BACKGROUND: Allergen avoidance is of considerable interest in the treatment and even prevention of asthma. Attempts to control house dust mites have included environmental manipulation in homes in an attempt to reduce humidity below a level that favors mite survival. This appears to have some benefit in Scandinavia, but a previous attempt with mechanical ventilation heat pump recovery (MVHR) units in the UK failed to achieve the desired results. OBJECTIVE: We report a study using an additional central dehumidification modification of the MVHR (MVHRcd) in an attempt to reduce allergen levels in houses of asthmatic subjects. METHODS: Ten houses of asthmatic patients allergic to dust mites and 10 architectural control houses were studied. The active houses were fitted with an MVHRcd unit in November/December 1994 and activated in January 1995. The active and control houses were monitored continuously for internal temperature and humidity by using digital sensors in the asthmatic and control bedrooms. Dust samples were collected to determine allergen levels at baseline (January 1994) and 3, 6, 9, and 15 months after switching on the units. RESULTS: The winter seasonal average humidity fell from 50% relative humidity (RH) in control bedrooms to 37% RH in asthmatic bedrooms compared with 72% RH in the ambient air as measured on the intake of the MVHRcd systems. There was no corresponding change in seasonal mean temperature within the houses. Although the temperature and humidity weekly and seasonal means remained below the study target of 45% RH or 7 g/kg absolute humidity at 21 degrees C, there were transient rises in humidity detected by the sensors in the houses with MVHRcd systems. Allergen levels fell both in active and control houses during the study period, but there was no significant advantage gained from the installation of MVHRcd systems. CONCLUSION: The MVHRcd system failed to confer a benefit in terms of mite allergen reduction despite apparently adequate control of temperature and humidity.
BACKGROUND: Allergen avoidance is of considerable interest in the treatment and even prevention of asthma. Attempts to control house dust mites have included environmental manipulation in homes in an attempt to reduce humidity below a level that favors mite survival. This appears to have some benefit in Scandinavia, but a previous attempt with mechanical ventilation heat pump recovery (MVHR) units in the UK failed to achieve the desired results. OBJECTIVE: We report a study using an additional central dehumidification modification of the MVHR (MVHRcd) in an attempt to reduce allergen levels in houses of asthmatic subjects. METHODS: Ten houses of asthmatic patientsallergic to dust mites and 10 architectural control houses were studied. The active houses were fitted with an MVHRcd unit in November/December 1994 and activated in January 1995. The active and control houses were monitored continuously for internal temperature and humidity by using digital sensors in the asthmatic and control bedrooms. Dust samples were collected to determine allergen levels at baseline (January 1994) and 3, 6, 9, and 15 months after switching on the units. RESULTS: The winter seasonal average humidity fell from 50% relative humidity (RH) in control bedrooms to 37% RH in asthmatic bedrooms compared with 72% RH in the ambient air as measured on the intake of the MVHRcd systems. There was no corresponding change in seasonal mean temperature within the houses. Although the temperature and humidity weekly and seasonal means remained below the study target of 45% RH or 7 g/kg absolute humidity at 21 degrees C, there were transient rises in humidity detected by the sensors in the houses with MVHRcd systems. Allergen levels fell both in active and control houses during the study period, but there was no significant advantage gained from the installation of MVHRcd systems. CONCLUSION: The MVHRcd system failed to confer a benefit in terms of mite allergen reduction despite apparently adequate control of temperature and humidity.
Authors: Jay Portnoy; Jeffrey D Miller; P Brock Williams; Ginger L Chew; J David Miller; Fares Zaitoun; Wanda Phipatanakul; Kevin Kennedy; Charles Barnes; Carl Grimes; Désirée Larenas-Linnemann; James Sublett; David Bernstein; Joann Blessing-Moore; David Khan; David Lang; Richard Nicklas; John Oppenheimer; Christopher Randolph; Diane Schuller; Sheldon Spector; Stephen A Tilles; Dana Wallace Journal: Ann Allergy Asthma Immunol Date: 2013-12 Impact factor: 6.347
Authors: James Krieger; David E Jacobs; Peter J Ashley; Andrea Baeder; Ginger L Chew; Dorr Dearborn; H Patricia Hynes; J David Miller; Rebecca Morley; Felicia Rabito; Darryl C Zeldin Journal: J Public Health Manag Pract Date: 2010 Sep-Oct
Authors: Mario Sánchez-Borges; Enrique Fernandez-Caldas; Wayne R Thomas; Martin D Chapman; Bee Wah Lee; Luis Caraballo; Nathalie Acevedo; Fook Tim Chew; Ignacio J Ansotegui; Leili Behrooz; Wanda Phipatanakul; Roy Gerth van Wijk; Demoly Pascal; Nelson Rosario; Motohiro Ebisawa; Mario Geller; Santiago Quirce; Susanne Vrtala; Rudolf Valenta; Markus Ollert; Giorgio Walter Canonica; Moises A Calderón; Charles S Barnes; Adnan Custovic; Suwat Benjaponpitak; Arnaldo Capriles-Hulett Journal: World Allergy Organ J Date: 2017-04-18 Impact factor: 4.084