Surface deposition is an important sink for tropospheric ozone. The rate of ozone deposition may be measured by measuring the downward flux of ozone in the atmospheric surface-layer. This thesis presents eddy correlation measurements of ozone fluxes, taken on eight days in August, 1994, at a grassland site located in the Lower Fraser Valley of British Columbia. Surface resistances to ozone deposition were calculated from the flux measurements. Much of the variability in measured surface resistances was found to be attributable to variations in ambient light levels and in the degree of moisture stress at the site. Measurements of surface resistance from this site agreed quite well with other measurements of ozone deposition to grassland surfaces. Measured surface resistances were compared to surface resistances calculated using the Wesely (1989) parameterization (W89) for surface resistance. W89 underestimated surface resistance, particularly in the mid afternoon and early evening. This was attributed to the model's neglect of the effects of water stress on stomatal resistance, as well as to a low value for resistance to ground surface deposition in the model. The eddy correlation fluxes were compared to ozone fluxes derived using an assumption of cospectral similarity between ozone and heat flux and to ozone fluxes measured using the variance method and the gradient method. The cospectral similarity method worked well and allowed a considerable relaxation of the sampling speed requirements of the eddy correlation method. The variance method produced biased flux measurements due to high frequency noise from the ozone sensor. Flux measurements using the gradient method had a great deal of scatter, due to inaccuracies in the measurement of gradients. / Arts, Faculty of / Geography, Department of / Graduate

Devido a sua grande amplitude altitudinal, o Parque Estadual da Serra do Mar - PESM - abriga fisionomias variadas da Floresta Ombrófila Densa, essas fisionomias se distribuem ao longo das cotas de níveis de maneira padronizada. Este trabalho busca avaliar a contribuição da deposição úmida, através de chuva, na distribuição dessas fisionomias. Para viabilizar o estudo nas diferentes altitudes foram escolhidos dois dos núcleos administrativos do PESM: o núcleo Picinguaba, o único entre eles a atingir o nível do mar, e o núcleo Santa Virgínia, que contempla as cotas mais altas de altitude e, conseqüentemente, as formações florestais a elas relacionadas. Observou-se em Picinguaba uma maior taxa de deposição de nitrogênio e carbono. A condutividade elétrica da água da chuva também foi maior em Picinguaba, evidenciando que outros elementos, como cloro, sódio, magnésio, entre outros, também são depositados em maiores taxas em Picinguaba. Assim, a variação nas fisionomias florestais ao longo do gradiente de altitude da serra do mar pode estar, em parte, associada às diferentes taxas de deposição atmosférica / Due its altitudinal amplitude, the Serra do Mar State Park (PESM), shelters a variety of physiognomies of the Dense Ombrophylous Forest, such physiognomies are distributed along the level quota in a standard way. This work aims to evaluate the contribution of the moist deposition through the rain, in the distribution of these physiognomies. In order do make the study in different altitudes possible, two PESM administrative nucleus were chosen: the Picinguaba nucleus, the only one among these ones that reaches the sea level, and the Santa Virginia nucleus which contemplates the highest quotas of altitude and consequentially, the forest formations related to them. It was observed in Picinguaba a lower rate of nitrogen and carbon deposition. The electrical conductivity of the rain water was higher in Picinguaba, putting into evidence that other elements, such as chlorine, sodium, magnesium, and others are also deposited in higher rates in Picinguaba. Thus, the variation in the forest physiognomies along the altitudinal gradient of Serra do Mar could be, in part, related to the different rates of the atmospheric deposition

Atmospheric nutrient loading and transport though precipitation and dry deposition is one of the least understood yet one of the most important pathways of nutrient transport into many lakes. These nutrients, phosphorus and nitrogen, are essential for aquatic life and often play major roles in algae blooms that occur in lakes and reservoirs. Often heavy algal growth intensifies a variety of water quality problems. Utah Lake may be even more susceptible to atmospheric deposition due to its large surface area to volume ratio and proximity to Great Basin dust sources. In this study, eight months of atmospheric deposition data were collected and analyzed from five locations near Utah Lake. Geospatial maps were created to show the temporal distribution of phosphorus and nitrogen. Evaluation of the atmospheric deposition results indicate that between 8 to 350 tons of total phosphorus and 46 to 460 tons of dissolved inorganic nitrogen were deposited onto the surface of Utah Lake over an eight-month period. Both estimates were based on assuming that the deposition decreased exponentially from the sampling station to the middle of the lake. The large difference results from using only samples with no visible particles or insects present to give the low estimate and all samples to give the high estimate. These nutrient loading values are very significant in that it has been estimated that only about 17 tons year-1 of phosphorus and about 200 tons year-1 of nitrogen are needed to support a eutrophic level of algal growth in Utah Lake. Atmospheric deposition was found to be a major contributor in providing a eutrophic nutrient load to Utah Lake. Further, it is likely that the actual deposition loading is much higher than 8 tons per 8 months thus indicating that deposition alone adds a eutrophic phosphorus loading to the lake. Since conditions are similar in much of the Great Basin and other areas of Western United States, this seems to be a very significant finding relative to nutrient evaluation and feasible management scenarios. The results also indicate that one might expect to see more cyanobacteria blooms (Harmful Algal Blooms) in shallow ponds in this area if atmospheric deposition is the main source of nutrients, since N to P ratios are low and thus more situations arise where a shortage of ionic nitrogen favors these nitrogen-fixing cyanobacteria.

Anthropogenic reactive nitrogen is emitted into the atmosphere from fossil fuel combustion (nitrogen oxides) and agricultural activities (nitrogen oxides and ammonia). Nitrogen oxide emissions have long been controlled for their role in ambient air pollution and human health effects. However, reactive nitrogen deposition is less understood even though it can play a significant role in altering biodiversity, impairing ecosystem and biogeochemical function and degrading cultural artifacts. Although nitrogen deposition is a natural part of biogeochemical cycling, many ecosystems across the United States are at risk of exceeding the critical nitrogen deposition load. While nitrogen oxides are routinely measured in urban areas, far less is known in non-urban landscapes where ecosystems may be especially sensitive. Regional chemical transport models have been used to predict the impacts of ambient reactive nitrogen deposition in non-urban areas, but models have difficulty simulating reactive nitrogen due to poorly quantified emissions, especially from the agricultural sector. My research explores the speciated deposition of reactive nitrogen through monitoring and modeling in the unique field setting of the 150 mile Columbia River Gorge (CRG) located along the border of Oregon and Washington. This site is ideally suited for this investigation due to the large sources of reactive nitrogen at either end of the CRG and unique seasonally driven channel wind flow. Seasonally driven wind allowed us to look at the reactive nitrogen emissions flowing through the CRG to assess ambient the reactive nitrogen partitioning and deposition gradient. Using data collected by the United States Forest Service to control ambient haze in the CRG and our co-located nitrogen oxides (NOx) gas analyzer, we first characterized the influence of seasonal, bimodal wind distributions on the spatial distribution of reactive nitrogen. We found that during winter months with predominantly easterly winds, particulate nitrate and ammonium and gas-phase nitrogen dioxide levels create a gradient from the eastern end to the western end. Particulate nitrate and sulfate mass concentrations influence the CRG gradient during summer months with predominantly western winds. We also found that the magnitude of the impact from east is greater than the magnitude of impact from the west. When we compared our observations to regional chemistry transport models, we found that models are significantly under-predicting levels of reactive nitrogen in the CRG. This bias is not isolated to a single station within the Gorge, but throughout the whole Columbia Basin. Our results indicate that there are under-represented emissions in the region leading to this bias. Partly due to the bias in reactive N gas-phase species in the CRG, regional models have been underestimating the impact of gas-phase reactive N on dry N deposition. We conducted field studies at two sites within the CRG monitoring reactive nitrogen species (nitric oxide, nitrogen dioxide, ammonia, nitric acid, particulate nitrate, particulate ammonium, and particulate sulfate) as well as ozone and meteorological parameters. These measurements allowed us to conduct the first comprehensive analysis of reactive nitrogen partitioning and deposition in the CRG. Through our measurements, we found reactive nitrogen was higher in the spring than the summer. We found concentrations ranging from 0-15 ppbv ammonia, 0-7 ppbv nitric acid, 0-2 µg/m3 ammonium nitrate and 0-1 µg/m3 ammonium sulfate at the sites. Through the measurements of all these species, we evaluated the limiting gas-phase precursor to inorganic nitrogen particle formation. In the springtime, ammonia limits the formation of particulate reactive nitrogen; while in the summer, nitric acid and oxidized sulfur limit the formation of inorganic nitrogen particles. This suggests that there may be more sources of ammonia in the spring with fertilizer application or perhaps reactive nitrogen reservoirs are renoxified through thermal dissociation during warmer summer months. Our estimated deposition from gas and particle phase reactive nitrogen ranged from 0-0.14 kg N/ha per day. We also found that gas-phase reactive nitrogen plays the largest role in dry N deposition in the CRG with particle-phase contributing less than 15% of total dry N deposition. These results are important for land managers to understand the total impact of reactive nitrogen to non-urban areas. This research can inform mitigation strategies for haze formation, identify the major species and sources involved in dry N deposition and assess the potential impacts to ecosystems and cultural artifacts.

Thesis (M.S.)--University of North Carolina, 2004. / Includes bibliographical references (leaves : [94]-100).

Over-enrichment of nutrients in coastal waters has been a growing problem as population growth has enhanced agricultural and industrial processes. Enhanced nitrogen (N) fluxes from land to coast continue to be the result of over fertilization and pollution deposition. This over-enrichment of nutrients has led to eutrophication and hypoxic conditions in coastal environments. This study was conducted along the Gulf of Mexico, through the state of Texas, in order to quantify all agricultural and industrial sources of N in a region which contains a large precipitation gradient, three major metropolitan areas, and one of the top livestock industries in the United States. Nitrogen inputs from fertilizer, livestock, crop fixation, and oxidized deposition from both dry and wet atmospheric processes were quantified and compiled into a Texas Anthropogenic N Budget (TX-ANB). In addition, comparisons and regional enhancements were made to the Net Anthropogenic Nitrogen Input dataset (NANI toolbox), which is a national dataset developed at Cornell University by Hong et al. [2011]. These enhancements ultimately will help understand the full pathways of anthropogenic influences on coastal systems in a regional setting. All three datasets (NANI, NANI Regional, and TX-ANB) indicate agriculture to be the primary contributor to the N cycle in Texas, with TX-ANB showing 38% of inputs from fertilizer, 37% of inputs from livestock, and 2% of inputs from legumes. N input due to atmospheric deposition of oxidized N clearly highlights urban areas, indicating a strong influence of urbanization on the N cycle due to anthropogenic impacts; 23% of N input in Texas is the result of deposition of oxidized N. Quantification of inputs spatially indicates a strong enhancement of N from human influence in the coastal plain where nutrient export is heightened by major storm events. This enhancement of N along a coastal drainage area will likely have a negative impact on downstream environments. / text

Perfluoroalkyl substances (PFASs) are man-made chemicals. Their unique properties make them beneficial for a wide range of industrial and consumer product applications, such as in aqueous film forming foam (AFFF), durable water repellent clothing, hydraulic oils and food packaging materials. Perfluoroalkyl acids (PFAAs), a class of PFASs, are highly persistent in the environment, and long chain PFAAs are bioaccumulative and toxic. International regulation and voluntary actions by the industry have been implemented and led to a recent reduction of primary emissions of PFAAs to the environment. However, point sources such as AFFF training sites as well as diffuse sources continue to contaminate water bodies, soil and biota. Reducing environmental pollution with PFAAs has therefore become a regulatory priority. Designing successful measures to reduce the PFAA contamination requires an understanding of the sources, transport and fate of PFAAs in the environment. Four scientific publications are included in this PhD thesis, which aimed at increasing the holistic understanding of the fate of PFAAs in aquatic systems. This was achieved by chemical trace analysis combined with mass balance modeling. The following topics were covered: Dispersion and fate of PFAAs from an AFFF-impacted site (Paper I), recirculation of PFAAs in the aquatic environment with focus on waste water treatment plants (WWTPs, Paper II), mass balance of PFAAs in the Baltic Sea (Paper III) and transport and fate of PFAAs in two pristine boreal stream catchments (Paper IV). Results from Paper I showed that AFFF-impacted sites at a former military airfield, which was abandoned for more than 30 years, continue to be point sources of PFAAs to recipients. The sum of PFAAs in the ground water and surface waters ranged from 740 to 51000 ng L-1 and &lt;0.5 to 79 ng L-1, respectively. PFOS in muscle tissue of European perch from a nearby lake ranged from 77 to 370 ng g-1 wet