Atmosphere

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17 pages, 1169 KiB

Open AccessArticle

Are Grimmia Mosses Good Biomonitors for Urban Atmospheric Metallic Pollution? Preliminary Evidence from a French Case Study on Cadmium

by Bartholomé Vieille, Isabelle Albert, Sébastien Leblond, Florian Couvidat, Éric Parent and Caroline Meyer

Atmosphere 2021, 12(4), 491; https://doi.org/10.3390/atmos12040491 - 14 Apr 2021

Cited by 5 | Viewed by 2329

Abstract

Assessment of human exposure to atmospheric metals is a challenge, and mosses seem to be good biomonitors to help this purpose. Lacking roots, they are easy to collect and analyze. However, to our knowledge, no formal comparison was made between cadmium (Cd) measurements [...] Read more.

Assessment of human exposure to atmospheric metals is a challenge, and mosses seem to be good biomonitors to help this purpose. Lacking roots, they are easy to collect and analyze. However, to our knowledge, no formal comparison was made between cadmium (Cd) measurements in Grimmia mosses and alternative forecasts of atmospheric Cd pollution as those produced by the CHIMERE chemistry transport model. This work aims at studying this link to improve further biomonitoring. We compare 128 Cd measurements in the cemetery mosses of Paris and Lyon metropolitan areas (France) to CHIMERE Cd atmospheric forecasts. The area to consider around the cemetery for the CHIMERE forecasts has been defined by Kendall rank correlations between both information sources—Cd in mosses and CHIMERE Cd forecasts—from different area sizes. Then, we fit linear models to those two data sets including step-by-step different sources of uncertainty. Finally, we calculate moss predictions to compare predictions and measurements in the two cities. The results show an apparent link between the Cd concentrations in mosses and CHIMERE Cd forecasts including in addition the same unique covariate, the moss support (grave or wall), in the two cities. However, this model cannot be directly transposed from region to region because the strength of the link appears to be regional. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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14 pages, 4549 KiB

Open AccessArticle

Temporal Distribution and Gas/Particle Partitioning of Polycyclic Aromatic Hydrocarbons (PAHs) in the Atmosphere of Strasbourg, France

by Supansa Chimjarn, Olivier Delhomme and Maurice Millet

Atmosphere 2021, 12(3), 337; https://doi.org/10.3390/atmos12030337 - 5 Mar 2021

Cited by 17 | Viewed by 3112

Abstract

Gas and particulate phase ambient air concentrations of polycyclic aromatic hydrocarbons (Ʃ₁₆PAHs) were determined in Strasbourg, a large city located in the Alsace region of northeastern France, from May 2018 to March 2020, to study the evolution of their temporal variations [...] Read more.

Gas and particulate phase ambient air concentrations of polycyclic aromatic hydrocarbons (Ʃ₁₆PAHs) were determined in Strasbourg, a large city located in the Alsace region of northeastern France, from May 2018 to March 2020, to study the evolution of their temporal variations and their potential origins. The analysis of PAHs was performed using a global analytical method permitting the quantification of pesticides, PAHs, and polychlorobiphenyls (PCBs). Filters and Carbon doped silicon carbide NMC@SiC foams were extracted by accelerated solvent extraction (ASE) followed by a solid-phase extraction (SPE). Afterwards, extracts were analyzed using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Prior to analysis, a pre-concentration step based on solid-phase microextraction (SPME) was used with a polydimethylsiloxane (PDMS) 100 µm fiber. The average total (gas plus particulate) concentration of Ʃ₁₆PAHs varied from 0.51 to 117.31 ng m⁻³ with a mean of 16.87 ng m⁻³, with higher concentrations in the cold season of more than 2.5-fold and 6-fold that in the warm season for the gas and particulate phases, respectively. Moreover, low molecular weight (LMW) (2-ring and 3-ring) and medium molecular weight (MMW) (4-ring) PAHs contribute dominantly to the gas phase, while the particulate phase is associated with MMW (4-ring) and high molecular weight (HMW) (5-ring and 6-ring) PAHs. Gas/particle partitioning coefficient (log Kp) was calculated, and values varied between −4.13 and −1.49. It can be seen that the log Kp increased with the molecular weight of the PAHs and that the log Kp is different between cold and warm seasons for HMW PAHs but not for LMW PAHs. Diagnostic ratios of PAHs, which were employed to estimate the primary source of PAHs in Strasbourg, indicate that fuel combustion and biomass/coal burning are the possible origins of PAHs in Strasbourg’s atmosphere. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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19 pages, 1708 KiB

Open AccessArticle

PM₁₀ Chemical Profile during North African Dust Episodes over French West Indies

by Philippe Quénel, Jade Vadel, Céline Garbin, Séverine Durand, Olivier Favez, Alexandre Albinet, Christina Raghoumandan, Stéphanie Guyomard, Laurent Yves Alleman and Fabien Mercier

Atmosphere 2021, 12(2), 277; https://doi.org/10.3390/atmos12020277 - 19 Feb 2021

Cited by 1 | Viewed by 3048

Abstract

The French West Indies are periodically affected by North African dust episodes (NADE) resulting in PM₁₀ concentrations exceeding air quality standards. The aim of the present study was to decipher the PM₁₀ chemical profile during NADE over Guadeloupe. PM₁₀ samples [...] Read more.

The French West Indies are periodically affected by North African dust episodes (NADE) resulting in PM₁₀ concentrations exceeding air quality standards. The aim of the present study was to decipher the PM₁₀ chemical profile during NADE over Guadeloupe. PM₁₀ samples were collected daily at a rural site and an urban site during five episodes between April and October in 2017. During these events, the median PM₁₀ mass concentrations were, on average, 2 to 5 times higher than in the post-episode baseline period. Sampled filters were analyzed for their quantification of chemical constituents including carbonaceous fractions (elemental and organic carbon, EC/OC), anions/cations and levoglucosan, 51 elements, and 57 selected organic species. An orthogonal partial least squares discriminant analysis (OPLS-DA) was conducted to identify the specific chemical profile of PM₁₀ during NADE: 16 elements were identified as the most discriminant between the NADE and the control samples with mass concentration levels twice as high during a NADE. Among them, only two (Mn and V) are classified as emerging pollutant while no limit values exist for the other ones. The extensive characterization of the NADE PM₁₀ chemical profile we performed is a key step to assess the chemical exposure of French West Indies populations during such events. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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16 pages, 4076 KiB

Open AccessArticle

Retrospective Modeling of NO₂ and PM₁₀ Concentrations over the Lyon Metropolitan Area (France), 1990–2010—Performance Evaluation, Exposure Assessment and Correlation between Pollutants

by Thomas Coudon, Chi Vuong Nguyen, Perrine Volta, Lény Grassot, Florian Couvidat, Lionel Soulhac, John Gulliver, Francesca Romana Mancini, Béatrice Fervers and Pietro Salizzoni

Atmosphere 2021, 12(2), 239; https://doi.org/10.3390/atmos12020239 - 10 Feb 2021

Cited by 5 | Viewed by 2973

Abstract

Numerous cancers develop years after subjects have been exposed to chemical compounds. Thus, environmental epidemiological studies need to accurately reconstruct exposures over long periods. To estimate exposure to NO₂ and PM₁₀ concentrations, we modelled ground-level air concentrations, at very fine temporal [...] Read more.

Numerous cancers develop years after subjects have been exposed to chemical compounds. Thus, environmental epidemiological studies need to accurately reconstruct exposures over long periods. To estimate exposure to NO₂ and PM₁₀ concentrations, we modelled ground-level air concentrations, at very fine temporal (1 h) and spatial (10 m) resolutions, over a large European metropolitan area and at subject’s address of a French national cohort, for five different years (1990, 1995, 2000, 2005 and 2010). Model performances were assessed by comparing the annual modelled concentration against monitoring station measurements. As input data, we used background concentrations from a large-scale dispersion model. The relevance of our approach was assessed by comparing results in 2010, with a modelling using monitoring values as background data. The comparison with measurement data showed good performance of the model for the majority of the period, with a performance declined in 1990. Concentrations at the subject’s residence decreased by 45% for PM₁₀ and 38% for NO₂. The proportion of subjects exposed above the WHO recommendations declined from 100% to 50% for PM₁₀ and from 79% to 16% for NO₂. The results of this study would provide a reference for future models to assess chronic exposures to PM₁₀ and NO₂ on a larger scale. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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43 pages, 10413 KiB

