As a part of an ongoing study, we report measurements of air infiltration during winter conditions into two Decorated Farmhouses of Hälsingland designated as UNESCO World Heritage Sites. In winter these two-storied farmhouses are rarely heated, except for special occasions. In this measurement one farmhouse  was  unheated,  whereas  one  room  was  heated  for  a  brief  period  in  the  other  one.  The observed local mean ages of air measured with tracer gas techniques generally increase with height, both  locally  within  each  room  and  between  floors.  The  average  temperature  and  humidity  also increases from the first to the second floor. The indoor temperature follows the outdoor temperature with a time lag. The differences in water content between inside and outside air correlate with changes of the indoor relative humidity. The correlation is stronger for humidity increase than for humidity decrease, possibly due to moisture absorption by interior text.

A method to determine the rate of local transport into the indoor air of a substance originating from the construction frame of a building has been devised and tested. In particular we demonstrate that a tracer located outside the air and vapour barrier in the construction frame of an office building can be detected in varying concentrations in the office indoor air. The tracer may either diffuse directly or follow with outside air leaking through the barrier. Cor-recting for the local air change rate yields an apparent emission rate as an estimate of the rate of local transport from the construction frame to the indoor air. Our interpretation is that high-er apparent emission rates predominantly reflect higher local air leakage rates through the air and vapor barrier. This information could be useful for interpreting office worker complaints and for decisions on renovation options. The tracer techniques used in the study are also more generally applicable to convert measured concentrations of indoor substances into apparent emission rates. Emission rates are more indicative of the location of pollution sources and may therefore be useful in other investigations of polluted buildings.

The focus of this study is to assess the airflows in a school building built in 1963 in Gävle, Sweden, which is subject to energy conservation measures (ECMs) in a forthcoming renovation. Today, the school building is mainly ventilated by several mechanical ventilation systems, which are controlled by a constant air volume (CAV) strategy. Schedules and presence sensors impose a high operation mode during the day and a low operation mode at night, on weekends and on holidays. The homogeneous tracer gas emission method with passive sampling is used to measure the average local mean age of air (τ) during different operation modes. Temperature, relative humidity and CO₂ concentration are simultaneously measured. The calculated relative uncertainty for the average local mean age of air in every measured point is approx. ±20 %. The results during low operation mode show an average value of τ of approx. 8.51 h [corresponding to 0.12 air changes per hour (ACH)], where τ in various zones ranges between 2.55 and 16.37 h (indicating 0.06–0.39 ACH), which is related to the unintentional airflow in the school. The results during mixed operation mode show an average value of τ of approx. 4.60 h (0.22 ACH), where τ in various zones ranges between 2.00 and 8.98 h (0.11–0.50 ACH), which is related to both unintentional and intentional airflows in the school. Corridors, basement and attic rooms and entrances have lower τ compared to classrooms, offices and other rooms. High maximums of the CO₂ concentration in some rooms indicate an imbalance in the mechanical ventilation systems. During a regular school week of mixed operation, which includes both high and low operation modes, it is found that mainly the low operation modes show up in the results. The dynamics of the highly varying airflows in the building cannot be identified using the passive sampling technique.

The role of science as a provider of well-tested and trustworthy knowledgre in a sustainable society is discussed with respect to other social institutions: government and state bureaucracy, the market, the media and the public. In particular, societal pressures that threaten scientific endeavour are problematised with a slight bias towards examples from sustainability science. Global challenges of today transcend social institutions and therefore require novel modes of trans-institutional cooperation. Such modes of cooperation may produce unwanted clashes of institutional norms that imperil objective and mutually accepted norms need to be developed. The science policy for a democratic, sustainable society should strive for clear divisions among social institutions while encouraging suitable modes of cooperation to address global challenges to the sustainability of human life.

