Archive for January, 2010

N95 respirator and surgical mask are similarly protective against influenza

Wednesday, January 27th, 2010

Clinical question How effective is the surgical mask compared to the N95 respirator in protecting health care workers against influenza?

Bottom line Laboratory-confirmed influenza occurred with similar incidence among nurses wearing a fit-tested N95 respirator compared with a standard surgical mask when caring for patients with febrile respiratory illness. Given the increased expense and greater discomfort with use of the N95 respirator compared with the surgical mask, this information should be very helpful for the coming influenza season. (Level of evidence = 1b)

Synopsis Real world evidence comparing different respiratory protective devices is sparse. These investigators randomized (concealed allocation assignment) 446 nurses working full time in emergency departments, medical units, and pediatric units from eight medical centers in Canada to either a fit-tested N95 respirator or surgical mask when providing care within one meter of patients with febrile respiratory illness. The primary outcome measured was laboratory-confirmed influenza. Personnel conducting confirmatory testing for influenza illness remained blind to intervention group assignments. Study subjects wore gloves and gowns when caring for patients with suspected infection. About 30% in each group received influenza vaccine during the study year. Complete follow-up occurred for more than 90% of participants. Using intention-to-treat analysis, laboratory-confirmed influenza occurred with similar incidence in both the surgical mask and N95 respirator group (23.6% vs 22.9%, respectively). In addition, there was a nonsignificant trend for an increased incidence of the specific pandemic H1N1 swine influenza strain in the N95 respirator group compared with the surgical mask group (11.9% vs 8.0%). Using per-protocol analysis with only data from subjects with complete follow-up there was still no significant difference in influenza illness between the two intervention groups. The study was 80% powered to detect a 10% risk reduction with the N95 respirator.

Loeb M, Dafoe N, Mahony J, et al. Surgical mask vs N95 respirator for preventing influenza among health care workers: a randomized trial. JAMA. 2009;302(17):1865-1871. doi:10.1001/jama.2009.1466. Published October 1, 2009. 

Plastic Bottle Recycling Facts

Monday, January 25th, 2010

Plastic bottles can be recycled into: rugs, swimming goggles, dog bowls, back packs, skateboard wheels, and ski jackets.

 

- Plastic bottles are very fashionable: about five plastic bottles produce enough fiber filling for a ski coat, 25 recycled bottles can make a fleece coat, and it takes 26 bottles to make a polyester suit.

 

- It takes 14, 20-ounce PET bottles to produce one Extra Large T-shirt.

 

- Amazing Recycled melts plastic and whips it in an electric mixer, making a foam. The foam is spun into fibers. They take the fibers, mix it with cotton and make white T-shirts that are 50% cotton/50% water bottles.

 

- Made from recycled plastic, the nails and screws in plastic lumber hold better than wood for at least 50 years.

 

- A one liter water bottle can be recycled and manufactured as a ruler.

 

- The filling for one sleeping bag could be made from 85 20-ounce water bottles.

Recycling of different plastics

Thursday, January 14th, 2010

The confusion over what we can and cannot recycle continues to confound consumers. Plastics are especially troublesome, as different types of plastic require different processing to be reformulated and re-used as raw material. Some municipalities accept all types of plastic for recycling, while others only accept jugs, containers and bottles with certain numbers stamped on their bottoms.

Recycling by the Numbers
The symbol code we’re familiar with—a single digit ranging from 1 to 7 and surrounded by a triangle of arrows—was designed by The Society of the Plastics Industry (SPI) in 1988 to allow consumers and recyclers to differentiate types of plastics while providing a uniform coding system for manufacturers.

The numbers, which 39 U.S. states now require to be molded or imprinted on all eight-ounce to five-gallon containers that can accept the half-inch minimum-size symbol, identify the type of plastic. According to the American Plastics Council, an industry trade group, the symbols also help recyclers do their jobs more effectively.

