[Associations between bioaerosols coming from livestock facilities and asthmatic symptoms in children]. / Zusammenhang zwischen Bioaerosolen aus Tierhaltungsanlagen und asthmatischen Symptomen bei Kindern.

Although health effects of occupational exposures to livestock emissions are known, potential associations between living in the neighbourhood of intensive livestock facilities and the risk of developing respiratory or allergic diseases are still under discussion. During routine school entry examinations in selected rural districts in Lower Saxony we asked parents about respiratory and allergic symptoms of their 5-6 year old children. A questionnaire with standardised questions of the ISAAC-Studies for respiratory and allergic symptoms and corresponding risk factors was used. Complementarily the children were examined for visible signs of flexural dermatitis and in a subsample the SX1-test was used as an in vitro test for inhalative IgE mediated sensibilisations in capillary blood. Individual exposure to bioaerosols (endotoxin, fungi, bacteria and total dust) coming from livestock facilities was estimated using a Lagrange dispersion model based on the emission rates and locations of the lifestock facilities. A total of 7943 questionnaires (response rate over 85%) were analysed, of which 3867 could be used for the correlation analyses between exposition to endotoxin and asthmatic symptoms. Multivariate logistic regression models were analyzed, considering an atopic disease of the parents as a potential effect modifier and not as a confounder. The prevalence of allergic and asthmatic symptoms is similar to the results of other comparable studies, e. g. "wheezing in the last 12 months" 15.9% for boys and 12.9% for girls. An increase in the prevalence of asthmatic symptoms for higher endotoxin levels was observed only for children of atopic parents. The multivariate controlled odds ratio for one unit logarithm endotoxin concentrations is 1.15, p-value 0.016. Similar effects were observed for other asthma indicators, but not for subjective criteria of the exposition, e. g. the distance to the next large livestock facility guesstimated by parents. Among the overall analysed potential associations between exposition to bioaerosols and asthmatic and allergic symptoms only a few were statistically significant. The discussed association between endotoxin and asthmatic symptoms in predisposed children needs further investigation.

["Breathing freely" in schools--results and model approaches concerning the air quality in classrooms]. / "Aufatmen in Schulen"--Untersuchungsergebnisse und Modellierungsansätze zur Raumluftqualität in Schulen.

Seven schools in Lower Saxony participated in a scientific re-search project measuring the concentration of carbon dioxide (CO2), indoor air temperatures and the relative air humidity in naturally ventilated classrooms on 58 days during the period of one year. The results are as follows: The hygienic reference value of 1500 ppm CO2 (in accordance with the official German regulation DIN 1946-2) was exceeded on 7 days in summer when measurements were taken (32% of all samples in summer) and on 32 days in winter (89% of all samples in winter). The mean CO2-concentration was 1316 ppm, 766 ppm and 1652 ppm in all samples (58 measuring days), summer samples (22 measuring days) and winter samples (36 measuring days), respectively. The mean indoor air temperature was 21.7 degrees C, 22.9 degrees C and 20.9 degrees C. The mean relative humidity was 50.7%, 54.3% and 48.5%. The mean number of persons per classroom (including the teacher) was 25.1, corresponding to a mean volume of 8.5 m3 for each person and a mean area of 2.9 m2 per person. A statistical association of CO2 concentration with season, outdoor temperature and the age of the windows was found. A software programme has been developed for calculating the concentration of CO2 depending on the number of persons and the ventilation rate in a classroom. A 3-level scheme based on CO2 concentration was developed to assess the air quality. The results showed that the classrooms were not ventilated regularly but depending on the outdoor temperature and the season. Deficits concerning all 3 parameters were found. It is very likely that the deficits are not limited to the schools participating in this project. Ventilation and indoor climate deficits might cause health problems and therefore lead to costly measurement programmes. To enable schools to take their own health-related measurements, measuring instruments were purchased which can be loaned to schools in Lower Saxony.