Crowding: risk factor or protective factor for lower respiratory disease in young children?

Abstract Background To study the effects of household crowding upon the respiratory health of young children living in the city of São Paulo, Brazil. Methods Case-control study with children aged from 2 to 59 months living within the boundaries of the city of São Paulo. Cases were children recruited from 5 public hospitals in central São Paulo with an acute episode of lower respiratory disease. Children were classified into the following diagnostic categories: acute bronchitis, acute bronchiolitis, pneumonia, asthma, post-bronchiolitis wheezing and wheezing of uncertain aetiology. One control, crudely matched to each case with regard to age (<2, 2 years old or more), was selected among healthy children living in the neighborhood of the case. All buildings were surveyed for the presence of environmental contaminants, type of construction and building material. Plans of all homes, including measurements of floor area, height of walls, windows and solar orientation, was performed. Data were analysed using conditional logistic regression. Results A total of 313 pairs of children were studied. Over 70% of the cases had a primary or an associated diagnosis of a wheezing illness. Compared with controls, cases tended to live in smaller houses with less adequate sewage disposal. Cases and controls were similar with respect to the number of people and the number of children under five living in the household, as well the number of people sharing the child's bedroom. After controlling for potential confounders, no evidence of an association between number of persons sharing the child's bedroom and lower respiratory disease was identified when all cases were compared with their controls. However, when two categories of cases were distinguished (infections, asthma) and each category compared separately with their controls, crowding appeared to be associated with a 60% reduction in the incidence of asthma but with 2 1/2-fold increase in the incidence of lower respiratory tract infections (p = 0.001). Conclusion Our findings suggest that household crowding places young children at risk of acute lower respiratory infection but may protect against asthma. This result is consistent with the hygiene hypothesis.

Methodology of CO2 emission evaluation in the life cycle of office building facades

The construction industry is one of the greatest sources of pollution because of the high level of energy consumption during its life cycle. In addition to using energy while constructing a building, several systems also use power while the building is operating, especially the air-conditioning system. Energy consumption for this system is related, among other issues, to external air temperature and the required internal temperature of the building. The facades are elements which present the highest level of ambient heat transfer from the outside to the inside of tall buildings. Thus, the type of facade has an influence on energy consumption during the building life cycle and, consequently, contributes to buildings' CO2 emissions, because these emissions are directly connected to energy consumption. Therefore, the aim is to help develop a methodology for evaluating CO2 emissions generated during the life cycle of office building facades. The results, based on the parameters used in this study, show that facades using structural glazing and uncolored glass emit the most CO2 throughout their life cycle, followed by brick facades covered with compound aluminum panels or ACM (Aluminum Composite Material), facades using structural glazing and reflective glass and brick facades with plaster coating. On the other hand, the typology of facade that emits less CO2 is brickwork and mortar because its thermal barrier is better than structural glazing facade and materials used to produce this facade are better than brickwork and ACM. Finally, an uncertainty analysis was conducted to verify the accuracy of the results attained. (C) 2011 Elsevier Inc. All rights reserved.