The number of people sensitized to the major birch pollen allergen Bet v 1 in industrialized countries is vast and still rising. The purpose of this study was to develop a method with sensitivity high enough to measure the Bet v 1 content of a few birch pollen grains without the interference of environmental factors such as diesel particles, ozone level, humidity, temperature and precipitation. Grains were collected from catkins at two locations in Sweden over a period of 5 years. Allergens were extracted over polytetrafluoroethylene (PTFE) filters and Bet v 1 quantification was made with a luminescence immunoassay. The average content of Bet v 1 was 3.6 ± 0.6 pg per pollen grain for samples collected in three different pollination seasons. This is the first in a series of controlled experiments on the release of the major allergen Bet v 1 from birch pollen grains.

Detta är bakgrunden till att små barn är fascinerande av att leka Titt-ut,men som alla föräldrar vet så försvinner den lekens lockelse när barnet blir äldre. Barn utvecklas snabbt i de yngre åren, vilket skapar både möjligheter och begränsningar för hur lärande i naturvetenskap och kemi uppstår i förskolan och grundskolan. Det finns många skäl till att kemirelaterade aktiviteter bör introduceras i de yngre åren och i det här kapitlet diskuteras några av dessa skäl ur ett kemididaktiskt perspektiv. Kapitlet är uppbyggt kring några av de betydande framsteg som gjorts i den utvecklingspsykologiska forskningen under de senaste tjugo åren (Gärdenfors, 2006). Idag vet vi ganska mycket om hur våra hjärnor fungerar och utvecklas. Insprängt i denna beskrivning kommer jag att reflektera kring hur detta skulle kunna påverka valet av innehåll när det gäller naturvetenskapligt lärande för yngre barn. På slutet sammanfattar jag tankarna om innehåll med ett speciellt fokus på kemi.

The ventilation and air leakage of a school building was investigated. Information was collected from the parameters of the mechanical ventilation system and from measurements of the local mean age of air using the homogeneous emission method. While the average local mean ages of air can be accurately measured by passive integrative samplers, the estimation of the average room specific air change rate by taking the inverse of the measured average local mean age of air did not give correct results. The main problem is that integrative sampling represents a linear averaging process that is inappropriate to capture the average of nonlinearly related properties. This problem is accentuated when the ventilation rates for different periods differ a lot. A simple computational model was developed to discuss the system behavior. A partial solution to the measurement problem is to actively sample the different populations of air change rates separately.

Den här boken samlar ett axplock av ämnesdidaktiska utmaningar inom matematik, naturvetenskap och teknik från lärare och forskare med anknytning till Högskolan i Gävle (HiG). Den röda tråden är en vilja att göra ämnena mer tillgängliga samt stimulera utveckling av undervisning och lärande i dessa ämnen.

Författarna till den här boken förenas av ett brinnande intresse för sina olika ämnen och en stark önskan att finna vägar till utveckling av undervisningen för att underlätta lärande och väcka nyfikenhet. Boken är skriven till dig som delar våra intressen. Vi hoppas att den ska inspirera till ytterligare utveckling av ämnesdidaktiken.

This study presents the ACH for ten apartments in naturally ventilated multifamily dwellings for two cases inlet vent manipulations: i) fully opened inlet vents; and ii) fully closed and taped inlet vents. Even with fully opened inlet vents the resulting ventilation is rather poor. The average ACH is 0.26±0.16 h-1. All apartments fall in the lower quartile in terms of ACH when compared to other multifamily dwellings in Sweden. A method using two different tracers A and B is presented that allow for measurement of the partial flow from the stairway zone and the partial flow from other pathways into the apartment. On the average 10-20% of the airflow into a typical apartment in a naturally ventilated multifamily dwelling seems to originate from the stairway zone when the inlet vents are fully opened. By closing and taping the inlet vents, the airtightness of the apartments have been investigated. The average direct leakage flow, i.e. not from the stairway zone, is 17 m3/h but the variation is large. Layout B seems to leak the most, followed by A and then C.