The research, published in the journal Environmental Monitoring and Assessment, was carried out by Luka Vukić, Anđela Bratić and Vjekoslav Mario Dragun of the Faculty of Maritime Studies at the University of Split. Between April and September 2024, the team deployed monitoring equipment across ten locations in the city, capturing 154 observations in the port area and 66 along a busy road corridor. They measured fine particulate matter known as PM2.5, coarser particles called PM10, and carbon monoxide, while also logging traffic intensity. Environmental noise was measured in the road corridor, and meteorological variables such as wind speed were recorded to help interpret the results. The approach was deliberately screening-level: rather than running an expensive reference-grade network, the researchers relied on low-cost sensors to make a comparative assessment feasible.

The headline numbers are striking. Mean concentrations of PM2.5 and PM10 were higher in the port area than along the road corridor, at 14.77 and 18.25 micrograms per cubic meter respectively, compared with 11.64 and 14.70 micrograms per cubic meter at the roadside sites. That pattern fits the intuition that ships, with their large engines and sulfur-bearing fuels, should dominate particulate pollution near the waterfront. Yet the story flips for carbon monoxide, a gas tightly linked to combustion engines in vehicles: the road corridor recorded a mean of 5.20 parts per million, nearly double the port figure of 2.91 parts per million. Each transport mode, in other words, leaves its own chemical fingerprint.

But here is where the study becomes genuinely instructive. When the researchers ran formal statistical comparisons between sampling occasions at the two types of location, the differences in PM2.5, PM10 and carbon monoxide were not statistically significant, with p-values of 0.218, 0.227 and 0.505 respectively. The raw averages looked different, but the variability from one measurement session to the next was large enough that the differences could not be confidently distinguished from chance. This is a common and underappreciated problem in urban environmental monitoring: short-duration campaigns capture snapshots of air that is constantly churned by weather, traffic schedules and seasonal shifts, and single averages can mislead.

To dig deeper, the team turned to correlation and regression analysis, and this is where the signal emerged. The number of vessels in the port showed a statistically significant but weak association with PM10 concentrations, explaining only about 8 percent of the variance, with an R-squared of 0.082 and a p-value below 0.001. Vehicle counts, by contrast, were moderately associated with maximum road-noise levels, with an R-squared of 0.236 and a p-value below 0.001. These are modest effect sizes, and the authors are candid about what they mean: neither ships nor cars can be isolated as the dominant driver of pollution in a complex port-city atmosphere using this kind of data alone.

The most robust findings came from multivariable models that accounted for clustering in the data. Even after controlling for other factors, vessel count remained positively associated with both PM2.5 and PM10 in the port area, with p-values below 0.001. Wind speed told the opposite story: higher winds were consistently associated with lower particulate concentrations, a textbook demonstration of atmospheric dispersion at work. When the breeze picks up, it sweeps accumulated particles out of the urban bowl; when the air stagnates, pollution from every source piles up. Meteorology, the study suggests, can mask or amplify the contribution of any single traffic source, which is why the researchers treated weather variables as essential context rather than an afterthought.

One further technical detail deserves attention. The researchers estimated the coarse particle fraction, essentially the share of particulate mass made up of larger particles, and found it to be similar between the port and road environments. This is significant because particle size carries clues about origin. Coarse particles often come from mechanical processes such as brake wear, tire abrasion, resuspended road dust and cargo handling, while fine particles are more characteristic of combustion. A similar coarse fraction in both settings hints that non-exhaust and dust-related processes may be as important as tailpipe or stack emissions, a conclusion that echoes a growing body of literature on non-exhaust vehicle emissions and port dust.

Why does this matter beyond Split? The health stakes are high. Long-term exposure to traffic-related air pollution has been linked in systematic reviews to cardiovascular and respiratory disease, and PM2.5 in particular is implicated in heart disease through well-documented biological pathways. Environmental noise is not a benign companion either; pooled laboratory studies have shown that road, railway and aircraft noise disrupt sleep, and epidemiological work has connected chronic noise exposure to hypertension and other cardiovascular effects. In a port city, residents may be exposed to both stressors simultaneously, and the combined burden could exceed what either source alone would suggest. Studies of European port cities have begun to quantify these maritime health impacts, and the Split data add a Mediterranean data point to that emerging picture.

The study also carries a practical message about monitoring technology. Low-cost sensors have proliferated worldwide, offering cities the ability to deploy dense networks at a fraction of the cost of reference-grade instruments, but they come with well-known calibration challenges and accuracy limitations. The Split team argues that these devices are genuinely useful for comparative, screening-level assessments, the kind of work that identifies hotspots and guides where more rigorous measurement should follow. That is an important middle ground between doing nothing and committing to a full-scale regulatory monitoring network. For many cities in developing regions and smaller ports that lack institutional budgets, this tiered approach may be the only realistic path to evidence-based environmental policy.

Perhaps the deepest takeaway is methodological humility. The authors conclude that the results indicate overlapping rather than uniquely attributable transport-source effects. In plain terms, the air in a port city is a shared product of ships, vehicles, weather, geography and urban form, and no single measurement campaign can cleanly apportion blame. For city planners, that means interventions should be evaluated across both domains at once: shore-power connections and cleaner marine fuels for the harbor, low-emission zones and traffic management for the streets, and noise mapping that treats the waterfront and the roadway as one continuous acoustic environment. For researchers, it means integrated assessments like this one, imperfect as they are, point the way forward. Split’s experience suggests that the question is not whether ships or cars pollute more, but how two overlapping systems of mobility combine to shape the air and soundscape of the cities that host them, and how a modest array of affordable sensors can begin to untangle that knot.

Subject of Research: Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port city

Article Title: Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port-city environment

Article References: Integrated assessment of road and maritime traffic impacts on urban air quality and noise in a port-city environment. (n.d.). https://doi.org/10.1007/s10661-026-15986-8

Image Credits: AI Generated

DOI: 10.1007/s10661-026-15986-8

Keywords: air quality, port city, maritime emissions, road traffic, PM2.5, PM10, carbon monoxide, noise pollution, low-cost sensors, Split Croatia, environmental monitoring, shipping

The incident itself reads like a textbook medical emergency on the road. A 59-year-old man was driving alone when, according to the available information, a presumed medical event caused him to mount a traffic island and strike a traffic sign. The vehicle continued onto a service road before hitting a tree, and the driver was taken to hospital. Because of his medical condition, the standard field assessments that police normally use to evaluate drug or alcohol impairment could not be performed. Given his known cardiac history, however, officers suspected that medication might have played a role, and blood samples were drawn for toxicological analysis.

Laboratory screening using liquid chromatography-tandem mass spectrometry, the workhorse technique of modern forensic toxicology, detected four cardiovascular medications in the samples: amlodipine, bisoprolol, torasemide and valsartan. The first three were present at concentrations consistent with ordinary therapeutic use, so no further quantification was pursued. Valsartan, by contrast, produced strikingly strong signals, prompting the team to carry out a full quantitative determination using a standard-addition calibration method, a technique particularly well suited to unusual concentrations because known amounts of the analyte are added directly to the patient’s own sample.

The analytical work was rigorous by any standard. Each of three addition levels was processed in eight replicates, the mass spectrometer monitored two separate ion transitions to confirm the identity of the compound, and blank matrix samples showed no interfering signals. Because the concentration was so high, the sample had to be diluted tenfold before measurement. As an independent plausibility check, an external laboratory determined the concentration separately, arriving at 11.7 micrograms per millilitre against the primary laboratory’s 12.7 micrograms per millilitre, a close agreement that strongly supports the reliability of the reported figure.

What makes that number remarkable is the pharmacological context. Valsartan is an angiotensin II receptor antagonist, one of the widely prescribed sartan drugs, which lowers blood pressure by blocking the AT1 receptor. It is typically taken once daily at doses of 80 to 320 milligrams, and therapeutic plasma concentrations are generally considered to lie between 0.80 and 6.0 micrograms per millilitre. Pharmacokinetic studies have shown that single oral doses of 80, 160 and 320 milligrams produce mean blood concentrations of roughly 1.6, 3.8 and 6.4 micrograms per millilitre respectively, and even peak concentrations in healthy volunteers taking 320 milligrams under fasting conditions have reached only about 10.7 micrograms per millilitre. The driver’s measured value of 12.7 micrograms per millilitre therefore sits well above anything expected from normal therapeutic use.

