Indoor sources of air pollution generate a large fraction of overall human exposure to airborne pollutants. Materials used in buildings have been shown to be a major contributor to indoor air pollution, with green building agencies setting guidelines limiting their primary emissions. However, such guidelines neglect secondary emissions resulting from chemistry occurring in indoor spaces. Furthermore, limited knowledge exists regarding ozone reactions and green building materials. This study focuses on the primary aldehyde emissions, ozone deposition velocity, and secondary emissions from three green building materials: recycled carpet, sustainable ceiling tile, and low-VOC paint and primer on recycled drywall. Ozone reactions resulted in secondary aldehyde emissions ranging from no increased secondary emissions to 237 µg m-2 hr-1. Modeling results suggest that these emissions can cause concentration increases beyond odor thresholds. / text

In this thesis empirical relationships and modeling tools are used to describe the relationship between human activities and meso- and large scale riverine N fluxes from land to sea. On a large scale Paper I showed that by only having knowledge about human population size and runoff one can estimate the riverine export of DIN (r2= 0.76). In Paper II we included two other important anthropogenic N inputs, i.e. atmospheric deposition and primary emission (PE) from animals. In most of the catchments the PE from animals were larger than the PE from humans. Hence, development of livestock is important and increased animal protein consumption by humans might increase the riverine N export. Scenario analysis (Paper II) show that climate change is expected to both decrease and increase the riverine N export depending on which part of the catchment is modeled. In the southern and eastern parts of the Baltic Sea catchment there is large potential for N reductions from point sources (Papers III & V). The diffuse sources are more difficult to decrease and a reduction of mineral fertilizer does not always lead to reduced N loadings because the agricultural systems can buffer even a slight surplus (Paper III). There is inertia in the catchments which can be seen in for example in the northern part of the catchment. Here atmospheric N deposition is almost as high as in the southern part but the nitrogen flux from these rivers is not elevated. These northern river catchments have N exports of the same magnitude as the natural background (Paper IV), indicating that the atmospheric N deposition is retained in the system and probably taken up by N limited boreal forests. However, important reductions can be achieved in the agricultural sector by detailed management of the planted land and animal manure. The highest sensitivity is in catchments with high animal density and high specific discharge, primarily draining to Kattegat and Danish Straits (Paper II & IV). / At the time of doctoral dissertation the following publications were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript