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Clin Exp Allergy. 1998 Nov;28(11):1389-96.

Mechanical ventilation protects one-storey single-dwelling houses against increased air humidity, domestic mite allergens and indoor pollutants in a cold climatic region.

Author information

1
Department of Environmental Health, Stockholm County Council, Stockholm, Sweden; Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.

Abstract

BACKGROUND:

Poor ventilation in modern, highly insulated housing is an important factor in promoting indoor humidity levels to exceed 7 g/kg in cold climatic regions.

OBJECTIVE:

To investigate the ventilation rate in houses with different ventilation systems in relation to indoor air humidity, domestic mite allergen levels and volatile organic compounds (VOC).

METHODS:

Measurements were performed regarding ventilation rate, indoor temperature, air humidity, mattress mite allergen concentrations using enzyme-linked immunosorbent assay and total indoor VOC in 59 similarly constructed one-storey single-dwelling houses. In 22 of the houses, a mechanical supply and exhaust ventilation were installed after construction.

RESULTS:

In only five of the houses with mechanical supply and exhaust ventilation the air exchange rate per hour (ACH) was below 0. 5 compared with 24 of the 29 houses with natural ventilation (OR = 0. 06, CI 95% 0.01-0.2). None of the 23 houses with an ACH >/= 0.5 had an absolute indoor humidity (AIH) of 7 g/kg air or more, compared with 10 of the 36 houses with an ACH < 0.5 (P = 0.01 ). In none of the 23 houses with an ACH >/= 0.5 were concentrations of mite allergen exceeding 2 microg/g of dust found, compared with six of the 36 houses (17%) with an ACH below 0.5 (P = 0.04). Further, 10 of the 34 houses with a total VOC exceeding 200 microg/m3 had mite allergen in mattress dust exceeding 0.5 microg/g, compared with one of the 22 houses with VOC < 200 microg/m3 (P = 0.04).

CONCLUSION:

The study shows that in modern, highly insulated, one-storey single-dwelling houses in cold temperate regions, mechanical ventilation increases the possibility of reaching an ACH of >/= 5 which protects against indoor humidity levels contributing to mite survival as well as high levels of indoor air pollutants in winter.

PMID:
9824412
[Indexed for MEDLINE]

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