Featured Research

from universities, journals, and other organizations

Device Traps, Disables Harmful Bacteria

Date:
June 12, 2005
Source:
Washington University In St. Louis
Summary:
Engineers from Washington University in St. Louis and the University of Colorado at Boulder have removed bioaerosols -- airborne biological particulate matter -- from the air of a hospital therapy pool using a new generation of hybrid filters. The bioaerosols identified in the unnamed Midwestern hospital pool had sickened nine lifeguards who had become ill with hypersensitivity pneumonitis, a lung condition that mimics pneumonia symptoms.

Lars Angenent guides graduate student Rebecca Hoffman as she examines bacteria from air digesters under a high-powered epifluorescence microscope.
Credit: Photo by David Kilper

A team of engineers from Washington University in St. Louis and the University of Colorado at Boulder has removed bioaerosols — airborne biological particulate matter — from the air of a hospital therapy pool using a new generation of hybrid filters.

The bioaerosols identified in the unnamed Midwestern hospital pool had sickened nine lifeguards who had become ill with hypersensitivity pneumonitis, a lung condition that mimics pneumonia symptoms. This forced the pool to shut down. It is now reopened.

Lars T. Angenent, Ph.D., Washington University assistant professor of chemical engineering, and the Colorado engineers mounted three high-efficiency particulate air (HEPA) ultraviolet (UV) air filters on the ceiling of the pool room. They compared concentrations of total bacteria, culturable bacteria and airborne endotoxin — a poison present in gram-negative bacterial cell walls that can cause severe inflammatory responses — with and without the air filters operating under similar conditions. They compared the performance of the filters twice, one year apart, and found that the filters reduced concentrations of culturable bacteria by 69 and 80 percent during monitoring periods executed in respective years. The filters reduced concentrations of total bacteria by 12 and 76 percent, respectively, over the same span. But the filters did not affect airborne endotoxin concentrations.

"This specific filter has a blower that takes a high volume of air and puts it through a filter that screens bacteria and even smaller particles," said Angenent, a member of Washington University's Environmental Engineering Science Program. " And after the filter there is UV light; if something passes through the filter, the UV zaps it. It's a combination approach that appears very effective. The bacterium that had been causing illness was Mycobacterium avium, which can make immunocompromised people ill, and since a lot of elderly use therapy pools, that's a concern. However, since using the filters, no one has gotten sick."

The researchers also tested the hybrid filters in an environmentally controlled laboratory chamber to come up with the air-exchange rate for the therapy pool assays, among other parameters.

The researchers published their results in the Feb. 2005 issue of the Journal of Air & Waste Management Association. The study was supported by funds and equipment provided by Honeywell, Inc., UlraViolet Devices, Inc., and the National Science Foundation.

Angenent's collaborators are: Elmira Kujundicz, David A. Zander, and Mark Hernandez, of the University of Colorado Department of Civil, Environmental, and Architectural Engineering; and David E. Henderson and Shelly L. Miller, of the Department of Mechanical Engineering, University of Colorado.

Bioaerosols pose a threat to public health through infectious and toxic diseases. Today there are increased settings where people gather and can be affected by such bioaerosols. Among these "high-exposure environments" are correctional facilities, homeless shelters, healthcare facilities, and public transit systems. Additionally, the advent of hot tubs, hospital therapy pools and other warm-water leisure and therapy pools, many bioaerosols researchers believe, creates harbors that enhance the aerosolization of microorganisms, including strains of Legionella and Mycobacterium, that can cause diseases such as "lifeguard lung."

"The results of this study suggest that a reasonable reduction in bioaerosol concentrations can be achieved by installing this new generation of hybrid air filters," the authors conclude. "Engineering control methods must be balanced with constraints such as occupant comfort, economic factors, and building management strategies to ensure that the health risks associated with bioaerosol exposure are as low as practical."


Story Source:

The above story is based on materials provided by Washington University In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University In St. Louis. "Device Traps, Disables Harmful Bacteria." ScienceDaily. ScienceDaily, 12 June 2005. <www.sciencedaily.com/releases/2005/06/050609234020.htm>.
Washington University In St. Louis. (2005, June 12). Device Traps, Disables Harmful Bacteria. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2005/06/050609234020.htm
Washington University In St. Louis. "Device Traps, Disables Harmful Bacteria." ScienceDaily. www.sciencedaily.com/releases/2005/06/050609234020.htm (accessed September 30, 2014).

Share This



More Plants & Animals News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
Argentina Worries Over Decline of Soybean Prices

Argentina Worries Over Decline of Soybean Prices

AFP (Sep. 27, 2014) The drop in price of soy on the international market is a cause for concern in Argentina, as soybean exports are a major source of income for Latin America's third largest economy. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Mama Bear, Cubs Hang out in California Backyard

Mama Bear, Cubs Hang out in California Backyard

Reuters - US Online Video (Sep. 27, 2014) A mama bear and her two cubs climb trees, wrestle and take naps in the backyard of a Monrovia, California home. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins