Air quality in and around ships is governed by a variety of pollution sources that are unique for the shipping context. This makes the living and working conditions on ships substantially different from situations in cities or inside buildings. To gain insight into these differences, information about trends and absolute pollutant amounts on board ships is needed. However, the installation of reference instruments to monitor NO₂, NO, O₃, particulate matter and other environmental parameters is often not possible because of their size, weight or because of safety reasons. For that reason, more compact devices incorporating a variety of sensors are a good alternative. However, the use of such sensors is only possible when their behaviour and performance in a shipping context are well understood. To study this context, we were allowed to compare sensor-based measurements performed on a 36-year old ship dedicated to near shore operations with measurements of reference-grade instruments. Additional behavioural information of sensors is obtained by measuring campaigns organized on several inland ships. This contribution demonstrates that trends registered by gas and particulate matter sensors are reliable but that insufficient detection limits, higher noise, imperfect calibration and sensor errors result in some reliability constraints.

This study presents a fit-for-purpose lab and field evaluation of commercially available portable sensor systems for PM, NO₂, and/or BC. The main aim of the study is to identify portable sensor systems that are capable of reliably quantifying dynamic exposure gradients in urban environments. After an initial literature and market study resulting in 39 sensor systems, 10 sensor systems were ultimately purchased and benchmarked under laboratory and real-word conditions. We evaluated the comparability to reference analyzers, sensor precision, and sensitivity towards environmental confounders (temperature, humidity, and O₃). Moreover, we evaluated if the sensor accuracy can be improved by applying a lab or field calibration. Because the targeted application of the sensor systems under evaluation is mobile monitoring, we conducted a mobile field test in an urban environment to evaluate the GPS accuracy and potential impacts from vibrations on the resulting sensor signals. Results of the considered sensor systems indicate that out-of-the-box performance is relatively good for PM (R² = 0.68–0.9, Uexp = 16–66%, BSU = 0.1–0.7 µg/m³) and BC (R² = 0.82–0.83), but maturity of the tested NO₂ sensors is still low (R² = 0.38–0.55, Uexp = 111–614%) and additional efforts are needed in terms of signal noise and calibration, as proven by the performance after multilinear calibration (R² = 0.75–0.83, Uexp = 37–44%)). The horizontal accuracy of the built-in GPS was generally good, achieving <10 m accuracy for all sensor systems. More accurate and dynamic exposure assessments in contemporary urban environments are crucial to study real-world exposure of individuals and the resulting impacts on potential health endpoints. A greater availability of mobile monitoring systems capable of quantifying urban pollutant gradients will further boost this line of research.

Indoor air quality on board a 36-year-old ship has been characterized at several locations. The ship is dedicated to nearshore operations at the Belgian coast. This paper presents time-averaged and continuous-time measurements of several indoor pollutant concentrations such as NO₂, O₃, NO, CO, total volatile organic compounds (TVOC), polycyclic aromatic hydrocarbons (PAH), particulate matter PM_2.5 and PM₁₀, black carbon, and individual organic compounds. Time-averaged measurements suggest that the ships indoor air quality is sufficiently safe according to the prescribed occupational and nonoccupational health limits. However, the concentration of some indoor pollutants is comparable to that of the outdoor air of a large city such as Brussels, Belgium. Continuous-time analyses show that the temporal trends of indoor pollutant concentrations are inherently unstable. A large number of peaks or valleys are observed on a slowly fluctuating background. At some occasions, pollutant concentrations exceed the nonoccupational thresholds. Several pollutant peaks occur simultaneously, resulting in a pattern of peaks that is typical for a pollution source (e.g., exhaust gases entering the ships castle through the ventilation inlet, human presence, and bunkering). This study illustrates that multiparameter monitoring campaigns give valuable information about the behaviour of pollution sources, facilitating the definition of mitigation actions.

This paper describes the development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injection, is intended for use in large-scale IAQ assessments and employs an alternative tracer gas that is more adequate than the currently employed SF₆ and perfluorocarbons, and that can be co-captured and co-analyzed with commonly assessed VOCs by commercial passive IAQ-sampling. As it is based on passive sampling, the proposed TGT yields long-term integrated ACH values, and is thus indicated only for studies focused on characterizations based on average estimations rather than on analyses requiring fine temporal resolution. By means of literature study and lab experiments, decane-D₂₂ was selected as a suitable tracer substance. The selected tracer was shown not to adhere/absorb significantly to surfaces. A passive source of decane-D₂₂ was selected and optimized in lab, providing stable and repeatable emission rates unaffected by varying RH and ACH. An exponential prediction curve was derived for determining the source emission rate from the average room temperature. Moreover, a range of adequate levels of liquid tracer inside the source is suggested. A successful field test application for validation of the new TGT is also described.