Air contaminants vanishing into walls hamper lab experiments

Models of particle pollution have
been inconsistent, researchers say.

Models trying to predict airborne particle pollutants have been inconsistent over the past decade.

Some airborne particles can vanish into the walls of laboratory chambers, which could explain discrepancies in air pollution experiments. The findings of a new study suggest that models of particle pollution have been off for about a decade.

For their tests, researchers evaporated toluene, an ingredient of car exhaust that can form secondary organic aerosols, in a Teflon chamber.

Unlike previous researchers, they added “seed particles” such as ammonium sulfate. Adding these particles increases the aerosols that form when toluene vaporizes.

When there are no seed particles, the vapors end up sticking to or dissolving into the chamber walls, said Chris Cappa, an assistant professor at the University of California, Davis, and co-author of the study published in the Proceedings of the National Academies of Science.

“The walls of these chambers act as a sponge for the vapors,” Cappa said.

The findings of a new study suggest that models of particle pollution have been off for about a decade.

Cappa said that previous lab studies have underestimated secondary organic aerosol formation by about two to four times.

These aerosols, which are a byproduct of volatile organic compounds from vehicles and the burning of fossil fuels, are a major part of fine particle pollution.

Known as PM2.5, these particles can penetrate people’s lungs and disrupt their heart.

The discovery could explain why models that have tried to predict particulate levels from emissions inventories have not jibed with levels actually measured in the air.

“Accounting for such losses has the clear potential to bring model predictions and observations of organic aerosol levels into much closer agreement,” the authors wrote.

Laboratory models are often used to estimate regional air quality. And in the past 20 years, scientists have incorporated aerosols into climate models, too, because they can scatter or absorb radiation from the sun.

Aerosols that scatter sunlight would have a cooling effect, while those that absorb it have a warming effect.

The study was limited in that only one compound was tested. However, Cappa said the results should hold true for other aerosol precursors and the researchers plan on testing more.

The experiment doesn’t mean that regional air pollution is underestimated because scientists also use observations from the atmosphere.

“It’s not quite fair to say we’ve been underestimating impact of air pollution, but from a modeling standpoint we’ve been limited in our ability to properly set up strategies for improving air quality,” Cappa said.

Source: EHN

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Researchers develop new early warning system for toxins

Turkeys inspire smartphone-capable sensor for airborne chemicals

Turkey skin can shift color.
Photo courtesy of Tom Curtis/
FreeDigitalPhotos.net

Some may think of turkeys as good for just lunch meat and holiday meals. But bioengineers at the University of California, Berkeley, saw inspiration in the big birds for a new type of biosensor that changes color when exposed to chemical vapors.

This feature makes the sensors valuable detectors of toxins or airborne pathogens.

Turkey skin, it turns out, can shift from red to blue to white, thanks to bundles of collagen that are interspersed with a dense array of blood vessels. It is this color-shifting characteristic that gives turkeys the name "seven-faced birds" in Korean and Japanese.

The researchers say that spacing between the collagen fibers changes when the blood vessels swell or contract, depending upon whether the bird is excited or angry.

The amount of swelling changes the way light waves are scattered and, in turn, alters the colors we see on the bird's head.

Seung-Wuk Lee, UC Berkeley associate professor of bioengineering, led a research team in mimicking this color-changing ability to create biosensors that can detect volatile chemicals.

"In our lab, we study how light is generated and changes in nature, and then we use what we learn to engineer novel devices," said Lee, who is also a faculty scientist at the Lawrence Berkeley National Laboratory.

The researchers created a mobile app, called the iColour Analyser, to show that a smartphone photo of the sensor's color bands could be used to help identify toxins of interest. They described their experiments in a study to be published Tuesday, Jan. 21, in the journal Nature Communications.

Sensors that give off color readings are easier to use and read than conventional biosensors.

However, the major ones in development elsewhere can only detect a limited range of chemicals and, according to the researchers, they can be very difficult to manufacture.

"Our system is convenient, and it is cheap to make," said Lee. "We also showed that this technology can be adapted so that smartphones can help analyze the color fingerprint of the target chemical. In the future, we could potentially use this same technology to create a breath test to detect cancer and other diseases."
         
In copying this turkey-skin design, Lee and his team employed a technique they pioneered to mimic nanostructures like collagen fibers. The researchers found a way to get M13 bacteriophages, benign viruses with a shape that closely resembles collagen fibers, to self-assemble into patterns that could be easily fine-tuned.

The researchers found that, like collagen fibers, these phage-bundled nanostructures expanded and contracted, resulting in color changes. The exact mechanism behind the shrinking or expanding phage bundles is still unclear, but it's possible that the small amount of water in the phage is reacting to the chemical vapors, the researchers said.

The turkey-inspired biosensors were exposed to a range of volatile organic compounds, including hexane, isopropyl alcohol and methanol, as well as vapor of the explosive chemical TNT, at concentrations of 300 parts per billion. The researchers found that the viruses swelled rapidly, resulting in specific color patterns that served as "fingerprints" to distinguish the different chemicals tested.

The researchers showed that the biosensor's specificity to a target chemical could be increased by genetically engineering the DNA in the M13 bacteriophage to bind with sites specific to TNT.

The biosensor was then exposed to two additional chemicals, DNT and MNT, which have similar molecular structures to TNT. The engineered biosensor successfully distinguished TNT from the other chemicals with distinct color bands.

The biosensors were also able to signal changes in relative humidity, ranging from 20 percent to 90 percent, becoming redder with moister air and bluer with drier air.

The study lead author is Jin-Woo Oh, a former postdoctoral researcher in Lee's lab and now an assistant professor in the Department of Nanomaterial Engineering at Pusan National University in South Korea.