Open AccessArticle

Overview of the French Operational Network for In Situ Observation of PM Chemical Composition and Sources in Urban Environments (CARA Program)

by Olivier Favez, Samuël Weber, Jean-Eudes Petit, Laurent Y. Alleman, Alexandre Albinet, Véronique Riffault, Benjamin Chazeau, Tanguy Amodeo, Dalia Salameh, Yunjiang Zhang, Deepchandra Srivastava, Abdoulaye Samaké, Robin Aujay-Plouzeau, Arnaud Papin, Nicolas Bonnaire, Carole Boullanger, Mélodie Chatain, Florie Chevrier, Anaïs Detournay, Marta Dominik-Sègue, Raphaële Falhun, Céline Garbin, Véronique Ghersi, Guillaume Grignion, Gilles Levigoureux, Sabrina Pontet, Jérôme Rangognio, Shouwen Zhang, Jean-Luc Besombes, Sébastien Conil, Gaëlle Uzu, Joël Savarino, Nicolas Marchand, Valérie Gros, Caroline Marchand, Jean-Luc Jaffrezo and Eva Leoz-Garziandia Show full author list Hide full author list

Atmosphere 2021, 12(2), 207; https://doi.org/10.3390/atmos12020207 - 3 Feb 2021

Cited by 29 | Viewed by 6591

Abstract

The CARA program has been running since 2008 by the French reference laboratory for air quality monitoring (LCSQA) and the regional monitoring networks, to gain better knowledge—at a national level—on particulate matter (PM) chemistry and its diverse origins in urban environments. It results [...] Read more.

The CARA program has been running since 2008 by the French reference laboratory for air quality monitoring (LCSQA) and the regional monitoring networks, to gain better knowledge—at a national level—on particulate matter (PM) chemistry and its diverse origins in urban environments. It results in strong collaborations with international-level academic partners for state-of-the-art, straightforward, and robust results and methodologies within operational air quality stakeholders (and subsequently, decision makers). Here, we illustrate some of the main outputs obtained over the last decade, thanks to this program, regarding methodological aspects (both in terms of measurement techniques and data treatment procedures) as well as acquired knowledge on the predominant PM sources. Offline and online methods are used following well-suited quality assurance and quality control procedures, notably including inter-laboratory comparison exercises. Source apportionment studies are conducted using various receptor modeling approaches. Overall, the results presented herewith underline the major influences of residential wood burning (during the cold period) and road transport emissions (exhaust and non-exhaust ones, all throughout the year), as well as substantial contributions of mineral dust and primary biogenic particles (mostly during the warm period). Long-range transport phenomena, e.g., advection of secondary inorganic aerosols from the European continental sector and of Saharan dust into the French West Indies, are also discussed in this paper. Finally, we briefly address the use of stable isotope measurements (δ¹⁵N) and of various organic molecular markers for a better understanding of the origins of ammonium and of the different organic aerosol fractions, respectively. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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18 pages, 4176 KiB

Open AccessArticle

Ammonia and PM_2.5 Air Pollution in Paris during the 2020 COVID Lockdown

by Camille Viatte, Jean-Eudes Petit, Shoma Yamanouchi, Martin Van Damme, Carole Doucerain, Emeric Germain-Piaulenne, Valérie Gros, Olivier Favez, Lieven Clarisse, Pierre-Francois Coheur, Kimberly Strong and Cathy Clerbaux

Atmosphere 2021, 12(2), 160; https://doi.org/10.3390/atmos12020160 - 27 Jan 2021

Cited by 32 | Viewed by 5928

Abstract

During the COVID-19 pandemic, the lockdown reduced anthropogenic emissions of NO₂ in Paris. NO₂ concentrations recorded in 2020 were the lowest they have been in the past 5 years. Despite these low-NO₂ levels, Paris experienced PM_2.5 pollution episodes, which [...] Read more.

During the COVID-19 pandemic, the lockdown reduced anthropogenic emissions of NO₂ in Paris. NO₂ concentrations recorded in 2020 were the lowest they have been in the past 5 years. Despite these low-NO₂ levels, Paris experienced PM_2.5 pollution episodes, which were investigated here based on multi-species and multi-platform measurements. Ammonia (NH₃) measurements over Paris, derived from a mini-DOAS (differential optical absorption spectroscopy) instrument and the Infrared Atmospheric Sounding Interferometer (IASI) satellite, revealed simultaneous enhancements during the spring PM_2.5 pollution episodes. Using the IASI maps and the FLEXPART model, we show that long-range transport had a statistically significant influence on the degradation of air quality in Paris. In addition, concentrations of ammonium (NH₄⁺) and PM_2.5 were strongly correlated for all episodes observed in springtime 2020, suggesting that transport of NH₃ drove a large component of the PM_2.5 pollution over Paris. We found that NH₃ was not the limiting factor for the formation of ammonium nitrate (NH₄NO₃), and we suggest that the conversion of ammonia to ammonium may have been the essential driver. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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22 pages, 2766 KiB

Open AccessArticle

Simultaneous Monitoring of Particle-Bound PAHs Inside a Low-Energy School Building and Outdoors over Two Weeks in France

by Céline Liaud, Sarah Chouvenc and Stéphane Le Calvé

Atmosphere 2021, 12(1), 108; https://doi.org/10.3390/atmos12010108 - 13 Jan 2021

Cited by 9 | Viewed by 2398

Abstract

The emergence of new super-insulated buildings to reduce energy consumption can lead to a degradation of the indoor air quality. While some studies were carried out to assess the air quality in these super-insulated buildings, they were usually focused on the measurement of [...] Read more.

The emergence of new super-insulated buildings to reduce energy consumption can lead to a degradation of the indoor air quality. While some studies were carried out to assess the air quality in these super-insulated buildings, they were usually focused on the measurement of gas phase pollutants such as carbon dioxide and volatile organic compounds. This work reports the first measurements of Polycyclic Aromatic Hydrocarbons (PAHs) associated with particles as a function of time and particle size in a low-energy building. The airborne particles were collected indoors and outdoors over three to four days of sampling using two three-stage cascade impactors allowing to sample simultaneously particles with aerodynamic diameter Dae > 10 µm, 2.5 µm < Dae < 10 µm, 1 µm < Dae < 2.5 µm, and Dae < 1 µm. The 16 US-EPA priority PAHs were then extracted and quantified by high-performance liquid chromatography (HPLC) coupled to fluorescence detection. The resulting total particle concentrations were low, in the ranges 3.73 to 9.66 and 0.60 to 8.83 µg m-3 for indoors and outdoors, respectively. Thirteen PAHs were always detected in all the samples. The total PAH concentrations varied between 290 and 415 pg m⁻³ depending on the particle size, the environment (indoors or outdoors) and the sampling period considered. More interestingly, the temporal variations of individual PAHs highlighted that high molecular weight PAHs were mainly associated to the finest particles and some of them exhibited similar temporal behaviors, suggesting a common emission source. The indoor-to-outdoor concentration ratios of individual PAH were usually found close to or less than 1, except during the event combining rainy conditions and limited indoor ventilation rate. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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23 pages, 5973 KiB

Open AccessArticle

Simultaneous Roadside and Urban Background Measurements of Submicron Aerosol Number Concentration and Size Distribution (in the Range 20–800 nm), along with Chemical Composition in Strasbourg, France

by Mélodie Chatain, Raphaël Alvarez, Aurélien Ustache, Emmanuel Rivière, Olivier Favez and Cyril Pallares

Atmosphere 2021, 12(1), 71; https://doi.org/10.3390/atmos12010071 - 6 Jan 2021

Cited by 15 | Viewed by 4657

Abstract

The adverse health impact of particles and ultrafine particles (UFP) is proven, highlighting the need of measuring the particle number concentration (PNC) dominated by UFP. So far, PNC had never been measured in the Strasbourg urban area (France). The present study on particle [...] Read more.