Herein lies the forensic dilemma the authors set out to illuminate. For illicit drugs and many centrally acting medications, toxicology has robust, effect-related reference ranges: documented impairment can be correlated with measured concentrations, and recognised toxic and even lethal thresholds exist. For cardiovascular drugs, the picture is far murkier. Their primary action is on the circulatory system, and adverse effects such as hypotension, dizziness and light-headedness can occur even at correct doses. Establishing that such a medication caused unfitness to drive is difficult enough when blood concentrations fall within the therapeutic range; interpreting elevated concentrations is harder still, because no toxic concentration range for valsartan has ever been defined in the published literature.

The drug’s general safety profile compounds the interpretive problem. Valsartan is regarded as relatively safe even in massive overdose. The most frequently cited case report describes a woman who ingested an estimated 2,240 milligrams in a suicide attempt, suffering pronounced muscle cramps and marked hypotension, yet she improved within two days under supportive care, and no blood concentration was ever measured. Without documented concentration-effect data from overdose survivors, forensic experts have had essentially nothing to anchor their assessments when a driver tests positive for the drug. The new case provides exactly that anchor: a real-world concentration, verified twice, associated with a presumed medical emergency during active participation in road traffic.

The authors also emphasise a subtlety that single-drug toxicology often overlooks. Cardiac patients are rarely managed with one medication; they take combinations. In this case, the driver was also on amlodipine, a calcium channel blocker, bisoprolol, a beta-blocker of the sympatholytic class, and torasemide, a diuretic. When several blood-pressure-lowering agents act together, the heart’s compensatory capacity, its ability to maintain circulation if hypotension begins to develop, is substantially reduced. Bisoprolol in particular blunts the physiological responses that would normally counteract a sudden drop in blood pressure. The authors therefore argue that interactions with other antihypertensive agents and sympatholytic substances must be taken into account when evaluating valsartan findings in drivers, since the combined effect may produce impairment that no single drug concentration would predict.

On the basis of all available information, the team proposes a practical benchmark: valsartan concentrations exceeding 11 micrograms per millilitre should be regarded as elevated, and within the range observed in this case the potential relevance of valsartan intake during driving must be considered substantial. Given that the probability of significant adverse effects rises with concentration, the authors consider it plausible that valsartan was at least partly contributory to the presumed medical emergency behind the wheel. The prescribing information itself offers no help, since no specific studies have ever investigated the effects of valsartan on driving performance or the ability to operate machinery, even though dizziness and fatigue are recognised adverse effects of treatment.

The significance of the case extends well beyond one driver and one crashed car. Millions of people take sartans daily, and most of them drive, yet forensic guidelines for interpreting these drugs in traffic investigations have been almost entirely absent. By documenting a verified elevated concentration linked to an on-road medical incident, and by describing the analytical approach used to quantify it, the Hannover team has created a reference point that future forensic toxicologists can cite when valsartan appears in a traffic case. The authors suggest the incident may serve as a valuable reference for interpreting future traffic-related cases in which the possible involvement of valsartan is under forensic-toxicological assessment, a small but meaningful step toward closing one of the remaining gaps in the science of road safety.

Subject of Research: Forensic interpretation of elevated valsartan concentrations in a road traffic offender

Article Title: Differentiating therapeutic use and potential impairment in the forensic interpretation of valsartan concentrations in road traffic offenders

Article References: Dziadosz, M., Marquenie, L., Rosenberger, W., Klintschar, M., & Teske, J. (2026). Differentiating therapeutic use and potential impairment in the forensic interpretation of valsartan concentrations in road traffic offenders. International Journal of Legal Medicine. https://doi.org/10.1007/s00414-026-04008-4

Image Credits: AI Generated

DOI: 10.1007/s00414-026-04008-4

Keywords: valsartan, forensic toxicology, road traffic, blood pressure medication, LC-MS/MS, hypotension, driving impairment, pharmacokinetics, drug interactions, bisoprolol, International Journal of Legal Medicine, case report