weight, representing among the highest values reported worldwide for fish muscle. In Paper II the relative importance of environmental recirculation of PFAAs versus new releases from the technosphere was investigated for PFAAs in WWTP influents. It was shown that tap water can be an important source of PFAAs to WWTPs in areas with elevated environmental levels. This needs to be taken into account when calculating emissions via WWTP effluents. PFAA mass balances over the WWTPs suggested that PFHxA and PFOA were formed from precursor compounds within the plants. Assembled PFAA mass balances for the Baltic Sea (Paper III) showed that river inflow and atmospheric deposition were the dominant input pathways, while wastewater treatment plant (WWTP) effluents discharging directly into the Baltic Sea made a minor contribution. The inputs of PFAAs were estimated to be higher than the outputs, suggesting a current increase of the PFAA inventory in the Baltic Sea. Also the mass balance study of PFAAs in two remote stream catchments presented in Paper IV revealed that inputs dominated over outputs for both catchments, indicating that a considerable portion of the PFAAs deposited from the atmosphere is retained in soil or in deep ground water and may be released to surface and marine water environments in the future / Perfluoralkilne tvari (PFASs) su umjetne kemikalije. Zbog svojih jedinstvenih svojstava široko su primjenjive u industriji i izradi proizvoda krajnje potrošnje kao što su pjena za gašenje požara (AFFF), vodootporna odjeća, hidraulična ulja i pakiranja za hranu. Perfluoralkilna kiselina (PFAAs) iz skupine perfluoralkilnih tvari iznimno je dugotrajna u okolišu, a dugolančane PFAAs su bioakumulativne i otrovne. Poduzeta međunarodna regulativa i dobrovoljne akcije vodile su nedavno smanjenoj primarnoj emisiji PFAAs u okoliš. Unatoč tome, primarni izvori, kao što su mjesta na kojima se provode treninzi za gašenje požara i difuzni izvori i dalje zagađuju vode, tlo i biotu. Zbog toga, smanjenje onečišćenja okoliša izazvanog PFAAs predstavlja regulatorni prioritet. Stvaranje uspješnih mjera kojima bi se smanjilo onečišćenje izazvano PFAAs zahtjeva razumijevanje izvora, prijenosa i sudbine tih tvari u okolišu. U ovaj doktorat uključena su četiri znanstvena članka kojima je cilj povećati sveukupno razumijevanje sudbine PFAAs u vodenim sustavima. To je postignuto kemijskom analizom elemenata u tragovima u kombinaciji s modeliranjem masene ravnoteže. Obrađene su sljedeće teme: Širenje i sudbina PFAAs na područjima zahvaćenim AFFF (Članak I), ponovna cirkulacija PFAAs u vodenom okolišu s naglaskom na postrojenja za pročišćavanje otpadnih voda (Članak II), masena ravnoteža PFAAs u Baltičkom moru (Članak III) te prijenos i sudbina PFAAs u dva udaljena sjeverna vodena toka (Članak IV).   Rezultati iz Članka I pokazali su da su područja zahvaćena AFFF na bivšem vojnom aerodromu napuštenom prije 30 godina i dalje je glavni izvor PFAA zagadenja okolisa. Zbroj PFAAs u podzemnim i površinskim vodama kreće se u rasponu od 740 do 51000 ng L-1 i &lt;0.5 do 79 ng L-1. PFOS u mišićnom tkivu grgeča iz obližnjeg jezera kreće se od 77 do 370 ng g-1 mokre težine, predstavljajući jednu od najviših vrijednosti u svijetu za riblje mišiće. Članak II istražuje relativnu važnost ponovne cirkulacije PFAAs imajući na umu novu emisiju PFAAs iz tehnosfere u postrojenjima za pročišćavanje otpadnih voda. Cirkulacija/kruženje u okolišu može se pojaviti kada PFAAs iz sustava pitke voda (rijeka, bunara i jezera) odlaze u otpadne vode. Prikazano je kako voda iz slavine može biti važan izvor PFAAs sustavima za pročišćavanje otpadnih voda u područjima s povišenim razinama zaštite okoliša. To se treba uzeti u obzir pri računanju emisije putem strojeva koji se koriste za pročišćenje otpadnih voda. Masena ravnoteža PFAA u postrojenjima za pročišćavanje otpadnih voda upućuje na to da su PFHxA i PFOA stvoreni kao prethodni spojevi unutar postrojenja. Prikupljene masene ravnoteže PFAA za Baltičko more (Članak III) pokazale su da su pritoke rijeka i atmosfersko taloženje dominantni ulazni putovi, dok postrojenja za pročišćenje otpadnih voda pridonose tek u manjoj mjeri. Ulaz PFAAs je procijenjen višim od izlaza, što objašnjava trenutno povećanje sadržaja PFAA u Baltičkom moru. Masena ravnoteža PFAAs u dva udaljena riječna toka predstavljena u Članku IV otkriva da ulaz dominira nad izlazom za oba riječna toka, što upućuje na značajan udio PFAAs koji je iz atmosfere zadržan u tlu ili podzemnim vodama te može biti ispušten u područja površinskih voda i mora. / Perfluorerade alkylsyror (PFAA) är kemikalier som är producerade av människan. Deras unika egenskaper gör att de kan användas i många olika industriella applikationer. PFAAs används i brandsläckningsskum, vattenavvisande kläder, hydrauliska oljor och matförpackningar. PFAAs har visat sig vara persistenta i miljön, och långkedjiga PFAA-homologer har visat sig vara bioackumulerbara samt ha en toxisk verkan. Reglering på internationell nivå tillsammans med initiativ från industrin har lett till minskning av direkta utsläpp. Punktkällor som brandövningsplatser samt andra diffusa källor fortsätter att förorena omgivande vattendrag, jordlager och fauna. Den utbredda föroreningen av PFAAs har därför blivit prioriterad för reglering. För att förstå utsläppen av PFAAs i miljön, hur de transporteras samt deras öde i miljön, är det viktigt att utföra studier som belyser dessa områden.   Denna doktorsavhandling inkluderar fyra vetenskapliga publikationer. Syftet med de underliggande studierna var att öka den holistiska förståelsen av PFAAs rörelse i akvatiska system. Studierna gjordes genom att kombinera kemiska analysmetoder med modellering. Följande  studier genomfördes; Transport och spridning av PFAAs från en brandövningsplats (Paper I), recyklering av PFAAs i den akvatiska miljön med fokus på vattenreningsverk (Paper II), massbalans av PFAAs i Östersjön (Paper III), transport och öde av PFAAs i två pristina vattendrag (Paper IV).   Resultat från (Paper I) visade att brandövningsplatser vid en flygplats som inte har varit i bruk i mer än 30 år, fortfarande är punktkällor av PFAAs till omgivande vattendrag. Summan av PFAAs koncentrationer i grundvattnet och ytvattnet sträckte sig från 740 till 51000 ng L-1 och &lt;0.5 till 79 ng L-1 i respektive vattendrag. Koncentrationen av PFOS i muskelvävnad från  aborre i en av sjöarna var 77 till 370 ng g-1 våtvikt. Dessa värden representerar några av de högsta uppmätta koncentrationerna i världen. I Paper II testades betydelsen av PFAAs från recirkulering i miljön i jämförelse med nya utsläpp från teknosfären. Recirkulering av PFAAs i miljön kan förekomma då PFAAs i inkommande vatten till reningsverk kommer från dricksvatten. Denna studie visar att dricksvatten kan vara en påtaglig källa av PFAAs till vattenreningsverk i områden med förhöjda halter av PFAAs i miljön. Detta måste tas hänsyn till när man beräknar emissioner med utgående vatten från vattenreningsverk. Massbalanser av PFAAs i reningsverken visar att PFHxA och PFOA bildades av prekursorämnen i vattenreningsverken. I Paper III beräknades massbalanserna av PFAAs i Östersjön, beräkningarna visar att floder och atmosfärisk nedebörd var de viktigaste källorna medan utsläppen från vattenreningsverk var markant lägre. Importen av PFAAs estimerades vara högre än exporten, varför vi tror att PFAAs mängden I Östersjön kommer att öka över tid. Vidare gjordes en mass balans av PFAAs i två avlägsna avrinningsområden (Paper IV). Resultaten visar att importen av PFAAs dominerar över exporten från båda avrinningsområdena. Detta indikerar att en stor del av PFAAs som kommer ner via nederbörd kommer att ansamlas i jorden eller i grundvattnet. Dessa PFAAs kan vid senare tillfälle komma att släppas ut till floder som rinner ut i marina vatten. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p><p> </p>

Tests were conducted for 71 pesticides in weekly bulk (wet + dry) deposition samples collected from May 25 to September 21 over two years at two sites in the City of Winnipeg, Canada. Twenty-one pesticides and their metabolites were detected in this study and 99% of samples collected contained mixtures of two or more pesticides. Malathion and glyphosate were the largest contributors to bulk deposition in 2010 and 2011, respectively. A second study examined the mineralization of 2,4-D and 17β-estradiol using a novel in-field soil microcosm study and a series of laboratory experiments under different temperature incubations. Results indicated that temperature fluctuations do not greatly affect the amount or rate of mineralization relative to the traditionally constant laboratory incubations of 20°C; however long-term freezing of soil reduced potential mineralization over time. This research advances scientific knowledge of agri-chemical fate and provides data for strengthening current environmental policy analysis in Canada.

No description available.

Mikroskräp, vilket är partiklar mindre än 5 mm, kan exempelvis bestå av textilfibrer, plast-, gummi-, väg- och förbränningspartiklar. Partiklarna sprids i miljön på grund av mänskliga aktiviteter och problemet är internationellt uppmärksammat, speciellt för mikroplaster där många vetenskapliga studier har gjorts. Det är känt att mikroskräp kan vara problematiskt då partiklarna dels kan bestå av toxiska ämnen, de kan även föra med sig skadliga ämnen via adsorption till recipient vilket kan påverka växter och djur negativt. Slutligen kan djur missta partiklarna som föda vilket kan leda till kvävning och svält. Studier på mikroskräp utförs för att öka kunskapen om bland annat spridningen och hur omgivningen påverkas av de små skräppartiklarna. Hittills har få studier gjorts på mikroskräpförekomster i urbana områden. För att öka den kunskapen om förekomsten av mikroskräp i den urbana miljön har en studie genomförts i Luleå där syftet var att undersöka typ och kvantitet mikroskräp som förekommer i den urbana miljön. Olika områdestyper har granskats och dessa är; flerfamiljshusområde, villaområde, centrum/park, centrum/trafik, handelsområde, industriområde och ett icke-urbant område. Storleks- och färgvariationer samt skillnader mellan områdestypernas skräpförekomster skulle också studeras. Prover från alla områdestyper togs under våren 2018 från orörd snö där föroreningar ackumulerats under vinterhalvåret. Med orörd snö menas sådan snö som är opåverkad från yttre faktorer som exempelvis nedtrampning eller skottning. Den smälta snön filtrerades genom två filter som hade porstorlekarna 300 µm och 50 µm. Även analyser av pH, konduktivitet, suspenderat material och glödgningsförlust gjordes på prov från alla områden. Filtren analyserades i stereomikroskop med en förstoring på cirka 40 gånger. Antalet naturliga fibrer, plastfibrer, plastpartiklar och svarta partiklar analyserades från alla filter och färgen hos fibrerna och plastpartiklarna noterades. De svarta partiklarna delades upp i väg-, eller förbränningspartiklar, gummipartiklar och sfäriska förbränningspartiklar. Resultaten visade att det förekommer mikroskräppartiklar i den urbana miljön. Det var främst svarta partiklar som detekterades, antalet uppgick till hundratals upp mot tusentals partiklar per liter. Antalet detekterade fibrer från urbana områden varierade mellan ca 150-200 stycken per liter medan det detekterats ca 40 fibrer per liter från det rurala området. Förekomsten av plastpartiklar från de olika områdestyperna var mer sällsynt då det endast detekterades från tre av sju provtagningsområden, antalet uppgick till 5-11 partiklar per liter. Det detekterades fler partiklar i den mindre storleksfraktionen, 50–300 µm i jämförelse med den större &gt;300 µm. Fibrernas färger varierade mycket från varje provtagningsplats men vanliga färger var svart, blå och transparant. Flest partiklar detekterades i prov från de urbana områdestyperna centrum park, centrum trafik och från handelsområdet. Minst antal partiklar detekterades i det icke-urbana området som hade minst urban påverkan. Slutsatser som drogs från studien var att det förekommer och sprids mikroskräp i den urbana miljön. Områden som har större exponering av människor