Building façades can be affected by mould, algae and cyanobacteria which, through their dark pigments in the cells, can cause discoloration on the façade. These organisms are affected, among other things, by the availability of water and the air humidity. Discoloration generally does not cause any damage to the building, just presents as an aesthetic problem. There are various ways to prevent the emer-gence of these organisms. However research has shown that with the wrong methods used an opposite effect can be received. The methods that are used can also present a hazard for the environment. A field study of three different areas in Gävle, Sweden was carried out, here an ocu-lar inspection was made to identify buildings affected by discoloration. The areas studied were Lexe, Brynäs and Bomhus. In total 50 building facades with discolo-ration were found displayed on 25 different buildings. In Lexe and Bomhus several houses were found with facades that were classified as having the degree of discolo-ration “very”. The degree of discoloration was based on how widespread the discolo-ration was and how clearly it was visible to the naked eye. It was divided into three categories: “little”, “moderate” and “very” discoloured. A theory why these two areas were highly affected is the fact that they contain more vegetation compared to Brynäs. The proximity to water and roads was also considered to have had an effect. But it has not been possible to indicate how much these three aspects have affected. North and west façades were affected to a greater extent compared to south and east facades. A survey was distributed to everyone in the area. In the survey, respondents had to answer questions about discoloration. This to study how house owners feel about the problem. The response rate was low and only 33 responses were received. Hence, the survey not being as reliable as the sample size is small. But from the re-sponses that came in, it could be deduced that the majority wasn’t worried about di-scoloration. Even if they personally had been affected or currently dealt with the problem of discoloured building facades. Six pictures of building facades were also shown, this to find out how many of the respondents would take action to fix the facade in question. The results showed that the answer generally did not depend on the size and extent of the facade that was affected but rather how visible the discolo-ration was. Which mainly is affected by the colour of the facade and the type of org-anism. / Fasader kan drabbas av mögelsvampar, algbildning och cyanobakterier som genom sina mörka pigment i cellerna kan orsaka missfärgningar. Organismerna påverkas bland annat av vattentillgången och luftfuktigheten. Missfärgade fasader är generellt inget som skadar byggnaden utan endast ett estetiskt problem. Det finns olika sätt att förhindra tillkomsten av dessa organismer, dock kan dessa ha motsatt effekt om man behandlar mot fel organism. Metoderna som används kan även ha en stor nega-tiv effekt på miljön. En fältundersökning av tre områden i Gävle utfördes, här gjordes en okulär besikt-ning för att identifiera byggnader drabbade av missfärgningar. Områdena som un-dersöktes var Lexe, Brynäs samt Bomhus. Sammanlagt återfanns 50 fasader med missfärgningar utspridda på 25 olika hus. I Lexe och Bomhus hittades flera hus med fasader som klassades ha missfärgningsgraden “mycket”. Missfärgningsgraden baseras på missfärgningens utbredning samt hur visuellt tydligt den är och delades upp i ka-tegorierna “lite”,”måttligt och “mycket”. En teori är att dessa två områden har mera vegetation jämfört med Brynäs, även närheten till vattenmassor och större vägar an-ses ha påverkat. Men det har inte kunnat anvisats hur mycket dessa tre aspekter på-verkat. Nordliga och västliga fasader visade sig i större omfattning drabbas jämfört med sydliga- och östliga fasader. En enkät delades ut till samtliga i områdena i syfte att studera hur villaägare känner inför problemet med missfärgningar och algtillväxt. Svarsfrekvensen blev låg och endast 33 svar inkom. Därav är enkäten inte lika tillförlitlig då urvalet är litet. Av de svar som inkom kunde det utläsas att majoriteten inte var oroliga för problemet även om de just nu hade drabbade fasader eller tidigare haft. Sex bilder på fasader vi-sades även för att ta reda på hur många av respondenterna som skulle åtgärdat fasa-den i fråga. Resultatet blev att svaret generellt inte berodde på i vilken omfattning det vill säga utbredningen av fasaden som var drabbad utan mer hur synlig missfärg-ningen var. Vilket främst påverkas av fasadens färg och typen av organism som angri-pit fasaden.

The aim of this literature study was to investigate the effects of biofouling in the Baltic Sea. This was done to increase environmental awareness and understanding of the importance of a sustainable marine environment. A systematic search in selected databases resulted in the study being based on tio research articles. The overall results of the study show that biofouling demonstrate negative effects, but the effects are not fully understood to date and the focus is still on economic aspects. Furthermore, it was observed that the studied organizations are currently focused on greenhouse gas issues, but they have also been paying attention to biofouling problems in recent time. The literature study provides important insights into the effects of biofouling.