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Indoor air quality was characterized in 10 recently built energy-efficient French schools during two periods of 4.5 days. Carbon dioxide time-resolved measurements during occupancy clearly highlight the key role of the ventilation rate (scheduled or occupancy indexed), especially in this type of building, which was tightly sealed and equipped with a dual-flow ventilation system to provide air refreshment. Volatile organic compounds ( VOCs) and inorganic gases (ozone and NO2) were measured indoors and outdoors by passive techniques during the occupied and the unoccupied periods. Over 150 VOC species were identified. Among them, 27 species were selected for quantification, based on their occurrence. High concentrations were found for acetone, 2-butanone, formaldehyde, toluene, and hexaldehyde. However, these concentrations are lower than those previously observed in conventional school buildings. The indoor/outdoor and unoccupied/occupied ratios are informative regarding emission sources. Except for benzene, ozone, and NO2, all the pollutants in these buildings have an indoor source. Occupancy is associated with increased levels of acetone, 2-butanone, pentanal, butyl acetate, and alkanes. [ABSTRACT FROM AUTHOR]

Abstract: Since 1990, the MERA (MEsure des Retombées Atmosphériques, French acronym for background air pollution monitoring) network has been focused on the composition of the lower troposphere within the EMEP program. In particular, 46 non-methane hydrocarbon (NMHC) concentrations have been measured between 1997 and 2006 at three MERA sites. The analysis of temporal trends using Mann-Kendall and Sen methods showed a global decrease of anthropogenic NMHC. These results are in accordance with the trends observed on other sites in Europe and follow the decrease of VOCs emissions in France. Nevertheless the concentrations of long-life species like ethane seem to remain steady showing the growing influence of most distant source areas. In addition isoprene concentrations are typically higher in France than in other countries in Europe and slightly rising. Data analysis was performed using positive matrix factorization (PMF). Five similar PMF factors are identified as aged profiles for the three sites. The examination of factor contributions made it possible to determine a hierarchy in source influence. A higher contribution of evaporative sources was observed on the southern site while residential heating was the main factor for the other two. This work was completed by a clustering analysis (K-means) of air mass trajectories in order to apportion source contribution depending on air mass origins. Two main groups have been distinguished: (1) older and diluted air masses from an oceanic origin; and (2) anthropogenic and closer sources indicating continental influence. [Copyright &y& Elsevier]

Environmental odor studies are usually done using two approaches: nuisance impact assessment and source identification. The latter may be done using chemical analysis or sensory analysis. While sensory analyses offer many advantages, they also face the main obstacle: odor nature description still uses conventional methods based on subjective evocations as odor descriptors. This makes the sensory method ineffective especially when the expected outcome is the source identification in the context of an industrial accident. This work wants to fulfill this gap proposing to build an objective database including the odor nature description of selected potentially emitted compounds using a promising approach: the Langage des Nez® (LdN). Using definite odorous compounds as odor referents, this work provides the odor nature description of 44 compounds, reported as potential incidentally released chemical compounds in the industrial zone of Le Havre. The city of Le Havre, France, was chosen as a model due to a history of odorous emissions of industrial origins. A trained panel described the odor of each compound using up to three referents of the LdN referents collection and attributed a score to each referent. A data analysis method was developed based on the frequency of citation of the referents and the attributed scores allowing the categorization of each compound in three types of consensus categories. The data analysis results showed that around 80% of compounds were described with a good consensus, showing the LdN as a well-adapted lexicon. This study does not point to any correlation between the chemical structures of the compounds of interest and their relative referents. When compared to conventional methods, LdN revealed a more objective and precise approach. The proposed experimental method and the results provided in this work offer the first insight for time-efficient approaches to objectively describe environmental odors, especially potentially emitted odors during incidents. This work may be supplemented by abatement and mixture effect investigations for a complete understanding of odor dispersion., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Two measurement campaigns of volatile organic compounds (VOC) were carried out in the industrial city of Dunkerque, using Radiello passive samplers during winter (16-23 January) and summer (6-13 June) 2007. 174 compounds were identified belonging to six chemical families. Classifying sampling sites with similar chemical profiles by hierarchical ascending classification resulted in 4 groups that reflected the influence of the main industrial and urban sources of pollution. Also, the BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) quantification allowed us to map their levels of concentration. Benzene and toluene (BT) showed high concentrations in Northern Dunkerque reflecting the influence of two industrial plants. Differences among spatial distributions of the BT concentrations over contrasted meteorological conditions were also observed. An atypical ratio of T/B in the summer samples led us to investigate the BTEX origins shedding light on the contribution of pollutants transported across various zones of VOC emissions situated in Europe.

