Objectives: As a part of the worldwide European Community respiratory health survey, possible relations between symptoms of asthma, building characteristics, and indoor concentration of volatile organic compounds (VOCs) in dwellings were studied.
Methods: The study comprised 88 subjects, aged 20-45 years, from the general population in Uppsala, a mid-Swedish urban community, selected by stratified random sampling. Room temperature, air humidity, respirable dust, carbon dioxide (CO2), VOCs, formaldehyde, and house dust mites were measured in the homes of the subjects. They underwent a structured interview, spirometry, peak expiratory flow (PEF) measurements at home, methacholine provocation test for bronchial hyperresponsiveness, and skin prick tests. In addition, serum concentration of eosinophilic cationic protein (S-ECP), blood eosinophil count, and total immunoglobulin E (S-IgE) were measured.
Results: Symptoms related to asthma were more common in dwellings with house dust mites, and visible signs of dampness or microbial growth in the building. Significant relations were also found between nocturnal breathlessness and presence of wall to wall carpets, and indoor concentration of CO2, formaldehyde, and VOCs. The formaldehyde concentration exceeded the Swedish limit value for dwellings (100 micrograms/m3) in one building, and CO2 exceeded the recommended limit value of 1000 ppm in 26% of the dwellings, showing insufficient outdoor air supply. Bronchial hyperresponsiveness was related to indoor concentration of limonene, the most prevalent terpene. Variability in PEF was related to two other terpenes; alpha-pinen and delta-karen.
Conclusion: Our results suggest that indoor VOCs and formaldehyde may cause asthma-like symptoms. There is a need to increase the outdoor air supply in many dwelling, and wall to wall carpeting and dampness in the building should be avoided. Improved indoor environment can also be achieved by selecting building materials, building construction, and indoor activities on the principle that the emission of volatile organic compounds should be as low as reasonably achievable, to minimise symptoms related to asthma due to indoor air pollution.