The National Science Foundation, the Defense Acquisition Program Administration and Agency for Defense Development in South Korea, Korea's Ministry of Education, Science and Technology, and Samsung helped support this work.

Source: University of California, Berkeley via EurekAlert! 

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Captain sues marine company for exposure to toxic fumes

Chemical exposure ruined health and future, seaman alleges

Health and safety lawsuits can be
expensive for employers.

Comal County resident Paul Whetstone seeks more than $1 million in damages from a marine company he claims exposed him to toxic chemicals.

He was ordered to repair his ship after the Ashton T ran aground on the Galveston north jetty in March 2012. Whetstone was first captain of the vessel.

Whetstone claims that he had to work “in a closed environment with little or no ventilation and ingested fumes and vapors from paint, polyurethane, welding gasses and other toxic and harmful substances in the air.”

Whetstone filed a Jones Act lawsuit against T&T Offshore Inc. and T&T Marine Inc. in Galveston County District Court.

In his suit, Whetstone claims he now wears a pacemaker following the incident last year in which “his heart and entire central nervous system shut down and he died.” Whetstone was revived and stabilized shortly afterwards, but rendered unable to work again, the suit says.

Seaman now requires pacemaker because of ship’s toxic fumes, court papers say

He also claims that he was made to eat and sleep “in this environment” and not allowed to leave the Ashton T.

Whetstone claims he requested adequate protection from “such harmful and deadly fumes, vapors and metals in the air” to no avail.

He was released from duty on April 28, 2012, and Whetstone states he was taken to San Antonio’s Baptist Hospital where surgeons installed the pacemaker.

According to the suit, the pacemaker “has permanently prevented the plaintiff from performing any form of work activity in the maritime and aviation fields because he is no longer qualified to maintain his ship captain and aviation license(s).”

A jury trial is requested.

Source: Southeast Texas Record

Combat chemical fumes with carbon air cleaners

Working with hazardous materials in closed environments or indoor spaces requires adequate health and safety measures.

Electrocorp air cleaners for chemicals and
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Shown: Welding fume extraction

Aside from personal protective equipment and improved ventilation, the right type of air cleaner can also significantly improve the air quality in these spaces.

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Occupational asthma: What you need to know

Exposure to certain chemicals and other substances
may cause or aggravate asthma, experts say.

Certain workplace chemicals or other pollutants may cause or aggravate asthma.

Asthma is a common lung disease brought on by inflammation and narrowing of the air passages that causes people to wheeze, cough and have trouble breathing.

The condition can affect a worker’s quality of life and ability to work and it can also be life threatening if it is not managed properly.

It is sometimes difficult for people with work-related asthma to make the connection because the symptoms are the same as regular asthma.

With work-related asthma, symptoms are usually worse on working days and workers may feel relief when they are away from the workplace during their days off and on vacation, for example.

Experts have identified a number of workplace pollutants that may cause or aggravate asthma:
  

• Chemicals, including isocyanates
• Metals and metal-working fluids
• Dyes, drugs and enzymes
• Grains, flours, plants, gums
• Animal and shellfish protein
• Fungi (mold)
• Wood dust
• Vapors, gases, dusts, mists, sprays or fumes from industrial materials
• Cleaning products
• Dust mites
• Indoor air pollution due to poor ventilation
• Outdoor air pollution and smog (for outdoor workers)

Tips for prevention

Activated carbon air cleaners can help
remove airborne chemicals and vapors.

Employers can and should do a number of things to improve indoor air quality at the workplace and help protect workers from exposure.

If possible, the asthma-causing or –aggravating substance should be eliminated from the workplace or replaced by a less hazardous substance.

Employers and managers can introduce helpful policies, procedures, safe work practices and job rotation to minimize workers’ exposure. This includes providing personal protective equipment when needed.

To control the exposure, think about closed-off areas where hazardous agents may be released into the air, improved ventilation systems and air cleaners to contain gases and vapors at the source.

Monitoring the exposure levels and training employees are other important steps.

On the other side, employees, too, need to work together with their employers to make sure the workplace is as safe and healthy as possible. They should also be aware of the symptoms of occupational asthma and report any health issues promptly.

Source: MRO Magazine

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Styrene: A brief look into plastics, issues and concerns

Styrene is often used in the
manufacturing of boats.

Styrene is a widely used chemical for making plastic materials. It is a main ingredient in polystyrene, acrylonitrile butadiene styrene, synthetic rubber, paints, expanded polystyrene and in hard or foam resins.

Because it resists corrosion and makes for strong materials, styrene is often used in the manufacture of marine watercraft, cultured marble countertops, solid-surface products in bathrooms and kitchen and more.

It is often applied with a bucket and roller or sprayed on and it has a strong odor, which means regulators see it as a potentially harmful substance to workers.

In June 2011, styrene was listed as a substance “reasonably anticipated to be a human carcinogen” in the 12th Report on Carcinogens in the United States.

What is styrene?

Styrene is also known as ethenylbenzene or vinyl benzene. It is an organic compound with the chemical formula C6H5CH=CH2.

Styrene is listed as "reasonably
anticipated" to be a carcinogen.

Styrene started being commercially produced in 1925 in Germany. Today, about 15 billion lbs. of styrene are produced internationally.

People are usually exposed to styrene by inhaling the fumes.

The open molding operations in the composites manufacturing industry are causing the greatest occupational exposure to styrene.

Wearing a respirator suitable for organic vapors can reduce styrene exposure but does not eliminate it entirely.

The industry’s safe-exposure limit for styrene is 50 ppm (parts per million) over an eight-hour day.

Since styrene’s listing in the 12th RoC, there have been considerable industry efforts to have the chemical delisted.

Source: Composites Technology 

Carbon air scrubbers for airborne chemicals and vapors

Activated carbon or
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