Patrick Augustin 1, Sylvain Billet 2 , Suzanne Crumeyrolle 3, Karine Deboudt 1, Elsa Dieudonné 1 , Pascal Flament 1 , Marc Fourmentin 1 , Sarah Guilbaud 1, Benjamin Hanoune 4 , Yann Landkocz 2, Clémence Méausoone 2, Sayahnya Roy 5, François G. Schmitt 5, Alexei Sentchev 5 and Anton Sokolov 1
1 Univ. Littoral Côte d’Opale, UR 4493—LPCA—Laboratoire de Physico-Chimie de l’Atmosphère, 59140 Dunkerque, France;
2 Univ. Littoral Côte d’Opale, SFR Condorcet FR CNRS 3417, UR 4492—UCEiV—Unité de Chimie Environnementale et Interactions sur le Vivant, 59140 Dunkerque, France;
3 Univ. Lille, CNRS, UMR 8518—LOA—Laboratoire d’Optique Atmosphérique, 59000 Lille, France;
4 Univ. Lille, CNRS, UMR 8522—PC2A—Physico-Chimie des Processus de Combustion et de l’Atmosphère, 59000 Lille, France;
5 Univ. Lille, Univ. Littoral Côte d’Opale, CNRS, UMR 8187—LOG—Laboratoire d’Océanologie et de Géosciences, F 62930 Wimereux, France;
An atmospheric mobile unit was implemented during a field campaign performed at a representative site of urbanized and industrialized coastal environment of the North Sea (Northern France), to study the impact of sea breeze dynamics on aerosol properties, and especially their toxicity. This unit combined aerosol samplers, two scanning lidars (Doppler and elastic), two aerosol particle sizers and an air-liquid interface (ALI, Vitrocell) in vitro cell exposure device. This study is one of the first to bring cell cultures into the field to evaluate the harmfulness of a real environmental compartment. Atmospheric toxicity in the presence or absence of sea breeze was demonstrated in human bronchial cells exposed in the field using an ALI exposure system. The study showed the sensitivity of the developed device to discriminate the mechanisms of toxic action activated when exposed to different atmospheres.
Sea breeze (SB) phenomena may strongly influence air quality and lead to important effects on human health. In order to study the impact of SB dynamics on the properties and toxicity of aerosols, an atmospheric mobile unit was deployed during a field campaign performed in an urbanized and industrialized coastal area in Northern France. This unit combines aerosol samplers, two scanning lidars (Doppler and elastic) and an air-liquid interface (ALI, Vitrocellfi) in vitro cell exposure device. Our study highlights that after the passage of an SB front, the top of the atmospheric boundary layer collapses as the thermal internal boundary layer (TIBL) develops, which leads to high aerosol extinction coefficient values (>0.4 km−1) and an increase of PM2.5 and NOx concentrations in the SB current. The number-size distribution of particles indicates a high proportion of fine particles (with diameter below 500 nm), while the volume-size distribution shows a major mode of coarse particles centered on 2–3 µm. Individual particle analyses performed by cryo-transmission scanning electron microscopy (cryo-TSEM)-EDX highlights that submicronic particles contained a high fraction of secondary compounds, which may result from nucleation and/or condensation of condensable species (vapors or gaseous species after photo-oxidation). Secondary aerosol (SA) formation can be enhanced in some areas, by the interaction between the SB flow and the upper continental air mass, particularly due to the effect of both turbulence and temperature/humidity gradients between these two contrasting air masses. Potential areas of SA formation are located near the ground, during the SB front passage and in the vicinity of the SB current top. During the sea breeze event, an increase in the oxidative stress and inflammation processes in exposed lung cells, compared to the unexposed cells, can also be seen. In some instances, short singularity periods are observed during SB, corresponding to a double flow structure. It consists of two adjacent SB currents that induce an important increase of the TIBL top, improving the pollutants dispersion. This is associated with a substantial decrease of aerosol mass concentrations.