Publications

Influence of biomass burning and anthropogenic emissions on ozone, carbon monoxide and black carbon at the Mt. Cimone GAW-WMO global station (Italy, 2165 m a.s.l.).

Cristofanelli, P.; Fierli, F.; Marinoni, A.; Calzolari, F.; Duchi, R.; Burkhart, J.; Stohl, A.; Maione, M.; Arduini, J.; Bonasoni, P.

Inferring surface energy fluxes using drone data assimilation in large eddy simulations

Pirk, Norbert; Aalstad, Kristoffer; Westermann, Sebastian; Vatne, Astrid; Hove, Alouette van; Tallaksen, Lena Merete; Cassiani, Massimo; Katul, Gabriel G.

Spatially representative estimates of surface energy exchange from field measurements are required for improving and validating Earth system models and satellite remote sensing algorithms. The scarcity of flux measurements can limit understanding of ecohydrological responses to climate warming, especially in remote regions with limited infrastructure. Direct field measurements often apply the eddy covariance method on stationary towers, but recently, drone-based measurements of temperature, humidity, and wind speed have been suggested as a viable alternative to quantify the turbulent fluxes of sensible (H) and latent heat (LE). A data assimilation framework to infer uncertainty-aware surface flux estimates from sparse and noisy drone-based observations is developed and tested using a turbulence-resolving large eddy simulation (LES) as a forward model to connect surface fluxes to drone observations. The proposed framework explicitly represents the sequential collection of drone data, accounts for sensor noise, includes uncertainty in boundary and initial conditions, and jointly estimates the posterior distribution of a multivariate parameter space. Assuming typical flight times and observational errors of light-weight, multi-rotor drone systems, we first evaluate the information gain and performance of different ensemble-based data assimilation schemes in experiments with synthetically generated observations. It is shown that an iterative ensemble smoother outperforms both the non-iterative ensemble smoother and the particle batch smoother in the given problem, yielding well-calibrated posterior uncertainty with continuous ranked probability scores of 12 W m−2 for both H and LE, with standard deviations of 37 W m−2 (H) and 46 W m−2 (LE) for a 12 min vertical step profile by a single drone. Increasing flight times, using observations from multiple drones, and further narrowing the prior distributions of the initial conditions are viable for reducing the posterior spread. Sampling strategies prioritizing space–time exploration without temporal averaging, instead of hovering at fixed locations while averaging, enhance the non-linearities in the forward model and can lead to biased flux results with ensemble-based assimilation schemes. In a set of 18 real-world field experiments at two wetland sites in Norway, drone data assimilation estimates agree with independent eddy covariance estimates, with root mean square error values of 37 W m−2 (H), 52 W m−2 (LE), and 58 W m−2 (H+LE) and correlation coefficients of 0.90 (H), 0.40 (LE), and 0.83 (H+LE). While this comparison uses the simplifying assumptions of flux homogeneity, stationarity, and flat terrain, it is emphasized that the drone data assimilation framework is not confined to these assumptions and can thus readily be extended to more complex cases and other scalar fluxes, such as for trace gases in future studies.

Industrial emissions country profiles based on Eurostat data and the European pollution release and transfer register

Weydahl, Torleif

Indoor/outdoor particulate matter number and mass concentration in modern offices.

Chatoutsidou, S.E.; Ondracek, J.; Tesar, O.; Tørseth, K.; Zdimal, V.; Lazaridis, M.

Indoor wood burning and airborne particles. Model calculations for Oslo for the winter of 1998-1999. NILU OR

Slørdal, L.H.; Larssen, S.

Indoor organic films and dust as reservoirs of polychlorinated alkanes: Enrichment patterns and exposure implications

Ezker, Idoia Beloki; Yuan, Bo; Bohlin-Nizzetto, Pernilla; Li, Li; Borgen, Anders; Wang, Thanh

Indoor environments have shown to be a major source of human exposure of polychlorinated alkanes (PCAs), yet information on their distribution across indoor matrices and associated exposure pathways remains limited. PCAs, the main components in chlorinated paraffin mixtures, are widely used as flame retardants and plastic additives in numerous indoor consumer products and materials. This study quantified PCAs in paired indoor dust and indoor organic films (IOFs) from homes, offices, schools and gym sports halls (n = 41) in Sweden and assess their contribution to human exposure. Mean PCA concentrations in indoor dust were 7.3, 43.2, and 14.6 μg g−1 for ∑PCAs-C10–13, ∑PCAs-C14–17, and ∑PCAs-C18–30, respectively, while corresponding concentrations in IOFs were 38.2, 312, and 123 ng m−2. PCAs-C14–17 dominated both matrices, but IOFs showed an enrichment tendency towards longer-chain, higher-KOA PCAs, reflecting the less frequent cleaning and longer-term PCA accumulation in IOFs. IOF concentrations were particularly elevated in schools, and PCA variation across sites was influenced by differences in ventilation practices and building age. Dermal uptake was the dominant exposure pathway for children, with substantially estimated doses from IOFs, while adults show comparable dust dermal and dust ingestion exposures. PCA transformation products formed through hydroxylation, hydrolysis, and sulfation were also tentatively detected in both matrices. These findings highlight the importance of jointly assessing dust and IOFs to better characterize multipathway exposure to the diverse PCA mixture in indoor environments.

Indoor Environments - Sources for environmental contaminants & microplastic

Bohlin-Nizzetto, Pernilla

Indoor climate survey, A/S Norwegian Shell, Skøyen, Oslo. NILU OR

Braathen, O.-A.

Indoor and ambient air exposure of PAHs and fine particulate to women and children: health impacts in terms of morbidity, February 2002 - June 2005. NILU OR

Bartonova, A.; Sharma, M.

Indoor airborne VOC exposure and symptoms of allergy and asthma in children.

Choi, H.; Sundell, J.; Schmidbauer, N.; Spengler, J.; Bornehag, C.

Indoor air quality investigation sector E3-02. NILU OR

Tibi, N.; Sheikh Elhadadeen, T.

Abu Dhabi Municipality has chosen the Norwegian Institute for Air Research (NILU) to perform indoor air quality investigation for six buildings in sector E3-02 (one School, one Mosque, one commercial building and three Residential building).
The main goal of this task is to define the main pollutants that could be found in the buildings and to define the status of existing buildings with respect to indoor air quality.
The results of measurements that were conducted at different locations have shown that there was a wide mold growth in the duct of ventilation system due to poor maintenance in all studied buildings, also that carbon dioxide (CO2) and voltaic organic compound (VOC) are considered the main pollutants that could found and affect the indoor air quality in these buildings.

In most of tested locations, the CO2 concentration has exceeded the standard limit, the readings were very high in the school, mosque, and to a lesser extent in commercial building.

Indoor air quality in the Baroque Hall of the National Library in Prague - preliminary results. NILU PP

Lopez-Aparicio, S.; Stankiewicz, J.; Smolik, J.