Navigation Links
Elusive ultrafine indoor air contaminants yield to NIST analysis
Date:12/7/2011

Researchers at the National Institute of Standards and Technology (NIST) spent 75 days on the job carrying out some very important homeworkmeasurements in a "typical dwelling" of the release, distribution and fate of particles almost as tiny as the diameter of a single DNA molecule. Particles ranging in size from 100 nanometers down to 2.5 nanometers that were emitted by gas and electric stoves, hair dryers, power tools and candles were tracked and analyzed.*

Monitoring such tiny particles was made possible by NIST advances in measurement capabilities. Measurements were carried out in weeks of experiments at a 340-square-meter (1,500-square-feet) test house on the NIST campus in Gaithersburg, Md. The researchers used the data to develop a model for predicting changes in the size and distribution of so-called ultrafine particles (technically, particles smaller than 100 nanometers) discharged by tools, appliances and other sources.

The measurements and model will further efforts to explain the dynamics of ultrafine particles, an area of growing interest among environmental and health researchers. They also will advance work to develop accurate and reliable methods for determining how changes in heating and cooling systems, often done to reduce energy consumption, will affect indoor environments.

"If we can understand and predict the dynamics of these extremely small indoor air contaminants, designers and equipment manufacturers can avoid potential negative impacts on the environment inside homes and buildings and may even devise ways to improve conditions and save energy at the same time," explains NIST engineer Andrew Persily.

Utrafine particles are produced naturallyby forest fires and volcanoes, for exampleas well as by internal combustion engines, power plants and many other human-made sources. Although ever present in outdoor and indoor environments, ultrafine particles have eluded detection, and are not subject to federal or state air quality standards. However, particles with nanoscale dimensions have been associated with a variety of human health problemsespecially heart, lung and blood disorders.

Because we spend most of our time indoors, however, the bulk of human exposure to ultrafine particles occurs in homes and buildings. Typically, releases of the tiny particles occur in periodic burstsduring cooking or hair drying, perhapsbut airborne concentrations during these episodes can greatly exceed outdoor levels, according to the NIST team.

The researchers measured the airborne concentrations of ultrafine particles at regular intervals after they were emitted by gas and electric stoves, candles, hair dryers and power tools. With their recently enhanced capabilities, the team could measure particles about four times smaller than in previous studies of indoor air contaminants.

Tests were conducted with the house central fan either on or off, which made a major difference in the behavior of ultrafine particles. With the fan off, these very small particles collide with each other and coagulateor combineduring the first 2.5 minutes following a blast of ultrafine particles from an appliance or tool. In the process, they form successively larger particles, decreasing airborne concentrations of particles. As particles grow larger, they tend to settle on surfaces more quickly.

With the central fan recirculating air, ultrafine particles tend, in roughly equal proportions, to coagulate or settle on surfaces. Under both fan conditions, ventilation accounted for the removal of no more than about 5 percent of ultrafine particles.

Tests also revealed that for many indoor sources, such as stovetop cooking with gas, more than 90 percent of the particles emitted were smaller than 10 nanometers. In turn, emissions of smaller particles result in higher airborne concentrations that dissipate primarily through coagulation.


'/>"/>
Contact: Mark Bello
mark.bello@nist.gov
301-975-3776
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology news :

1. Scripps research team achieves critical step to opening elusive class of compounds to drug discovery
2. Discovery illuminates elusive proton channel gene in dinoflagellates
3. Novel approach scores first success against elusive cancer gene
4. Researchers use neutrons to spy on the elusive hydronium ion
5. Elusive prey
6. Anglo-French team discover elusive gene that makes platelets gray
7. Genetic study clarifies evolutionary origin of elusive montane red fox
8. Nature study: Jefferson researchers unravel proteins elusive role in embryo and disease development
9. CSHL scientists identify elusive neuronal targets of deep brain stimulation
10. The elusive intermediary
11. New discovery could aid development of elusive bovine mastitis vaccine
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/14/2017)... IBM ) is introducing several innovative partner startups at VivaTech ... startups and global businesses, taking place in Paris ... will showcase the solutions they have built with IBM Watson ... France is one of the most dynamic ... in the number of startups created between 2012 and 2015*, ...
(Date:5/6/2017)... SINGAPORE , May 5, 2017 ... has just announced a new breakthrough in biometric ... that exploits quantum mechanical properties to perform ... new smart semiconductor material created by Ram Group ... across finance, entertainment, transportation, supply chains and security. ...
(Date:4/17/2017)... , April 17, 2017 NXT-ID, Inc. ... company, announces the filing of its 2016 Annual Report on Form ... Exchange Commission. ... Form 10-K is available in the Investor Relations section of the ... on the SEC,s website at http://www.sec.gov . 2016 ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... ... of a United States multicenter, prospective clinical study that demonstrates the accuracy ... test capable of identifying clinically significant acute bacterial and viral respiratory tract ...
(Date:10/11/2017)... ... October 11, 2017 , ... The ... context, enabling overexpression experiments and avoiding the use of exogenous expression plasmids. The ... transformative for performing systematic gain-of-function studies. , This complement to loss-of-function studies, ...
(Date:10/11/2017)... LAGUNA HILLS, Calif. , Oct. 11, 2017 ... London (ICR) and University of ... prognostic tool to risk-stratify patients with multiple myeloma (MM), in ... nine . The University of Leeds ... by Myeloma UK, and ICR will perform the testing services ...
(Date:10/10/2017)... ... October 10, 2017 , ... ... pharmaceutical company advancing targeted antibody-drug conjugate (ADC) therapeutics, today confirmed licensing rights ... (Hybrid Polymerized Liposomal Nanoparticle), a technology developed in collaboration with Children’s Hospital ...
Breaking Biology Technology: