The study, led by Theresa Mathes of the Technische Universität Berlin and the Leibniz Institute for Tropospheric Research, together with colleagues from the University of Leeds, Stockholm University, Uppsala University and TROPOS in Leipzig, was carried out as part of the ARTofMELT expedition, which sailed from Svalbard between 8 May and 15 June 2023. The campaign’s broader goal was to understand how atmospheric rivers, narrow corridors of warm, moist air, trigger the onset of sea ice melt. But the flux measurements collected along the way, published in the journal Atmospheric Chemistry and Physics, provide one of the longest continuous eddy covariance records of particle exchange ever obtained over the Arctic Ocean, and they carry implications that reach well beyond the expedition’s original purpose.

Aerosol particles matter enormously in the Arctic. They scatter and absorb sunlight directly, and they act as cloud condensation nuclei and ice nucleating particles, shaping the formation, brightness and lifetime of clouds. Because particle concentrations in the polar boundary layer are often very low, particularly in autumn, even small changes in the particle budget can ripple through cloud microphysics and the regional radiation balance. The Arctic is warming two to seven times faster than the global average since 1979, a phenomenon known as Arctic amplification, and shifts in the sources and sinks of aerosols are one of the feedbacks that models struggle to capture. Yet direct observations of turbulent particle fluxes over sea ice have been strikingly scarce, with most previous ship-based campaigns lasting only days to a couple of weeks.

The technical challenge of making these measurements from a moving ship is considerable. Eddy covariance, the gold-standard technique, requires capturing rapid fluctuations in vertical wind speed and particle concentration simultaneously, at sampling rates of around 10 hertz. The team mounted a sonic anemometer 20.3 meters above the surface on Oden’s foremast, alongside a heated inlet feeding a mixing-type condensation particle counter capable of detecting particles down to 7 nanometers. Because the instrument sampled air through a long tube, the researchers had to correct carefully for the time lag between wind and concentration fluctuations, for particle losses to the tubing walls, and for the motion and flow distortion of the ship itself, using motion sensors and computational fluid dynamics corrections developed for Oden. Ship exhaust contamination, an ever-present hazard on a vessel, was rigorously screened out, removing 17 percent of the data.

To interpret the fluxes, the team classified the surface upwind of the ship into three categories: closed ice, leads, and open water. This was done automatically using a machine-learning image segmentation algorithm, a random forest classifier, applied to hourly photographs taken by cameras on the ship’s decks, with the relevant camera chosen according to the prevailing wind direction. The approach allowed the researchers to attribute each 20-minute flux measurement to the type of surface it had sampled, something few previous studies have done systematically.

The headline result is a study in contrasts. Under low to moderate turbulence, closed ice behaved as expected: it was a net sink for particles, with a median deposition flux of −0.02 × 10⁶ particles per square meter per second, and deposition dominated roughly 70 percent of the intervals measured over ice. But when the wind picked up, the picture reversed. During eight high wind speed events identified during the campaign, five showed net particle emission, and during the longest of these, a storm on 24 to 26 May with winds reaching 19 meters per second, the team recorded net emission fluxes of up to 0.98 × 10⁶ particles per square meter per second, a statistically robust figure with a 95 percent confidence interval excluding zero. The inferred emission strength, calculated by subtracting a modeled deposition flux from the measured net flux, peaked at 1.57 × 10⁶ particles per square meter per second during a second storm at the end of May.

The most likely culprit is blowing snow. Strong winds lift snow grains from the surface, and because Arctic snow contains sea salt, sulfate, nitrate, organic matter and even black carbon, the sublimation of these wind-blown particles releases aerosols into the boundary layer. The particle size distributions measured during the storm events support this interpretation: elevated concentrations appeared across a broad range of diameters, roughly 30 to 300 nanometers, rather than showing the narrow nucleation-and-growth signature expected from new particle formation driven by precursor gases. The researchers also found that the strength of the particle flux correlated strongly with friction velocity, a measure of near-surface turbulence, with a correlation coefficient of 0.88, reinforcing the link between turbulent wind stress and particle exchange. The threshold wind speed for blowing snow is not fixed; it depends on temperature and snow properties, and at low temperatures mobilization could begin at winds as gentle as 6 meters per second.