The global objective of this two part study was (1) to conduct VOC measurements in order to further understand VOC behaviour in an urban area influenced by industrial emissions and (2) to evaluate the role of these specific sources relative to urban sources. In this first paper a thorough descriptive and qualitative analysis is performed. A second article will be devoted to the quantitative analysis using Chemical Mass Balance (CMB) modelling. In the Dunkerque (France) area most industrial sources are situated in the north and the west of the receptor site whereas urban and traffic sources are located in the south and the east. A data set constituted of nearly 330,000 VOC data has been developed from the hourly measurements of 53 VOCs for 1 year from September 2002 to August 2003. It also contains meteorological parameters such as temperature, wind direction and wind speed. Using different graphical methods, the influence of the different sources on the ambient VOC concentrations has been highlighted at different time scales. In this work, the analysis of daily time series for the 53 VOCs shows the influence of traffic exhaust emissions because of the increases at traffic rush hours. Besides, the seasonal evolution of the VOC/acetylene ratio points out the influence of evaporative sources on ambient VOC concentration. Concerning other point sources, the variations of measured VOC concentrations for different wind directions and scatter plots of VOC hourly concentrations highlight the influence of some industrial sources.

In Part I of this study (Badol C, Locoge N, Leonardis T, Gallo JC. Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions, Part I: Study area description, data set acquisition and qualitative data analysis of the data set. Sci Total Environ 2007; submitted as companion manuscript.) the study area, acquisition of the one-year data set and qualitative analysis of the data set have been described. In Part II a source profile has been established for each activity present in the study area: 6 profiles (urban heating, solvent use, natural gas leakage, biogenic emissions, gasoline evaporation and vehicle exhaust) have been extracted from literature to characterise urban sources, 7 industrial profiles have been established via canister sampling around industrial plants (hydrocarbon cracking, oil refinery, hydrocarbon storage, lubricant storage, lubricant refinery, surface treatment and metallurgy). The CMB model is briefly described and its implementation is discussed through the selection of source profiles and fitting species. Main results of CMB modellings for the Dunkerque area are presented. (1) The daily evolution of source contributions for the urban wind sector shows that the vehicle exhaust source contribution varies between 40 and 55% and its relative increase at traffic rush hours is hardly perceptible. (2) The relative contribution of vehicle exhaust varies from 55% in winter down to 30% in summer. This decrease is due to the increase of the relative contribution of hydrocarbon storage source reaching up to 20% in summer. (3) The evolution of source contributions with wind directions has confirmed that in urban wind sectors the contribution of vehicle exhaust dominate with around 45-55%. For the other wind sectors that include some industrial plants, the contribution of industrial sources is around 60% and could reach 80% for the sector 280-310 degrees , which corresponds to the most dense industrial area. (4) The pollution in Dunkerque has been globally characterised taking into account the frequency of wind directions and contributions of sources in each wind direction for the whole year. It has been concluded that contribution of industrial sources is below 20% whereas vehicle exhaust contribution is superior to 40%.

Fifty non-methane hydrocarbons (NMHC) and seventeen carbonyl compounds were measured at a French rural site from 1997 to 2001, as part of the EMEP programme. Data handling was based on an original source-receptor approach. First, the examination of the levels and trends was completed by the comparison of the seasonal distribution of rural and urban VOC/acetylene ambient ratios. This analysis has shown that most of the compounds derived from mixing and photochemical transformation of mid-range transported urban pollutants from the downwind urban area. Then, identified sources and sinks were temporally apportioned. Urban air masses mixing explains, at least, 80% of the wintertime levels of anthropogenic NMHC and isoprene. In summer, photochemistry dominates the day-to-day distribution of anthropogenic NMHC whilst summertime isoprene is also controlled by in-situ biogenic emissions. Then, the results of C(1)-C(3) carbonyls were discussed with respect to their direct biogenic and anthropogenic emissions and photochemical production through the [carbonyl/auto-exhaust tracers] emission ratio. Diluted vehicle exhaust emissions mainly contribute to the total content of lower aldehydes in winter while other processes control lower ketones. Secondary production is predominant in summer with at least a 50% high intensity. Its dependence upon temperature and radiation is also demonstrated. Finally, the importance of the primary and secondary biogenic production of acetone and formaldehyde is assessed. In particular, biogenic contribution would explain 37 +/- 25% of acetone levels in summer.