Newswise — As temperatures rise and allergy season heat up, it isn't just the mold and pollen counts that are making St. Louisans sneeze. Dust allergies can trigger itchy red eye and runny noses.
Kee-Hean Ong, Ph.D., an assistant professor of Environmental and Occupational Health at Saint Louis University, studies methods for reducing indoor microbes from carpets. Indoor microbes can include dust mites, dust mite allergens and mold.
Ong's tip to keep dust mites at bay? It's as simple as regularly vacuuming with a vacuum with a good HEPA filter.
"Just vacuum," he said. "Replace the bags in your vacuum cleaner often so they don't get too full."
Ong was the lead author on "Inactivation of Dust Mites, Dust Mite Allergen, and Mold from Carpet," which was published in the August 2014 edition of the Journal of Occupational and Environmental Hygiene.
The paper looked at the accumulation of contaminants in carpet that may trigger allergies or asthma symptoms in both children and adults. In the study, carpets were artificially worn to simulate 1 to 2 years of wear in a four-person household. The worn carpets were inoculated together with a common indoor mold and house dust mites and incubated for six weeks to allow time for dust mite growth on the carpet. The carpets were then randomly assigned to one of the four treatment groups.
Four moderately low-hazard, nondestructive methods were selected as treatments: vacuuming, steam-vapor, Neem oil (a natural tree extract), and benzalkonium chloride (a quaternary ammonium compound). Ong said steam vapor proved to be the best method to kill the dust mites, however, he also noted that the steam vapor method and vacuuming perform equally well in inactivating or removing dust mite allergens (p = 0.084). Both these physical methods have higher efficacy when compared to the chemical method on dust mite allergens (p = 0.002).
The two physical methods, steam vapor and vacuuming, have no statistically significant efficacy in inactivating dust mite allergens (p = 0.084), but have higher efficacy when compared to the chemical method on dust mite allergens (p = 0.002). There is no statistically significant difference in the efficacy for reducing mold in carpet (p > 0.05) for both physical and chemical methods. The steam-vapor treatment effectively killed dust mites and denatured dust mite allergen in the laboratory environment.
Ong noted that while the steam vapor method shown to be the best method for killing dust mites and allergens in the laboratory, killing or inactivating is not the same as removing the pollutant. Therefore, applying steam to the carpet to inactivate the dust mites and its allergen, and vacuuming it away is Ong's advice. Furthermore, the practicality and feasibility of using the steam vapor method on a large area still needs to be evaluated.
"So chemicals are not needed to keep the mites, mold, and allergens down in your carpet but before you invest in a steam vapor method more studies need to be done in homes and additional ways of applying steam in a cost-efficient manner must be developed," said Roger Lewis, Ph.D. co-author and director of the Environmental Health Research Laboratory at Saint Louis University. "Meantime, it may be wise to invest in a dry-vacuuming approach that has a high suction and air flow that keeps the allergens from getting through the vacuum cleaner and into the air. The good news is that more and more vacuum cleaners today are now made to reduce allergens from being released after vacuuming."
The American College of Allergy, Asthma and Immunology recommends those with a known dust allergy limit the places dust mites can hide by opting for wood flooring over wall-to-wall carpeting. Using dust-mite proof pillow cases that are washed regularly in hot water also is a good idea.
Other authors on the paper include Zhengmin Quin, M.D. Ph.D., chair of the department of Epidemiology at Saint Louis University, and Anupriya Dixit, Mingan Yang and Maureen MacDonald.
On April 24, 2015, it was announced that the paper was selected as the winner of the American Industrial Hygiene Association's Indoor Environmental Quality Committee's Lila Albin Award for the best IEQ paper of 2014. Ong and Lewis accepted the award award during the American Industrial Hygiene Conference and Exposition in Salt Lake City on June 2.
Also at the conference, Lewis received the Fellow Award from the American Industrial Hygiene Association.
The Saint Louis University College for Public Health and Social Justice is the only academic unit of its kind among the nearly 250 Catholic institutions of higher education in the United States.
With a focus on finding innovative and collaborative solutions for complex global health problems, the College offers nationally recognized programs in global public health, social work, health management and health policy, epidemiology, biostatistics, environmental and occupational health, behavioral science and health education, emergency management, biosecurity and disaster preparedness, and criminology and criminal justice.
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