The adverse health impact of particles and ultrafine particles (UFP) is proven, highlighting the need of measuring the particle number concentration (PNC) dominated by UFP. So far, PNC had never been measured in the Strasbourg urban area (France). The present study on particle size distribution and PNC measurements by an UFP-3031 analyzer was conducted during winter 2019 on a background and a roadside multi-instrumented sites (Black Carbon, chemical speciation, particulate matter 10 μm or less in diameter—PM₁₀ mass). This paper shows significantly higher particle number concentrations of particles below 100 nm at the traffic site compared to the background site. The presence of a road axis thus mainly influences UFP, contrary to larger particles whose levels are more homogeneous over the agglomeration. During the measurement period, the nature of the particles (particle size contribution and chemical composition) was different between periods of high PM₁₀ mass concentrations and periods of high PNC. High PM₁₀ mass concentrations were associated with a high contribution of particles larger than 100 nm but they did not show specific chemical signature. On the other hand, during the periods with high PNC, the chemical composition was modified with an increase of the primary carbonaceous fraction compared to the periods with low PNC, but there was then no clear change in size distribution. Overall, this study illustrates that PM₁₀ mass concentrations were barely representative of UFP and PNC variations, confirming that the monitoring of the latter metrics is necessary to better evaluate the particles toxicity, knowing that this toxicity also depends on the particle’s chemical composition. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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24 pages, 1212 KiB

Open AccessArticle

Road Traffic Dynamic Pollutant Emissions Estimation: From Macroscopic Road Information to Microscopic Environmental Impact

by Giovanni De Nunzio, Mohamed Laraki and Laurent Thibault

Atmosphere 2021, 12(1), 53; https://doi.org/10.3390/atmos12010053 - 31 Dec 2020

Cited by 13 | Viewed by 3564

Abstract

Air pollution poses a major threat to health and climate, yet cities lack simple tools to quantify the costs and effects of their measures and assess those that are most effective in improving air quality. In this work, a complete modeling framework to [...] Read more.

Air pollution poses a major threat to health and climate, yet cities lack simple tools to quantify the costs and effects of their measures and assess those that are most effective in improving air quality. In this work, a complete modeling framework to estimate road traffic microscopic pollutant emissions from common macroscopic road and traffic information is proposed. A machine learning model to estimate driving behavior as a function of traffic conditions and road infrastructure is coupled with a physics-based microscopic emissions model. The up-scaling of the individual vehicle emissions to the traffic-level contribution is simply performed via a meta-model using both statistical vehicles fleet composition and traffic volume data. Validation results with real-world driving data show that: the driving behavior model is able to maintain an estimation error below 10% for relevant boundary parameter of the speed profiles (i.e., mean, initial, and final speed) on any road segment; the traffic microscopic emissions model is able to reduce the estimation error by more than 50% with respect to reference macroscopic models for major pollutants such as NO_x and CO₂. Such a high-resolution road traffic emissions model at the scale of every road segment in the network proves to be highly beneficial as a source for air quality models and as a monitoring tool for cities. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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23 pages, 6360 KiB

Open AccessArticle

Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

by Sarah Letaïef, Pierre Camps, Thierry Poidras, Patrick Nicol, Delphine Bosch and Romane Pradeau

Atmosphere 2020, 11(12), 1285; https://doi.org/10.3390/atmos11121285 - 28 Nov 2020

Cited by 4 | Viewed by 2805

Abstract

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on [...] Read more.

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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18 pages, 2721 KiB

Open AccessArticle

Short-Term Associations of Nitrogen Dioxide (NO₂) on Mortality in 18 French Cities, 2010–2014

by Magali Corso, Myriam Blanchard, Sylvia Medina and Vérène Wagner

Atmosphere 2020, 11(11), 1198; https://doi.org/10.3390/atmos11111198 - 4 Nov 2020

Cited by 7 | Viewed by 2295

Abstract

We present an analysis of short-term associations between ambient NO₂ and mortality according to cause, age-group, and period (cold and warm) in 18 areas in metropolitan France for the 2010–2014 period. Associations were estimated in each area using a generalized additive Poisson [...] Read more.

We present an analysis of short-term associations between ambient NO₂ and mortality according to cause, age-group, and period (cold and warm) in 18 areas in metropolitan France for the 2010–2014 period. Associations were estimated in each area using a generalized additive Poisson regression model, and effects were summarized in a meta-analysis. The percentage increase in mortality rate was estimated for a 10 µg m⁻³ increase in the NO₂ level in each area for each complete calendar year and for cold (November to April) and warm periods (May to October) in each year. We found that the NO₂ increase (lag of 0–1 days) was associated with a 0.75% increase of non-accidental mortality for all age-groups (95% confidence interval (CI): (0.4; 1.10)). During the warm period, this NO₂ increase was associated with a 3.07% increase in non-accidental mortality in the ≥75 years old group (95% CI: 1.97; 4.18). This study supports the short-term effects of NO₂ as a proxy of urban traffic pollution on mortality, even for concentrations below the maximum guideline of 40 µg m⁻³ set down by the European Air Quality Standards and the World Health Organization (WHO). Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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16 pages, 815 KiB

