Svenske arbeider om inneklima i skoler og allergi og/eller astma
(Finn Levy)
Almqvist C., Larsson P.H., Egmar A.C., Hedren M., Malmberg P., Wickman M. (1999):
School as a risk environment for children allergic to cats and a site for transfer of cat allergen to homes. Journal of Allergy & Clinical Immunology. 103(6):1012-17
Almqvist et al., performed a study to airborne and clothes levels of cat allergen (Fel d 1) at schools and in homes with or without cats from children attending classes with many (>25%) or few (<10%) cat owners and homes with or without cats. The median airborne cat allergen concentration in classes with many cat owners was significantly higher than those found in the homes of non-cat owners (P <.001) but lower than that found in homes with cats (P <.001). Allergen levels in non-cat owners' clothes increased after a school day (P <.001). Non-cat owners in classes with many cat owners had higher levels of mattress-bound cat allergen (P =.01). The results indicate significant exposure to cat allergen at school by the spread through clothing from homes with cats to classrooms. There the allergen is dispersed in air and contaminates the clothes of children without cats. The allergen levels in non-cat owners' homes correlate with exposure to cat allergen at school.
Berge M., Munir A. K., Dreborg S. (1998),:
Concentrations of cat (Fel d 1), dog (Can f 1) and mite (Der f 1 and Der p 1) allergens in the clothing and school environment of Swedish schoolchildren with and without pets at home. Pediatric Allergy and Immunology, Volume 9(1), 25-30
Berge et al., studied the levels of Fel d 1, Can f 1, Der p 1 and Der f 1 in dust from the classrooms and clothes of children in a Swedish school. Thirty-one children were selected in four classes, forming three groups: cat owners, dog owners and children without a cat or dog at home. Cat and dog allergens were detected in all 57 samples from clothes and classrooms. Both cat and dog allergens were present in higher concentrations in dust from curtains than from floors and shelves. The dog owners had significantly higher concentrations of Can f 1 (8434 ng/g fine dust) in their clothes than children without cat or dog (2742 ng/g, p<0.05). The cat owners had significantly higher levels of Fel d 1 (1105 ng/g) in their clothes than for all children without a cat at home (345 ng/g, p<0.05). Mite allergen Der f 1 was detected in low concentrations in 6 out of 48 and Der p 1 in 5 out of 46 samples investigated. The conclusion was that the results supported the hypothesis that cat and dog owners bring allergens to public areas in their clothes and support other studies showing that textiles and upholstered furniture function as reservoirs of cat and dog allergens. Thus, children with asthma and other allergic diseases will be exposed to cat and dog allergens at school and by contact with pet owners, even if they avoid animal allergens at home.
Einarsson R., Munir A.K.M., Dreborg S.K.G. (1995):
Allergens in school dust: II. Major mite (Der p I, Der f I) allergens in dust from Swedish schools. J Allergy Clin Immunol. 95 (1): 1049-1053
Einarsson et al., studied the levels of the major mite allergens Der p I and Der f I in dust 4 schools school in central Sweden in relation to some building characteristics t aking into account cleaning frequency and cleaning procedures used for cleaning tables, chairs, and floors. In all schools the concentration of mite allergens in dust samples from table surfaces was significantly higher than in dust samples from chairs and floors. Students may transport mite allergens to the classrooms in their hair, and when they sit at the table mites or mite allergens fall down on the table. The concentration of mite allergen was significantly lower in dust from all surfaces in the school were routine cleaning procedure comprised of both dry and wet sweeping was existing. Significantly lower concentrations of mite allergen were found on chair surfaces cleaned by dry cleaning than on chair surfaces cleaned by wet methods. Significantly lower concentrations of mite allergens were found in floor dust in classrooms cleaned by only wet cleaning. In general it was stated that mite allergen levels in dust from Swedish schools are similar to the levels found in homes of babies with a high risk for allergy development and homes of mite-sensitised children from the same region; mite allergen exposure in schools is an occupational hazard.
Lundin L. (1999):
Allergic and non-allergic students' perception of the same high school environment. Indoor Air Jun; 9 (2): 92-102
Lundin et al., performed a study with the aim to describe how allergics and non- allergics perceive the same environment at high school students in a town in southern Sweden. Only 45% of the students were non-allergic but since the symptom frequency among non-allergic students was normal, the schools were classified as healthy. However, compared to the non-allergic students, a higher percentage among the allergics suffered from symptoms every week, a lower percentage was satisfied with the air quality and the cleaning, and a higher percentage was bothered every week by temperature, stuffy/stale air, bad odour, passive smoke, bad lighting, noise, dust and dirt. The findings could indicate that allergics note discomfort earlier than non-allergics by being more critical in general and especially critical to factors that could effect their health. The findings could also indicate that awareness of ones own sensitivity could lead to attention to different risk factors, which in turn could lead to stress/anxiety, which could make symptoms worse. The conclusion is that it is important to take allergy into consideration when the environment is assessed.
Munir A.K., Einarsson R., Schou C., Dreborg S.K. (1993):
Allergens in school dust. I. The amount of the major cat (Fel d I) and dog (Can f I) allergens in dust from Swedish schools is high enough to probably cause perennial symptoms in most children with asthma who are sensitised to cat and dog. Journal of Allergy & Clinical Immunology. 91 (5): 1067-74.
Munir et al., performed a study to the levels of Fel d I and Can f I in dust from tables, chairs, and floors in 29 classrooms in four Swedish schools. Higher amounts of Fel d I were found on chairs (geometric mean, 953 ng per gram of dust) than on tables (525 ng/gm) and floors (134 ng/gm). The concentration of Can f I (5.3 ng/gm) on chairs was 2 to 20 times higher than Fel d I. The concentration of Can f I (200 ng/gm) in dust from floors was twice as high as that of Fel d I. The authors hypothesised that allergen is brought to schools on the clothes of students and teachers and concluded that the levels of the two major allergens from furred pets (i.e., Fel d I and Can f I) in Swedish schools are probably high enough to sensitise children and to induce asthma in most children who are allergic to cats or dogs.
Norbäck D (1995):
Subjective Indoor Air Quality in Schools-the Influence of High Room Temperature, Carpeting, Fleecy Wall Materials and Volatile Organic Compounds (VOC), Indoor Air, Vol. 5, pp 237-246
Norbäck et al., studied relations between subjective indoor air quality (SIAQ) and measured IAQ among school personnel (N=97) in six mid-Swedish primary schools. The author found that perception of high room temperatures was related to a poor climate of co-operation, fleecy wall materials, and the concentration of volatile organic compounds (VOC), including xylene, limonene, and butanols. Perception of air dryness was related to atopy, work stress, poor climate of co- operation, high room temperature, low air humidity, and high VOC concentration, including, limonene, and n-alkanes. Perception of dusty air was related to work stress, the role of schoolteacher, and exposure to 2-ethyl-1- hexanol. No relations were found between SIAQ and CO2, building age, or respirable dust.
Norbäck D., Torgen M., Edling C. (1990):
Volatile organic compounds, respirable dust, and personal factors related to prevalence and incidence of sick building syndrome in primary schools. British Journal of Industrial Medicine, 47 (11): 733-41
Norbäck et al., also studied indoor exposures among personnel in six primary schools during a four-year longitudinal study including the incidence and prevalence of sick building syndrome (SBS). The mean concentration of carbon dioxide was above the recommended value of 800 ppm in all schools, indicating a poor outdoor air supply. Respirable dust was enhanced at lower ventilation rates and high air humidity. Indoor concentration of volatile organic compounds (VOC) was enhanced at high room temperatures. Chronic SBS was related to VOC, previous wall to wall carpeting in the schools, hyper-reactivity, and psychosocial factors. Incidence of new SBS was related to concentration of respirable dust, current smoking, and the psychosocial climate. Remission of hyperreactivity, decrease in sick leave owing to airway illness, removal of carpeting in the schools, and moving from new to old dwellings resulted in a decrease in SBS score. Because poor air quality in schools could also affect the children, it may have implications for the state of health of a large proportion of the population.
Norbäck D., Walinder R., Wieslander G., Smedje G., Erwall C., Venge P.(2000):
Indoor air pollutants in schools: nasal patency and biomarkers in nasal lavage. Allergy. 55 (2): 163-70
Norbäck et al., performed another study in 12 randomly selected primary schools in an urban community in central Sweden. Nasal lavage (NAL) was investigated analysing eosinophil cationic protein (ECP), myeloperoxidase (MPO), lysozyme, and albumin in NAL fluid. Hygienic measurements of airborne pollutants were performed in classrooms, outside the pollen season it was found that most classrooms (83%) did not meet the Swedish ventilation standards. The most consistent findings were observed for formaldehyde, NO2, and Aspergillus spp., related to both decreased nasal patency and increase of eosinophil cationic protein (ECP) and lysozyme in NAL. The presence of yeast was associated with an increase of ECP and lysozyme in NAL, but was not related to nasal patency. It was concluded that air pollutants in the classroom air may influence nasal patency and inflammatory response in the nasal mucosa.
Smedje G., Norbäck D.(2000):
New ventilation systems at select schools in Sweden-effects on asthma and exposure, 2000, Arch Environ Health, 55 (1): 18-25
Smedje et al., studied the possible impact of improving school ventilation on health and exposure of pupils in 39 randomly selected schools. In 12% of the classrooms, new ventilation systems were installed between 1993 and 1995; the subsequent air- exchange rate increased and the relative humidity and concentration of several airborne pollutants were reduced compared with classrooms in non improved buildings. The reporting of at least one asthmatic symptom and the reporting of more asthmatic symptoms in 1995 than in 1993 were less common among the 143 pupils who attended schools with new ventilation systems.
Smedje G., Norbäck D., Edling C (1997):
Asthma among secondary schoolchildren in relation to the school environment. Clinical & Experimental Allergy. 27 (11): 1270-8
Smedje et al., studied in another study the prevalence of current asthma among secondary pupils and its relationship to environment of 11 schools, to personal factors and domestic exposures. Current asthma was more common in those who had an atopic disposition, or food allergy, or who had attended a day care centre for several years. Using multiple logistic regression they found that current asthma was related to several factors in the school environment: there were more pupils with current asthma in schools that were larger, had more open shelves, lower room temperature, higher relative air humidity, higher concentrations of formaldehyde or other volatile organic compounds, viable moulds or bacteria or more cat allergen in the settled dust. Although the pupils attended school for a minor part of their time, this study indicates that the quality of the school environment is of importance and may affect asthmatic symptoms. Although the pupils attended school for a minor part of their time, our study indicates that the quality of the school environment is of importance and may affect asthmatic symptoms. The classrooms should be: furnished so dust-binding fittings are minimised, with air exchange rate according to standards, regularly maintained and cleaned so moisture damage avoided and allergen burden minimised.
Walinder R., Norbäck D., Wieslander G., Smedje G., Erwall C., Venge P (1999):
Nasal patency and lavage biomarkers in relation to settled dust and cleaning routines in schools. Scandinavian Journal of Work, Environment & Health. 25 (2): 137-43
Walinder et al., performed a study in 12 randomly selected primary schools to determine the relations between settled dust and cleaning routines in classrooms on one hand, and nasal symptoms, nasal cavity dimensions, and the concentration of selected biomarkers of inflammation in nasal lavage on the other. The amount of settled dust was positively related to subjective nasal obstruction and reduced nasal patency measured with acoustic rhinometry. The levels of ECP in the lavage were correlated with a lower cleaning frequency. It was concluded that the results indicate that the actual dust levels in Swedish classrooms can affect the occurrence of nasal obstruction among school personnel. These findings illustrate the need for adequate cleaning procedures to minimise the environmental effects on the airway mucosal.
Walinder R., Norbäck D., Wieslander G., Smedje G., Erwall C., Venge P (1998):
Nasal patency and biomarkers in nasal lavage--the significance of air exchange rate and type of ventilation in schools. International Archives of Occupational & Environmental Health. 71 (7): 479-86
Walinder et al., examined in another study the relationships between the ventilation rate and the type of ventilation system, on the one hand, and objective nasal measures, on the other using similar methods as described before. The results indicate that both a low air exchange rate and mechanical ventilation systems based on dilution can be associated with reduced nasal patency and an inflammatory biomarker response of the nasal mucosal among school personnel. The only school with sufficient ventilation according to the current Swedish recommendations had a displacement system and the fewest signs of nasal reactions among the personnel.
Wickman M., Egmar A., Emenius G., Almqvist C., Berglind N., Larsson P., Van Hage-Hamsten M. (1999):
Fel d 1 and Can f 1 in settled dust and airborne Fel d 1 in allergen avoidance day-care centres for atopic children in relation to number of pet-owners, ventilation and general cleaning, 1999, Clinical & Experimental Allergy. 29 (5): 626-32.
Wickman et al., studied the concentrations of cat (Fel d 1) and dog (Can f 1) allergens in settled dust and airborne cat allergen in day-care centres in relation to pet ownership among children and staff, ventilation and general cleaning in 12 allergen avoidance day-care centres and 22 conventional day-care centres. Airborne cat allergen levels and air change rate per hour were measured in eight allergen avoidance and seven conventional centres. A questionnaire that focused on keeping of cat and dog among staff and children and frequency of general cleaning was used. In the allergen avoidance day-care centres neither children nor staff reported ownership of cats or dogs, compared with 21/22 of the conventional centres in which children and staff kept furred animals. Fel d 1 and Can f 1 were found in settled dust in all day-care centres.
In the allergen avoidance compared with the conventional centres the concentrations of Fel d 1 and Can f 1 were lower, Fel d 1: median 0. 64 µg/g vs 5.45 µg/g and Can f 1: 0.39 µg/g vs 2.51, both P < 0.001, and airborne Fel d 1 was also lower in the allergen avoidance centres compared with the control centres, 1.51 ng/m3 vs 15.8 ng/m3, P = 0.002. A correlation was found between airborne and settled Fel d 1, rs = 0.75, P < 0.001. Furthermore, a correlation was found between increased ACH and decreased levels of Fel d 1 in the air in the day-care centres with no cat-owners, rs = - 0.86, P = 0.007. No relation was found between levels of cat or dog allergen and amount of general cleaning. Not keeping pets seems to reduce children's exposure to pet-allergen in their 'working environment'. Additionally, appropriate ventilation seems to reduce Fel d 1 in the air in day-care centres.