Air quality in cabin environment of different passenger cars: effect of car usage, fuel type and ventilation/infiltration conditions.

Despite that commuters spend only 5.5% of their time in cabin vehicles, their exposure to harmful air pollutants, originated from the vehicle itself, and traffic emission is considered significant. In this study, two passenger cars with different type of fuels were investigated in terms of air quality and thermal comfort of their cabin. Investigation was performed in the city of Kozani, Northern Greece. Moreover, air samples near the exhausts were taken, in order to compare concentration of compounds found indoors. Twelve volatile organic compounds and CO2 were measured inside the cabin when the cars were stopped, when idle and when they were cruising in medium and heavy traffic roads, under various ventilated conditions. Thermal comfort was investigated while driving the cars through the city traffic. Results showed that the air around the diesel exhaust is less affected by emissions from the engine compared to LPG fuel. This is reflected to the TVOC measured into the cabin. Results also revealed that the air quality of a diesel fuel moving car with open windows is only affected by the traffic emissions from neighbouring vehicles, while for the car with LPG fuel, the self-pollution from its own exhaust might contribute together with the outdoor air.

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.

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-city's 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.

A comprehensive air quality investigation at an aquatic centre: Indoor/outdoor comparisons.

Air quality and comfort parameters in a naturally ventilated aquatic centre were studied in relation to the outdoor pollution levels. Simultaneous measurements of PM 2.5, as well as of volatile organic compounds, were carried out for the indoor and outdoor environment of the aquatic centre. The chemical analysis of ionic species and trace elements associated with particulate matter was also performed. In addition, automated analyzer for NO2 and O3 was used in order to record the indoor and outdoor levels of these pollutants. Analysis of diurnal variation of the pollutants' concentration was applied to the collected data, allowing the identification of potential variation on the sources affecting the indoor air quality. PM 2.5 concentration was almost two times higher indoors than outdoors with average values of 13.96 and 6.78 µg/m3, respectively. Concerning the ion fraction of PM 2.5, SO42- and Ca2+ were the ions with higher concentration indoors with values of 1.06 and 0.93 µg/m3, respectively, while the percentage of Cl- to the PM 2.5 fraction of the indoor atmosphere (9%) was too high than outdoor ones (1%). These results showed that indoor air of swimming pool concerning PM 2.5 and ionic species is mainly affected by the chlorination process along with the comfort conditions (high relative humidity) created during the operation of the facility. The common volatile organic compound concentrations at indoor air are generally in higher levels, compared to the outdoor air with p,m-xylene and toluene to be the substances with the higher concentration for indoor and outdoor area, respectively (7.80 and 1.57 µg/m3); nevertheless, values were rather low compared with the findings of other studies. Also, they clearly demonstrate a diurnal variation as a result of poor ventilation during night. As it was expected, chloroform showed the highest concentration compared to the other volatile organic compounds with values ranging from 3.35 to 135.89 µg/m3, with an average of 54.50 µg/m3. Concerning the NO2 concentration, indoor levels showed an increased pattern when the swimming pool was fully occupied, a fact that reveals a possible correlation. As an overall conclusion, the natural ventilation and the disinfection process seem to play a key role to the air quality of the indoor air of the aquatic centre.

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.

One-year intensive characterization on PM2.5 nearby port area of Thessaloniki, Greece.