Easy Plastics to Recycle
The easiest and most common plastics to recycle are made of polyethylene terephthalate (PETE) and are assigned the number 1. Examples include soda and water bottles, medicine containers, and many other common consumer product containers. Once it has been processed by a recycling facility, PETE can become fiberfill for winter coats, sleeping bags and life jackets. It can also be used to make bean bags, rope, car bumpers, tennis ball felt, combs, cassette tapes, sails for boats, furniture and, of course, other plastic bottlesPET bottle recycling.

Number 2 is reserved for high-density polyethylene plastics. These include heavier containers that hold laundry detergents and bleaches as well as milk, shampoo and motor oil. Plastic labeled with the number 2 is often recycled into toys, piping, plastic lumber and rope. Like plastic designated number 1, it is widely accepted at recycling centers.

Plastics Less Commonly Recycled
Polyvinyl chloride, commonly used in plastic pipes, shower curtains, medical tubing, vinyl dashboards, and even some baby bottle nipples, gets number 3. Like numbers 4 (wrapping films, grocery and sandwich bags, and other containers made of low-density polyethylene) and 5 (polypropylene containers used in Tupperware, among other products), few municipal recycling centers will accept it due to its very low rate of recyclability.

Another Useful Plastic to Recycle
Number 6 goes on polystyrene (Styrofoam) items such as coffee cups, disposable cutlery, meat trays, packing “peanuts” and insulation. It is widely accepted because it can be reprocessed into many items, including cassette tapes and rigid foam insulation.

Hardest Plastics to Recycle
Last, but far from least, are items crafted from various combinations of the aforementioned plastics or from unique plastic formulations not commonly used. Usually imprinted with a number 7 or nothing at all, these plastics are the most difficult to recycle and, as such, are seldom collected or recycled. More ambitious consumers can feel free to return such items to the product manufacturers to avoid contributing to the local waste stream, and instead put the burden on the makers to recycle or dispose of the items properly.

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Seven Misconceptions about Plastic and Plastic Recycling

Monday, January 4th, 2010

Plastic Recycling

Misconception # 1: Plastics that go into a curbside recycling bin get recycled. Not necessarily. Collecting plastic containers at curbside fosters the belief that, like aluminum and glass, the recovered material is converted into new containers. In fact, none of the recovered plastic containers from Berkeley are being made into containers again but into new secondary products such as textiles, parking lot bumpers, or plastic lumber – all unrecyclable products. This does not reduce the use of virgin materials in plastic packaging. “Recycled” in this case merely means “collected,” not reprocessed or converted into useful products.

Misconception # 2: Curbside collection will reduce the amount of plastic landfilled. Not necessarily. If establishing collection makes plastic packages seem more environmentally friendly, people may feel comfortable buying more. Curbside plastic collection programs, intended to reduce municipal plastic waste, might backfire if total use rises faster than collection. Since only a fraction of certain types of plastic could realistically be captured by a curbside program, the net impact of initiating curbside collection could be an increase in the amount of plastic landfilled. The Berkeley pilot program showed no reduction of plastic being sent to the landfill in the areas where the curbside collection was in operation. Furthermore, since most plastic reprocessing leads to secondary products that are not themselves recycled, this material is only temporarily diverted from landfills.

Misconception # 3: A chasing arrows symbol means a plastic container is recyclable. The arrows are meaningless. Every plastic container is marked with the chasing arrows symbol. The only information in the symbol is the number inside the arrows, which indicates the general class of resin used to make the container. The attorneys general of 11 states objected to false and misleading claims about plastic recyclability. The recent settlement that they reached with the American Plastics Council paves the way for a first-ever definition of what claims can or cannot be made about plastic recycling and recyclability.

Misconception # 4: Packaging resins are made from petroleum refineries’ waste. Plastic resins are made from non-renewable natural resources that could be used for a variety of other applications or conserved. Most packaging plastics are made from the same natural gas used in homes to heat water and cook.

Misconception # 5: Plastics recyclers pay to promote plastics’ recyclability. No; virgin resin producers pay for the bulk of these ads. Most such ads are placed by virgin plastic manufacturers whose goal is to promote plastic sales. These advertisements are aimed at removing or diminishing virgin plastic’s greatest challenge to market expansion: negative public conception of plastic as unrecyclable, environmentally harmful, and a major component of wastes that must be landfilled or burned.