Over leads and open water, the story was more nuanced. Both surfaces showed a mixture of emission and deposition events, with median fluxes close to zero, suggesting that while open ocean and cracks in the ice can act as particle sources, through mechanisms such as bubble bursting and sea spray, their net contribution during the campaign was modest. The researchers note that whitecaps in pack ice regions are smaller and less frequent than in the open ocean, which may explain the weak net emission observed. They also caution that open water periods were underrepresented in the filtered dataset because the ship was typically underway when open water was present, and surface classification was restricted to periods of slow drift.

What makes these findings consequential is the trajectory of the Arctic itself. Climate models project continued sea ice loss and a corresponding expansion of open water, which is expected to change the frequency and intensity of the particle exchange processes documented here. As the ice retreats, local particle sources, whether from leads, open water or wind-blown snow, are likely to play a growing role in the regional aerosol budget, with knock-on effects for cloud formation and the surface energy balance. Whether the net climatic effect is cooling, through brighter clouds reflecting more sunlight, or warming, through changes in cloud lifetime and phase, remains poorly constrained, and competing source and sink processes make the outcome genuinely uncertain.

By providing hard observational constraints on particle fluxes over three distinct surface types, the ARTofMELT dataset gives modelers something they have long lacked: direct numbers against which to test deposition schemes and emission parameterizations in the High Arctic. The team’s data are publicly available through the PANGAEA repository. As the researchers conclude, quantifying particle deposition on closed ice and emissions from leads and storm-whipped snowfields is a step toward reducing the stubborn uncertainties that still surround Arctic aerosol-cloud-climate interactions, in a region where the stakes of getting the feedbacks right could not be higher.

Subject of Research: Turbulent aerosol particle exchange between the atmosphere and sea ice, leads and open water in the High Arctic

Article Title: Turbulent atmospheric particle fluxes in the High Arctic: surface type dependence and variability

Article References: Mathes, T., Brooks, I., Murto, S., Tjernström, M., Kojoj, J., Zieger, P., Prytherch, J., Wehner, B., & Held, A. (2026). Turbulent atmospheric particle fluxes in the High Arctic: surface type dependence and variability. Atmospheric Chemistry and Physics, 26(19), 14507-14530. https://doi.org/10.5194/acp-26-14507-2026

Image Credits: AI Generated

DOI: 10.5194/acp-26-14507-2026

Keywords: Arctic, aerosol particles, eddy covariance, sea ice, blowing snow, particle fluxes, cloud condensation nuclei, Arctic amplification, leads, sea spray aerosol, ARTofMELT, dry deposition

The team carried out their experiments in a closed-circuit recirculating wind tunnel at the Experimental Center of Desert Forestry in Dengkou, Inner Mongolia. The facility’s test section stretches 13 metres, with a cross section 2 metres wide and 2 metres high, and four axial fans can drive wind speeds continuously from 0 to 20 metres per second. The researchers used dust sieved from the upper layers of local cropland soil, dried it in an oven at 105 degrees Celsius to standardize moisture, and restricted it to particles smaller than 63 micrometres. This choice matters: the finest of these particles are the ones most relevant to human health and long-range atmospheric transport, yet they are also the hardest to pin down in deposition measurements.

The experimental protocol unfolded in two stages. First, a strong-wind loading phase at 14 metres per second for roughly five minutes eroded the soil bed and filled the tunnel with a recirculating cloud of airborne dust. Then the soil source was sealed under steel plates to prevent further emission, and the wind was dropped to one of four target levels: 0, 2, 4, or 6 metres per second. Twenty-five cylindrical acrylic collection trays, each with a 10-centimetre radius, were laid out on the tunnel floor. Five trays were retrieved at each of five sampling times — 30, 60, 90, 120, and 180 minutes — and their captured dust was weighed on an analytical balance accurate to a tenth of a milligram. Crucially, no sticky coatings or adhesives were used, so the trays recorded net accumulation: the balance between particles arriving, rebounding, and being swept away again.

To make sense of the accumulating masses, the researchers fitted a first-order kinetic model in which the retained mass approaches an asymptote exponentially. The fit yields four interpretable quantities: the asymptotic retained mass, the effective net-accumulation rate coefficient, a characteristic timescale equal to the reciprocal of that coefficient, and the initial net accumulation flux, which is the product of the asymptote and the rate coefficient. The model performed remarkably well, with coefficients of determination between 0.889 and 0.992, and three-quarters of the fits exceeding 0.95. This means a single effective timescale captures the whole deposition process for every combination of wind speed and particle size tested — a useful simplification for anyone trying to parameterize dust removal.

The results revealed a striking pattern. In still air, fine particles accumulated slowly and almost linearly: the characteristic timescale for particles below 2.5 micrometres was about 4.2 hours, and for those below 10 micrometres about 1.4 hours. Coarse particles, by contrast, reached their asymptotes within roughly an hour, dominated by straightforward gravitational settling. When the wind was raised to 2 metres per second, everything changed. The characteristic time for the finest particles collapsed from 4.2 hours to just 0.3 hours — an order-of-magnitude acceleration — while the rate coefficient jumped from 0.24 to 3 per hour. The initial net accumulation flux was highest at 2 metres per second for all size classes from PM2.5 through PM30, and quadratic fits across the four wind speeds suggested a model-implied optimum somewhere between 2 and 3 metres per second.

At higher winds, the picture reversed. At 4 metres per second, deposition remained fast but the ultimate retained mass fell by roughly 25 to 60 percent below still-air values, especially for fine and medium particles. At 6 metres per second, the suppression became dramatic: the asymptotic retained mass for PM2.5 and PM10 dropped by about an order of magnitude relative to calm conditions, indicating near-complete inhibition of effective accumulation even though the rate coefficients stayed high. An auxiliary screening test identified an apparent critical wind-speed range of 5.87 to 6.01 metres per second for mobilizing dust from the tray surface, placing the 6-metre-per-second treatment right at the edge of re-entrainment. In other words, stronger winds kept particles aloft longer and stripped away what had landed, while a gentle breeze delivered particles to the surface without dislodging them.

The particle-size distributions of the retained dust added a fascinating clue about mechanism. At 2 metres per second, the median diameter of accumulated material grew from 7.1 to 9.8 micrometres between the half-hour and three-hour samples, and the modal diameter shifted from 4.3 to 18.3 micrometres. The researchers suggest this effective coarsening may reflect shear-induced aggregation: moderate turbulence increases collisions between dust particles, allowing small ones to stick together into transient clusters that settle faster. This interpretation aligns with a rich literature on cohesive sediments in two-phase flows, where aggregate size consistently peaks at intermediate shear — strong enough to bring particles together, too weak to break the clusters apart. The geometry is suggestive too: the volume associated with the observed diameter shift corresponds to roughly two to three similarly sized primary particles merging, though the authors caution that size-selective deposition alone could also produce the pattern.

Quantified against a non-decreasing benchmark built from the same data, the departure from conventional expectations is substantial. For the PM2.5 through PM40 classes, the observed initial flux at 2 metres per second exceeded the monotonic benchmark by 15 to 72 percent. At 6 metres per second, the observed flux fell 45 to 91 percent below the benchmark — meaning deposition-only schemes could overestimate net accumulation by factors of roughly 2 to 11 for the affected sizes under such conditions. The physics is consistent with what is known about near-surface turbulence: for 2-to-10-micrometre particles, settling velocities are only fractions of a millimetre per second, so penetration of the thin viscous sublayer above the surface depends on turbulent diffusion rather than gravity. The calculated Rouse numbers, well below unity, confirm that turbulent mixing dominates over settling for these sizes — and at 2 metres per second the turbulence is strong enough to deliver particles downward but too weak to resuspend them.