The chemical characterization of particulate matter (PM) 2.5 fraction was studied during a 1-year sampling campaign conducted at a site near Thessaloniki's port area. PM2.5 collected samples were chemically analyzed for polycyclic aromatic hydrocarbons, minerals, and trace elements (Pb, Ni, Cu, V, Mn, Cr, Zn, Mg, K, Ti, Fe, Ca, and Al); water-soluble ions (Cl(-), NO3 (-), SO4 (2-), K(+), Na(+), NH4 (+), Mg(2+), Ca(2+)); and organic and elemental carbon. The average annual PM2.5 concentration (66.0 µg/m(3)) was at the highest level compared with other studies reported for the same city but different sampling sites. The average daily sum of the measured concentration of polycyclic aromatic hydrocarbons (PAHs) was 12.76 ng/m(3); this value decreased to 6.73 ng/m(3) for the warm period and reached the value of 19.8 ng/m(3) for the cold period. The average concentration of benzo[a]pyrene during the sampling period was 0.75 ng/m(3), which is below the European Union limit value of 1.0 ng/m(3). The ionic content comprised, on average, 22.6 % of the PM2.5 mass, with sulfate and ammonium being the most abundant species (31 and 26 %, respectively, of measured ions during the whole sampling period). The annual mean concentrations of organic carbon (OC) and elemental carbon (EC) were 10.5 ± 6.3 and 2.3 ± 1.5 µg/m(3), respectively. The OC/EC ratio ranged from 1.6 to 9.9, suggesting that there is a significant influence of residential wood burning for heating as well as ship and vehicle emissions to the sampling area. Finally, the elemental composition of associated PM2.5 was dominated by Ca, Fe, and Al. Although conclusions based only on PM2.5 measurements cannot entirely estimate all harbor sources' contribution, there is evidence to support that port activities affect the city's air quality and vice versa.

Modeling Short-Term Maximum Individual Exposure from Airborne Hazardous Releases in Urban Environments. Part I: Validation of a Deterministic Model with Field Experimental Data.

The release of airborne hazardous substances in the atmosphere has a direct effect on human health as, during the inhalation, an amount of concentration is inserted through the respiratory system into the human body, which can cause serious or even irreparable damage in health. One of the key problems in such cases is the prediction of the maximum individual exposure. Current state of the art methods, which are based on the concentration cumulative distribution function and require the knowledge of the concentration variance and the intermittency factor, have limitations. Recently, authors proposed a deterministic approach relating maximum individual exposure to parameters such as the fluctuation intensity and the concentration integral time scale. The purpose of the first part of this study is to validate the deterministic approach with the extensive dataset of the MUST (Mock Urban Setting Test) field experiment. This dataset includes 81 trials, which practically cover various atmospheric conditions and stability classes and contains in total 4004 non-zero concentration sensor data with time resolutions of 0.01-0.02 s. The results strengthen the usefulness of the deterministic model in predicting short-term maximum individual exposure. Another important output is the estimation of the methodology uncertainty involved.

Modelling Short-Term Maximum Individual Exposure from Airborne Hazardous Releases in Urban Environments. Part ΙI: Validation of a Deterministic Model with Wind Tunnel Experimental Data.

The capability to predict short-term maximum individual exposure is very important for several applications including, for example, deliberate/accidental release of hazardous substances, odour fluctuations or material flammability level exceedance. Recently, authors have proposed a simple approach relating maximum individual exposure to parameters such as the fluctuation intensity and the concentration integral time scale. In the first part of this study (Part I), the methodology was validated against field measurements, which are governed by the natural variability of atmospheric boundary conditions. In Part II of this study, an in-depth validation of the approach is performed using reference data recorded under truly stationary and well documented flow conditions. For this reason, a boundary-layer wind-tunnel experiment was used. The experimental dataset includes 196 time-resolved concentration measurements which detect the dispersion from a continuous point source within an urban model of semi-idealized complexity. The data analysis allowed the improvement of an important model parameter. The model performed very well in predicting the maximum individual exposure, presenting a factor of two of observations equal to 95%. For large time intervals, an exponential correction term has been introduced in the model based on the experimental observations. The new model is capable of predicting all time intervals giving an overall factor of two of observations equal to 100%.

PM1 and PM2.5 ionic composition and VOCs measurements in two typical apartments in Athens, Greece: investigation of smoking contribution to indoor air concentrations.

During the last decades, the air quality of the city of Athens has been quite aggravated. Scientific interest has been focused on health effects caused by both outdoor and indoor air pollution. The purpose of this study was the presentation of results from air quality measurements in two similar typical Athenian apartments in the same suburban area. In addition, smoking contribution is investigated, as it is the main factor which differentiates the two apartments. The results showed that it is the outdoor environment that mainly contributes to the air quality of the non-smokers' house. In the second apartment, PM2.5, PM1, and benzene concentrations were found significantly higher due to smoking activity. In contrast, no clear difference in particulate matter ionic composition between the two areas was observed, although in the smoker's house, ion concentrations were found elevated. This observation amplifies the assumption that in the smoker's apartment, significant outdoor sources' contribution cannot be excluded.