Open AccessArticle

Urban-Scale NO₂ Prediction with Sensors Aboard Bicycles: A Comparison of Statistical Methods Using Synthetic Observations

by Christophe Bertero, Jean-François Léon, Gilles Trédan, Mathieu Roy and Alexandre Armengaud

Atmosphere 2020, 11(9), 1014; https://doi.org/10.3390/atmos11091014 - 22 Sep 2020

Cited by 6 | Viewed by 2864

Abstract

Mobile devices for city-scale air quality monitoring is receiving increasing attention due to the advent of low-cost and miniaturized sensors. Mobility and crowdsensing have emerged as a new means to investigate the ambient air quality in urban areas. However, the design of the [...] Read more.

Mobile devices for city-scale air quality monitoring is receiving increasing attention due to the advent of low-cost and miniaturized sensors. Mobility and crowdsensing have emerged as a new means to investigate the ambient air quality in urban areas. However, the design of the network (e.g., number of sensors per unit area) and the scientific interpretation of collected data with an ad hoc method are still challenging. In this paper, we focus on the use of a fleet of private bicycles to monitor NO

_{2}

concentrations in the city of Marseille, France. The study is based on synthetic observations generated by means of a regional air quality simulation system at a spatial resolution of 25 m × 25 m and simulated bike trips that are randomly generated in the city. The bike trips correspond to a maximum of 4500 bike commuters and are generated using a web-based navigation service. Simulated bike tracks are validated using available statistics on bike counts. Each bike track is associated with the along-track corresponding NO

_{2}

concentrations collected from the air quality simulations and physical features on the ground collected from Open Street Map. Spatialization of the information collected aboard the bikes is tested by using three different algorithms: kriging, land-use regression (LUR) and neural network (NN). LUR and NN show that the fleet can be limited to below 100 bikes while the performance of kriging is steadily increasing with the number of bikes. Increasing the sample distance above 200 m also impairs the citywide prediction of simulated NO

_{2}

concentrations. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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23 pages, 5692 KiB

Open AccessArticle

Impact of Physics Parameterizations on High-Resolution Air Quality Simulations over the Paris Region

by Lei Jiang, Bertrand Bessagnet, Frederik Meleux, Frederic Tognet and Florian Couvidat

Atmosphere 2020, 11(6), 618; https://doi.org/10.3390/atmos11060618 - 11 Jun 2020

Cited by 10 | Viewed by 3267

Abstract

The accurate simulation of meteorological conditions, especially within the planetary boundary layer (PBL), is of major importance for air quality modeling. In the present work, we have used the Weather Research and Forecast (WRF) model coupled with the chemistry transport model (CTM) CHIMERE [...] Read more.

The accurate simulation of meteorological conditions, especially within the planetary boundary layer (PBL), is of major importance for air quality modeling. In the present work, we have used the Weather Research and Forecast (WRF) model coupled with the chemistry transport model (CTM) CHIMERE to understand the impact of physics parameterizations on air quality simulation during a short-term pollution episode on the Paris region. A lower first model layer with a 4 m surface layer could better reproduce the transport and diffusion of pollutants in a real urban environment. Three canopy models could better reproduce a 2 m temperature (T2) in the daytime but present a positive bias from 1 to 5 °C during the nighttime; the multi-urban canopy scheme “building effect parameterization” (BEP) underestimates the 10 m windspeed (W10) around 1.2 m s⁻¹ for the whole episode, indicating the city cluster plays an important role in the diffusion rate in urban areas. For the simulation of pollutant concentrations, large differences were found between three canopy schemes, but with an overall overestimation during the pollution episode, especially for NO₂ simulation, the average mean biases of NO₂ prediction during the pollution episode were 40.9, 62.2, and 29.7 µg m⁻³ for the Bulk, urban canopy model (UCM), and BEP schemes, respectively. Meanwhile, the vertical profile of the diffusion coefficients and pollutants indicated an important impact of the canopy model on the vertical diffusion. The PBL scheme sensitivity tests displayed an underestimation of the height of the PBL when compared with observations issued from the Lidar. The YonSei University scheme YSU and Boulac PBL schemes improved the PBL prediction compared with the Mellor–Yamada–Janjic (MYJ) scheme. All the sensitivity tests, except the Boulac–BEP, could not fairly reproduce the PBL height during the pollution episode. The Boulac–BEP scheme had significantly better performances than the other schemes for the simulation of both the PBL height and pollutants, especially for the NO₂ and PM_2.5 (particulate matter 2.5 micrometers or less in diameter) simulations. The mean bias of the NO₂, PM_2.5, and PM₁₀ (particulate matter 10 micrometers or less in diameter) prediction were −5.1, 1.2, and −8.6 µg m⁻³, respectively, indicating that both the canopy schemes and PBL schemes have a critical effect on air quality prediction in the urban region. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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33 pages, 46744 KiB