The implications ripple outward through the global dust cycle. If net dry deposition in source regions under calm post-storm winds is higher than models currently predict, atmospheric dust loads would decline faster than simulated, shortening transport distances and reducing the dust reaching remote oceans and high latitudes. Conversely, where background winds are stronger, resuspension could extend particle lifetimes and enhance long-range transport. This helps explain a persistent bias in climate models, which tend to underestimate near-source deposition of coarse and accumulation-mode particles while overestimating dust burdens far downwind. The authors are careful about limitations: the experiments used a single agricultural soil dust, tray geometry and smooth acrylic surfaces may influence rebound, soil moisture and particle shape were not varied, and the inferred optimum rests on only four wind-speed levels. Still, the size-resolved kinetic parameters they report — asymptotic mass, rate coefficient, timescale, and initial flux — offer concrete benchmarks for building coupled deposition-retention-resuspension schemes. The gentle breeze, it turns out, is the atmosphere’s own dust vacuum, and models are only now learning to see it.

Subject of Research: Size-resolved kinetics of mineral dust dry deposition under calm and low-wind conditions

Article Title: Non-monotonic response of net dust deposition kinetics to low wind speeds

Article References: Jia, R., Ba, C., Zhang, C., Kuang, W., Liu, Y., Wang, Z., Liu, F., Xin, Z., Liu, Y., Ma, Q., Zong, L., Liang, W., Qian, J., & Liu, Z. (2026). Non-monotonic response of net dust deposition kinetics to low wind speeds. Atmospheric Chemistry and Physics, 26(19), 14245-14258. https://doi.org/10.5194/acp-26-14245-2026

Image Credits: AI Generated

DOI: 10.5194/acp-26-14245-2026

Keywords: mineral dust, dry deposition, wind tunnel, atmospheric aerosols, dust cycle, turbulence, particle aggregation, re-entrainment, deposition parameterization, atmospheric chemistry, climate modeling, PM2.5

The study, led by Jesse Bash of the US Environmental Protection Agency, now at the Norwegian Meteorological Institute, together with colleagues from the EPA, Environment and Climate Change Canada, and partner institutions, scrutinized the Surface Tiled Aerosol and Gaseous Exchange option, known as STAGE, in version 5.3.2 of the Community Multiscale Air Quality model, or CMAQ. STAGE is a unified framework that estimates both dry deposition, the uptake of gases by surfaces, and bidirectional exchange, the two-way traffic of gases between the atmosphere and soils or vegetation. What makes STAGE distinctive is that it applies the same resistance model to every modeled gas, whether that gas only deposits, like nitric acid, or can flow in both directions, like ammonia. That consistency matters, because in earlier versions of CMAQ, ammonia bidirectional exchange and the deposition of all other species were handled by two separate, parallel resistance schemes with different structural assumptions.

The mathematical heart of STAGE is a resistance analog borrowed from electrical circuit theory, following the widely used parameterizations of Nemitz and colleagues from 2001 and Massad and colleagues from 2010. The flux of a trace gas is driven by the difference between the ambient concentration and a compensation point concentration at the surface, divided by the aerodynamic resistance. For ammonia, the compensation point is built from a two-layer canopy and soil model: gases diffuse through leaf boundary layers, stomata, cuticles, and in-canopy air, with each pathway assigned its own resistance. The model even solves for the leaf-level compensation point using a system of equations analogous to Kirchhoff’s current law, balancing exchange between the atmosphere, stomata, cuticular surfaces, and the ground. When the compensation points are set to zero, the framework collapses gracefully into a conventional dry deposition velocity, which is precisely what allows one model to serve both unidirectional and bidirectional species.

