter samplers with PM1 and PM2.5 impactors and VOCs samplers for benzene, toluene, m,p-xylene, o-xylene measurements. Both apartments had 4 inhabitants, while one smoker was living in the second one, smoking on average 10 cigarettes per day. Daily activities were also recorded to questionnaires. The results indicated that for the non-smokers apartment, the main source of PM2.5 indoor concentration seems to be PM2.5 outdoor concentration, while PM1 and VOCs concentrations followed a corresponding variation. On the other hand, the main source of indoor pollution in the smoker’s apartment seems to be smoking since PM2.5, PM1 and benzene indoor concentrations were found 2.5, 3.5 and 1.4 times higher than the ones observed in the non-smokers house. In addition, during two days of smoker’s absence, PM2.5, PM1 and VOCs indoor concentrations were decreased but still over the outdoor concentrations.

PM2.5 source apportionment for the port city of Thessaloniki, Greece

This paper aims to identify the chemical fingerprints of potential PM2.5 sources and estimate their contribution to Thessaloniki port-citys air quality. For this scope, Positive Matrix Factorization model was applied on a comprehensive PM2.5 dataset collected over a one-year period, at two sampling sites: the port and the city center. The model indicated six and five (groups of) sources contributing to particle concentration at the two sites, respectively. Traffic and biomass burning (winter months) comprise the major local PM sources for Thessaloniki (their combined contribution can exceed 70%), revealing two of the major control-demanding problems of the city. Shipping and in-port emissions have a non-negligible impact (average contribution to PM2.5: 9-13%) on both primary and secondary particles. Road dust factor presents different profile and contribution at the two sites (19.7% at the port; 7.4% at the city center). The secondary-particle factor represents not only the aerosol transportation over relatively long distances, but also a part of traffic-related pollution (14% at the port; 34% at the city center). The study aims to contribute to the principal role of quantitative information on emission sources (source apportionment) in port-cities for the implementation of the air quality directives and guidelines for public health.