Open AccessArticle

High Resolution Chemistry Transport Modeling with the On-Line CHIMERE-WRF Model over the French Alps—Analysis of a Feedback of Surface Particulate Matter Concentrations on Mountain Meteorology

by Bertrand Bessagnet, Laurent Menut, Rémy Lapere, Florian Couvidat, Jean-Luc Jaffrezo, Sylvain Mailler, Olivier Favez, Romain Pennel and Guillaume Siour

Atmosphere 2020, 11(6), 565; https://doi.org/10.3390/atmos11060565 - 29 May 2020

Cited by 22 | Viewed by 5099

Abstract

Air pollution is of major concern throughout the world and the use of modeling tools to analyze and forecast the pollutant concentrations in complex orographic areas remains challenging. This work proposes an exhaustive framework to analyze the ability of models to simulate the [...] Read more.

Air pollution is of major concern throughout the world and the use of modeling tools to analyze and forecast the pollutant concentrations in complex orographic areas remains challenging. This work proposes an exhaustive framework to analyze the ability of models to simulate the air quality over the French Alps up to 1.2 km resolution over Grenoble and the Arve Valley. The on-line coupled suite of models CHIMERE-WRF is used in its recent version to analyze a 1 month episode in November–December 2013. As expected, an improved resolution increases the concentrations close to the emission areas and reduced the negative bias for Particulate Matter that is the usual weakness of air quality models. However, the nitrate concentrations seem overestimated with at the same time an overestimation of surface temperature in the morning by WRF. Different WRF settings found in the literature are tested to improve the results, particularly the ability of the meteorological model to simulate the strong thermal inversions in the morning. Wood burning is one of the main contributor of air pollution during the period ranging from 80 to 90% of the Organic Matter. The activation of the on-line coupling has a moderate impact on the background concentrations but surprisingly a change of Particulate Matter (PM) concentrations in the valley will affect more the meteorology nearby high altitude areas than in the valley. This phenomenon is the result of a chain of processes involving the radiative effects and the water vapor column gradients in complex orographic areas. At last, the model confirms that the surrounding glaciers are largely impacted by long range transport of desert dust. However, in wintertime some outbreaks of anthropogenic pollution from the valley when the synoptic situation changes can be advected up to the nearby high altitude areas, then deposited. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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21 pages, 3695 KiB

Open AccessArticle

Modelling Cyclists’ Multi-Exposure to Air and Noise Pollution with Low-Cost Sensors—The Case of Paris

by Jérémy Gelb and Philippe Apparicio

Atmosphere 2020, 11(4), 422; https://doi.org/10.3390/atmos11040422 - 22 Apr 2020

Cited by 12 | Viewed by 6395

Abstract

Cyclists are particularly exposed to air and noise pollution because of their higher ventilation rate and their proximity to traffic. However, few studies have investigated their multi-exposure and have taken into account its real complexity in building statistical models (nonlinearity, pseudo replication, autocorrelation, [...] Read more.

