Sam-Erik Walker

Sam-Erik Walker holds an M.Sc. in Statistics and a B.Sc. in Computer Science from the University of Oslo.

He has over 30 years of experience developing and applying air pollution dispersion models for cities and urban areas and analysing air quality data using various numerical and statistical tools and methods. These include deterministic and probabilistic methods for model evaluation and validation, data assimilation, ensemble modelling, and data fusion to combine air quality observations with model results. He is one of the principal authors of several of the present models at NILU, including the urban air pollution dispersion model EPISODE.

He is also the leading developer behind the AirGAM trend and prediction model at NILU. This model enables the estimation of meteorology-adjusted long-term trends of air pollutants such as NO2, O3, PM, and VOCs at air quality stations in Norway and Europe. It has been used to quantify the effects of lockdowns during the recent COVID-19 pandemic and for estimating long-term trends for all EEA stations in Europe.

Recently, he developed the AirRisk model, a risk assessment model to quantify the risk or probability of exceeding limit values of NO2 and PM in connection with recent assessment studies in various Norwegian cities and urban areas, including Lørenskog, Drammen, and Oslo.

He actively disseminates scientific knowledge by writing reports and papers and regularly participates in scientific conferences. His primary motivation for working at NILU is to contribute to a cleaner world.