Several technical refinements were introduced to make this framework work at regional scale. Deposition to wet leaf surfaces, previously treated as instantaneous diffusion into canopy water, now uses a mass transfer formulation adapted from CMAQ’s aqueous chemistry module, accounting for gaseous diffusivity and bulk accommodation into roughly spherical droplets sitting on hydrophobic leaves. The depth of surface moisture is derived from relative humidity using Brunauer-Emmett-Teller adsorption theory calibrated against leaf wetness observations, and droplet radius follows from that water depth and the leaf area index. In-canopy aerodynamic resistance is computed by integrating eddy diffusivity through the canopy using a momentum attenuation approach. Soil processes were also updated: the diffusive length for soil gas exchange was increased to two centimeters to match the measurements underlying the model, and soil ammonium availability is now estimated with a nonlinear sorption curve rather than a fixed solution fraction.

To test whether all this machinery reflects reality, the team turned the regional model into a field-scale box model written in the R statistical language, using identical resistance parameterizations, and ran it against micrometeorological flux measurements from two North Carolina sites. The first was a managed, unfertilized 15-hectare grass field at Duke Forest, where fluxes of ammonia, nitric acid, and sulfur dioxide were measured with a MARGA instrument during the second half of 2012. The second was a 200-hectare fertilized corn field near Lillington, where ammonia gradients were measured with a continuous-flow wet denuder system in 2007. When the box model was fed observed soil and vegetation ammonia emission potentials, the compensation points that quantify how much ammonia the soil and plant tissues are ready to release, the modeled fluxes of all three gases agreed well with observations, with mean biases within or near the reported measurement uncertainty.

The trouble emerged when the model was run with the default tabular values built into CMAQ. At the Duke Forest grassland, the defaults for soil and vegetation emission potentials, a soil gamma of 20 and an apoplast gamma of 247, produced a simulated mean net deposition of minus 1.3 nanograms per square meter per hour, while the towers actually recorded a mean evasive flux of 8.4 nanograms per square meter per hour in the opposite direction. In plain terms, the model said the grassland was absorbing ammonia when it was actually emitting it. Sensitivity experiments showed the modeled flux was most sensitive to the vegetation emission potential, and that perturbing resistances alone could not reverse the sign of the error. The measured compensation points at the site simply exceeded the tabular assumptions, which were drawn from parameterizations based on annual nitrogen deposition fields for non-agricultural land.

The corn field told a more encouraging but nuanced story. Using median measured soil ammonium, soil pH, and an apoplast emission potential of 153.5 reported in earlier work, the model captured the observed fluxes with a normalized mean bias of minus 23.4 percent, rising to 40.5 percent with the default parameterizations. The site also displayed a persistent mid-morning emission peak that the model could not fully explain. Dew on the leaves carried a high emission potential, but there was not enough ammonium in the dew, and the dew dried too early, to account for emissions that continued between eight and eleven in the morning on a dry canopy. The authors speculate that wetting and drying of ammonium-rich exposed soil between the rows, a process the soil moisture probes missed, may drive the morning pulse, contrasting with earlier dew-evaporation explanations at a Colorado grassland.

The decisive test came at continental scale. The team compared an annual 2016 CMAQ simulation against ammonia retrievals from the Cross-Track Infrared Sounder, a satellite instrument capable of detecting ammonia down to roughly half a part per billion under typical conditions. The model captured the broad magnitude and spatial patterns of satellite-observed ammonia, but the biases were revealing. CMAQ overestimated concentrations by 0.5 to 0.9 parts per billion on average in intensely agricultural regions such as California, the Upper Midwest, and eastern North Carolina, while underestimating observations across the Great Plains and other vegetated areas, with a broad shortfall of roughly one to two parts per billion over non-agricultural land. That pattern mirrors the grassland box model result almost exactly, pointing to a common cause: default emission potentials for natural vegetation and soils that sit at the low end of what field measurements show.