Cyclists are particularly exposed to air and noise pollution because of their higher ventilation rate and their proximity to traffic. However, few studies have investigated their multi-exposure and have taken into account its real complexity in building statistical models (nonlinearity, pseudo replication, autocorrelation, etc.). We propose here to model cyclists’ exposure to air and noise pollution simultaneously in Paris (France). Specifically, the purpose of this study is to develop a methodology based on an extensive mobile data collection using low-cost sensors to determine which factors of the urban micro-scale environment contribute to cyclists’ multi-exposure and to what extent. To this end, we developed a conceptual framework to define cyclists’ multi-exposure and applied it to a multivariate generalized additive model with mixed effects and temporal autocorrelation. The results show that it is possible to reduce cyclists’ multi-exposure by adapting the planning and development practices of cycling infrastructure, and that this reduction can be substantial for noise exposure. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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21 pages, 5642 KiB

Open AccessArticle

Characterization of Aerosol Physical and Optical Properties at the Observatoire Pérenne de l’Environnement (OPE) Site

by Antoine Farah, Paolo Villani, Clemence Rose, Sebastien Conil, Laurent Langrene, Paolo Laj and Karine Sellegri

Atmosphere 2020, 11(2), 172; https://doi.org/10.3390/atmos11020172 - 7 Feb 2020

Cited by 8 | Viewed by 3525

Abstract

The Observatoire Pérenne de l’Environnement (OPE) station is a rural background site located in North-Eastern France. Besides emissions from agricultural activities, the site is located far from local emissions but at an even distance from the intense emission zones of Western Germany to [...] Read more.

The Observatoire Pérenne de l’Environnement (OPE) station is a rural background site located in North-Eastern France. Besides emissions from agricultural activities, the site is located far from local emissions but at an even distance from the intense emission zones of Western Germany to the north-east and the Paris area to the south-west. In the paper, we report and analyze almost six years of measurements (1 May 2012 to 31 December 2018) of the optical and physical properties of aerosol particles. Based on aerosol optical and physical measurements combined with air mass back-trajectories, we investigate the dependence of these properties on air mass type. Two distinct equivalent black carbon (EBC) sources—origins-fossil fuel (FF) and biomass burning (BB)— were identified. FF was the dominant source of EBC (>70%) but showed a very marked seasonal variation. BB fraction is found higher during the cold seasons in the order of 35% (0.1 µg m⁻³) against 17% (0.05 µg m⁻³) during the warm seasons. The highest EBC and N_0.54–1.15 (particles whose diameter ranged from 0.54 to 1.15 µm) median concentrations were observed during the night time and during the cold seasons compared to the warmer seasons, indicating primary sources trapped within a thin boundary layer (BL). A different behavior is found for N_10–550 (particles whose diameter ranged from 10 to 550 nm) and coarse mode particles (N_1.15–4.5, i.e., particles whose diameter ranged from 1.15 to 4.5 µm) median concentrations, which were observed during the warm seasons compared to the cold seasons, indicating rather biogenic secondary sources for the smaller particles, and potentially primary biogenic sources for the coarse mode particles. The scattering and absorption coefficients and single scattering albedo (SSA) show the same seasonal variations like the ones of N_0.54–1.15 concentrations, indicating that particles larger than 500 nm seemed to contribute the most to the optical properties of the aerosol. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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22 pages, 18818 KiB

Open AccessArticle

Large-Eddy Simulations with an Immersed Boundary Method: Pollutant Dispersion over Urban Terrain

by Franck Auguste, Christine Lac, Valery Masson and Daniel Cariolle

Atmosphere 2020, 11(1), 113; https://doi.org/10.3390/atmos11010113 - 18 Jan 2020

Cited by 4 | Viewed by 4089

Abstract

In urban canopies, the variability of pollution may be influenced by the presence of surface heterogeneities like orography and buildings. Using the Meso-NH model enhanced with an immersed boundary method (IBM) to represent accurately the impact of the 3D shape of buildings on [...] Read more.

In urban canopies, the variability of pollution may be influenced by the presence of surface heterogeneities like orography and buildings. Using the Meso-NH model enhanced with an immersed boundary method (IBM) to represent accurately the impact of the 3D shape of buildings on the flow, large-eddy simulations are performed over city of Toulouse (France) with the dispersion of a plume following a plant explosion on 21 September 2001. The event is characterized by a large quantity of nitrogen dioxide released in a vertical column after the explosion, quickly dispersed by a moderate wind prevailing in the lower atmospheric layers. Assuming a passive pollutant, the model develops a realistic plume dispersion. A sensitivity analysis of the advection scheme to the spread is presented. The limited population’s exposure to pollution developed by the model appears in good agreement with previous health studies. Beyond this case, IBM is a promising way to represent flow interaction with buildings and orography in atmospheric models for urban applications. Full article

(This article belongs to the Special Issue Air Pollution and Environment in France)

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