Misconception # 6: Using plastic containers conserves energy. When the equation includes the energy used to synthesize the plastic resin, making plastic containers uses as much energy as making glass containers from virgin materials, and much more than making glass containers from recycled materials. Using refillables is the most energy conservative.

Misconception # 7: Our choice is limited to recycling or wasting. Source reduction is preferable for many types of plastic and isn’t difficult. Opportunities include using refillable containers, buying in bulk, buying things that don’t need much packaging, and buying things in recyclable and recycled packages

Plastic packaging has economic, health, and environmental costs and benefits. While offering advantages such as flexibility and light weight, it creates problems including: consumption of fossil resources; pollution; high energy use in manufacturing; accumulation of wasted plastic in the environment; and migration of polymers and additives into foods.

Plastic container producers do not use any recycled plastic in their packaging. Recycled content laws could reduce the use of virgin resin for packaging. Unfortunately, the virgin&endash;plastics industry has resisted such cooperation by strongly opposing recycled -content legislation, and has defeated or weakened consumer efforts to institute stronger laws. Plastic manufacturers recently decided that they will not add post consumer materials to their resins used in the USA.

There is a likelihood that establishing plastics collection might increase consumption by making plastic appear more ecologically friendly both to consumers and retailers. Collecting plastics at curbside could legitimize the production and marketing of packaging made from virgin plastic. Studies of garbage truck loads during the recent plastic pick-up pilot program showed no reduction of “recyclable” plastic containers being thrown away in the pilot areas (in fact, there was a slight increase). Due in part to increased plastic use, glass container plants around the country have been closing, including Anchor Glass Container Corporation in Antioch, putting 300 people out of work

Plastic recycling costs much and does little to achieve recycling goals. Our cost/benefit analysis for implementing curbside plastics collection in Berkeley shows that curbside collection of discarded plastics: involves expensive processing; has limited benefits in reducing environmental impacts; and has limited benefits in diverting resources from waste.

Processing used plastics often costs more than virgin plastic. As plastic producers increase production and reduce prices on virgin plastics, the markets for used plastic are diminishing. PET recyclers cannot compete with the virgin resin flooding the market.

Increasing the capture rates of glass, paper or yard debris in Berkeley could divert more resources from landfills than collecting plastics at curbside. The “recyclable” plastic to be collected in Berkeley at most would only amount to 0.3% of the waste stream.

Five Strategies to Reduce the Environmental Impact of Plastics

1. Reduce the use
Source reduction Retailers and consumers can select products that use little or no packaging. Select packaging materials that are recycled into new packaging - such as glass and paper. If people refuse plastic as a packaging material, the industry will decrease production for that purpose, and the associated problems such as energy use, pollution, and adverse health effects will diminish.

2. Reuse containers
Since refillable plastic containers can be reused about 25 times, container reuse can lead to a substantial reduction in the demand for disposable plastic, and reduced use of materials and energy, with the consequent reduced environmental impacts. Container designers will take into account the fate of the container beyond the point of sale and consider the service the container provides. “Design for service” differs sharply from “design for disposal”.

3. Require producers to take back resins
Get plastic manufacturers directly involved with plastic disposal and closing the material loop, which can stimulate them to consider the product’s life cycle from cradle to grave. Make reprocessing easier by limiting the number of container types and shapes, using only one type of resin in each container, making collapsible containers, eliminating pigments, using water-dispersible adhesives for labels, and phasing out associated metals such as aluminum seals. Container and resin makers can help develop the reprocessing infrastructure by taking back plastic from consumers.

4. Legislatively require recycled content
Requiring that all containers be composed of a percentage of post-consumer material reduces the amount of virgin material consumed.

5. Standardize labeling and inform the public
The chasing arrows symbol on plastics is an example of an ambiguous and misleading label. Significantly different standardized labels for “recycled,” “recyclable,” and “made of plastic type X” must be developed.