The implications extend beyond model diagnostics. The team estimates that of the 10.3 megatonnes of nitrogen applied as fertilizer to row crops in the 2016 simulation, about 0.5 megatonnes, an emission factor of 4.8 percent, was re-emitted as ammonia, a figure consistent with published ranges. Deposition peaked near 30 kilograms of nitrogen per hectare downwind of agricultural sources in eastern North Carolina, within measured values but higher than some earlier net deposition estimates for the region. The authors conclude that raising the grassland vegetation emission potential by about 30 percent and the soil surface emission potential roughly fivefold would better match both the Duke Forest observations and the satellite data, changes that remain well within the natural variability reported across measurement studies. Because non-agricultural land covers roughly three quarters of the terrestrial surface in the model domain, the path forward is clear: more micrometeorological flux measurements and soil and vegetation chemistry across different land uses, soil types, and growth stages. The multi-resolution evaluation strategy, spanning flux towers, monitoring networks, and satellites, offers the modeling community a template for building the next generation of air-surface exchange models on firmer empirical ground.

Subject of Research: Evaluation of bidirectional ammonia, nitric acid, and sulfur dioxide air-surface exchange in the CMAQ model's STAGE deposition option against field, network, and satellite observations

Article Title: Evaluation of HNO3, SO2, and NH3 in the Surface Tiled Aerosol and Gaseous Exchange (STAGE) option in the Community Multiscale Air Quality Model version 5.3.2 against field-scale, in situ and satellite observations

Article References: Bash, J. O., Walker, J. T., Wu, Z., Rumsey, I. C., Murphy, B., Hogrefe, C., Fahey, K. M., Pye, H. O. T., Jones, M. R., Appel, K. W., Shephard, M. W., Alnsour, N. I., & Cady-Periera, K. E. (2026). Evaluation of HNO 3 , SO 2 , and NH 3 in the Surface Tiled Aerosol and Gaseous Exchange (STAGE) option in the Community Multiscale Air Quality Model version 5.3.2 against field-scale, in situ and satellite observations. Geoscientific Model Development, 19(19), 9377-9393. https://doi.org/10.5194/gmd-19-9377-2026

Image Credits: AI Generated

DOI: 10.5194/gmd-19-9377-2026

Keywords: ammonia, air quality modeling, CMAQ, STAGE, dry deposition, bidirectional exchange, satellite observations, CrIS, grassland flux, emission potential, nitrogen deposition, particulate matter

The study focused on the coast of Newfoundland and Labrador, where waves from the Atlantic Ocean crash against an extensive shoreline and strong winds whip spray far inland. According to the researchers, this is close to a worst-case scenario for sea-spray-driven PFAS transport: abundant wind, crashing surf and a long coastline all combine to maximise the generation of marine aerosols. If the ocean were truly pumping significant quantities of forever chemicals into coastal environments through spray, the team reasoned, Newfoundland would be one of the places where the signal would be unmistakable. Senior author Cora Young, an atmospheric chemist and Guy Warwick Rogers Chair in York University’s Faculty of Science, said the location was chosen precisely because it offered the ideal conditions to detect such an effect.

We designed this study specifically to see if sea spray was contributing to a mobilization of PFAS in coastal regions and Newfoundland is a great place to do that, Young explained, noting that it is a marine location and very windy, so the team expected quite a lot of PFAS from sea spray. Instead, she said, the researchers were quite surprised that they did not see anything indicating sea spray was contributing to PFAS in the area. The finding directly contradicts the expectation, rooted in earlier modelling and laboratory work, that the ocean-to-land transfer of these chemicals through aerosols represents a significant and direct exposure pathway for people and ecosystems near the coast.

To test the hypothesis rigorously, the team moved beyond simulations and carried out on-the-ground field work. Lead author Daniel Persaud, a PhD student at York, together with Young and their collaborators, collected both wet and dry deposition samples at several locations stretching up to 30 kilometres from the eastern coast. Wet deposition refers to PFAS delivered by precipitation such as rain, while dry deposition captures the dust and particles, along with gases, that settle out of the atmosphere onto the ground. Measuring both pathways matters, because many studies record only one or the other, and the balance between them shapes how scientists estimate where forever chemicals ultimately land.

The sampling sites were forested watersheds within the Newfoundland and Labrador Boreal Ecosystem Latitudinal Transect, a network of study locations chosen because they are all influenced by marine aerosols and lie close to the ocean. Because the sites are windy and near the water, the researchers expected a strong marine-aerosol signal in their chemistry. To track it, they used sodium as a tracer of sea spray, since sodium is abundant in ocean-derived particles. Persaud said the measured PFAS showed little association with sodium, indicating that the forever chemicals found at the sites were not arriving with the salt spray from the Atlantic.

That does not mean the landscape was clean. The researchers did detect PFAS at every study site, but the pattern of compounds pointed to a different origin. They mostly found perfluoroalkyl acids, a subclass of PFAS that includes perfluoroalkyl carboxylic acids and perfluoroalkanesulfonic acids. These substances are not produced from local sources in Newfoundland. Instead, the evidence suggested they were the atmospheric breakdown products of PFAS precursor compounds that had been emitted elsewhere, transformed in the air during long-range transport, and then deposited on the island. In other words, the chemicals arrived from distant industrial and commercial centres, not from the waves at the shore.

The likely sources of those precursors lie elsewhere in Canada and the United States, and potentially even further afield. PFAS and their precursors are typically found in firefighting foams, non-stick materials and performance chemicals, and they are notorious for their ability to travel long distances through the atmosphere, reaching even the Arctic. Because perfluoroalkyl acids are extremely persistent and can bioaccumulate in living organisms, their continued deposition in remote regions raises ongoing environmental concerns. The new results do not make those concerns disappear; they simply redirect attention away from the ocean surface and back toward atmospheric transport of emissions from faraway sources.

The implications may extend well beyond eastern Canada. Young noted that Newfoundland offers something close to a perfect storm for sea-spray generation, with driving wind, crashing waves and an extensive coastline that together maximise the amount of aerosol produced. If sea spray were a major route for moving PFAS from ocean to land, it should have shown up there. According to Young, this sort of sea spray is really not a major source of global pollution according to the study. That conclusion, she suggested, amounts to good news: researchers had worried that PFAS could move from ocean to land and back again indefinitely, but the field evidence indicates the problem is not as large as feared.

One of the study’s most instructive findings concerned the role of dry deposition. The team measured both wet and dry deposition, but that combined approach is not universally practised, and their results underline how important it is to do so in order to understand the full impact of PFAS in the environment. Young said she still finds it surprising that dry deposition remains so important even in a place like Newfoundland, where rainfall is frequent. The observation suggests that in many other landscapes, from remote deserts to the Arctic, the settling of particle-bound and gaseous PFAS may be a larger contributor than precipitation alone would indicate, and that studies relying only on rain and snow could substantially underestimate total deposition.

Persaud said the distinction between wet and dry pathways helps researchers better predict where forever chemicals will be found as they move around the globe and where they will ultimately end up, benefiting not only his team but other researchers going forward. The work was a collaboration with scientists at Memorial University in St. John’s, where Young previously worked and collected samples, the Canadian Forest Service and Natural Resources Canada in Corner Brook, and the Aquatic Contaminants Research Division of Environment and Climate Change Canada in Burlington, Ontario. The paper, titled The Occurrence of Legacy Per- and Polyfluoroalkyl Substances (PFAS) Deposited along a Latitudinal Transect in Newfoundland and Labrador, Canada, was published in the Royal Society of Chemistry journal Environmental Science: Processes & Impacts under DOI 10.1039/D6EM00257A. For coastal residents wondering whether summer sea spray carries a hidden dose of forever chemicals, the answer from this windswept corner of Canada appears to be reassuring: the ocean, at least, is not the culprit it was made out to be.

Subject of Research: Atmospheric deposition of PFAS forever chemicals in coastal Newfoundland and the role of sea spray as a transport pathway

Article Title: Exposure to forever chemicals through sea spray may be overblown

Article References: Exposure to forever chemicals through sea spray may be overblown. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: PFAS, forever chemicals, sea spray, marine aerosols, Newfoundland and Labrador, atmospheric deposition, wet deposition, dry deposition, perfluoroalkyl acids, long-range transport, York University, environmental chemistry