och trafik har också ett högre antal mikroskräppartiklar per liter samt per kvadratmeter och dag. Genom att undersöka förekomsten av mikroskräp i fler städer samt att använda ytterligare karaktäriserande metoder för att bestämma vilken typ av partikel som detekterats så hade det bidragit till ökad kunskap om förekomsten och spridningen av mikroskräp i urbana miljöer. / Micro litter, which are particles less than 5 mm, can include, for example textile- and plastic fibres, plastic-, rubber-, road-, and combustion particles. The particles are present and widespread in the environment due to human activities and the problem is internationally noted. Especially for microplastics, which is a part of micro litter, where many scientific studies are made. It is known that micro litter particles could both consist of and bring harmful elements via adsorption to the recipient where animals and plants could be adversely affected. The micro litter could also be mistaken of being food by animals. Micro litter studies are made to increase the knowledge about the occurrence, effects and fate of the small particles. So far, only a few studies are made on the occurrence of micro litter in urban areas.To increase the knowledge of the occurrence of microliter in the urban environment, a study has been carried out in Luleå (north of Sweden) where the purpose was to investigate the type and quantity of micro litter that occurs in the urban environment. Different types of areas have been studied, these are; an apartment area, an area of villas, a park and an area with a lot of traffic in the city centre, commercial area, industrial area and a rural undeveloped area. Differences in particle sizes and colour, together with the variations between the studied areas was also determined. All different studied areas were sampled during spring 2018 of untouched snow, which means undisturbed snow (not e.g. shovelled snow). Meltwater from the snow was filtrated through two filters with mesh sizes of 300 µm and 50 µm. Analysis of pH, conductivity, suspended solids and loss of ignition was also made. The filters were analysed in a stereo microscope with a magnification of around 40 times. The number of fibres, both plastic and naturally occurring, plastic particles and black particles were counted from all filters. The colour of the fibres and plastic particles were also noted. The black particles were divided between road or combustion particles, rubber particles and spherical combustion particles.The results showed that micro litter particles occur in the urban environment. The most common type of discovered micro litter was black particles, hundred up to thousands of particles per litre was detected. The number of detected fibres from urban areas varied between 150-200 per litre, while in the rural area, 40 fibres per litre were detected. The occurrence of plastic particles were more rare in the different sampling locations, since it only was detected in three of seven sampling areas and varied between 5-11 particles per litre. In the smaller particle fraction, 50– 300 µm, a higher number of particles were detected in comparison with the larger fraction (&gt;300 µm). A large variation was seen between colours of the fibres, the most common ones were black, blue and transparent. The largest amount of micro litter was detected in the urban areas, in the park and the area with traffic in the city centre and from the commercial area. Least particles were detected in the rural area which had the least urban impact. Conclusions drawn from the study were that micro litter occurs and are widespread in the urban environment. Areas with high exposure to humans and traffic also have higher amounts of micro litter particles per litre and per square meter and day.By investigating the presence of micro litter in more cities and using additional characterizing methods for determining the type of particles that have been detected, it would have contributed to increasing knowledge about the occurrence and spread of micro litter in urban environments.