asthma

Scientific evidence exists of an association between dampness and mould in buildings and of an increased risk of health effects for occupants, usually associated with the respiratory system. It is difficult to establish the exact prevalence of residential dampness, but according to WHO, it is likely to be in the order of 10-50%.  

In past 20 years, the average prevalence of asthma in China has been growing up from 0.9 % to about3.0 %. We carried out these studies to find out the reasons and relative molecular mechanisms. Datamultiple-regression was used for prevalence and risk factor investigation (1990-2000) and animalexperiments were used for mechanism study.

The incidence of asthma and allergy has increased throughout the developed world over the past 30-50years, roughly the same time period that exposure to phthalates has increased. An ongoing study inSweden, Damp Buildings and Health, showed associations between asthma anddi(2-ethyl-hexyl)-phthalate concentration in dust and between eczema and rhinitis andbutylbenzyl-phthalate.

Many homes in New Zealand are poorly constructed and maintained for the climate with inadequateheating resulting in winter temperatures that frequently fall below the World Health Organisationrecommended level of 18C. Approximately 30% of New Zealand homes are heated by unfluedportable gas heaters. To investigate the link between the indoor air environment and respiratory healtheffects in children, we studied 409 households that used unflued gas heaters or electric heating andhad an asthmatic child.

An epidemiological study was instigated by reports from a Denver office building of cases of building-related asthma and hyper-sensitivity pneumonitis. The methodology used was a cross-sectional and self-administered questionnaire completed by workers in this building and a similar one in the suburbs. The Denver workers showed a much higher rate of respiratory disease than the suburban workers (512 compared to 281).

Explores possible relations between symptoms of asthma, building characteristics and indoor concentration of volatile organic compounds in residential buildings. 88 persons from middle Sweden were studied. Measurements were taken at home of room temperature, air humidity, respirable duct, carbon dioxide, VOCs, formaldehyde and house dust mites. Health tests were also performed. Found that symptoms related to asthma were more common in homes with house dust mites and visible signs of dampness or microbial growth.

States that schools often have a low air change rate. The study attempted to find out if an improvement in school ventilation would lead to improved health in pupils. A questionnaire was set for 1476 primary and secondary school pupils in 39 schools. 100 classrooms were monitored. New ventilation systems were installed in 12% of the classrooms over the survey period, increasing air change rate and reducing relative humidity and occurrence of a number of airborne pollutants. The study found that reporting of asthmatic symptoms decreased in the schools with new ventilation systems.

The literature for the control of dust mites by modification of the psychrometric conditions of the environment is reviewed from the standpoint of a building scientist or engineer, both to present to building science workers an envelope of microenvironment psychrometric conditions to use as control, and to highlight those areas of dust mite biology that require further research to complete the knowledge of the psychrometric envelope for dust mite viability.