Thursday, May 28, 2009
What is Nanotechnology?
Nanotechnology is the use of engineered structures which are on the size of a nanometer to potentially up to hundreds of nanometers.
- First the size issue: a nanometer is one billionth of a meter - less than the wave length of a wave of visible light. A particle of ragweed pollen is about 20,000 nanometers. From a size perspective, it is easy to see that this technology must be intricate to form such minuscule structures that can perform a useful purpose or operation.
- Second, what is an engineered structure? Engineered refers to designed and built according to a specification or specific architecture. A structure can be of many forms, from performing as a shield to acting as a conductor to acting as a miniature engine.
These structures can be thought of in a different manner - think of a structure that is built up atom by atom to make that structure. It is interesting to note that some elements when taken as an atom act in a wholly different fashion than when they are formed in large molecules.
Bottomline: nanotech structures are small but complex, potentially may have versatile applications but potentially unpredictable for what we currently know, and can be thought of as "designer" structures.
Possible applications: Scratch-resistant coatings using aluminum silicate, antimicrobial bandages or odor-eating socks using silver nanoparticles, smaller computer processors, and medical treatments/"drugs" which target deleterious (e.g., cancer) cells.
So what are some of the environmental impacts?
Let's take the example of silver nanoparticles to fight odor in socks. It sounds like a great idea. What happens to those particles when you wash the socks? Likely some of those particles will be released into the environment or washed into the local waste water treatment plants. If the silver nanoparticles kill odor-producing bacteria in socks, what will happen to the good bacteria used in waste water treatment plants? Will these plant become less effective? Do these type of nanoparticles have the potential to become a new type of DDT which targets useful bacteria or other microbes?
As I mentioned above some of these particles can act in an unexpected manner. With a proliferation of these tiny particles, could there be a risk of toxic effects to humans and other flora and fauna in the biosphere. With the small size of these particles, they could cross the blood-brain barrier and have toxic effects. Similar effects could be possible in other animals as well as in the plant kingdom.
On a positive note, safe (rigorously tested) nanoparticles could be designed to reduce the need for invasive surgery or to enable doctors to more precisely excise a harmful cell from the body (i.e., could cut better than a laser scalpel).
What are two of the major pollution or overconsumption issues that we face today? We overuse energy (use fossil fuel plants for electricity) and overuse water. Why bring this up with respect to nanotechnology? Think about how nanoparticles can be made. By making a particle using a top-down (lithography) or bottom-up (atomic layer deposition) approach, you can imagine that the process is likely to be energy-intensive. Certain precipitation manufacturing techniques are also water-use intensive. The water used in the process could then be contaminated or polluted with other chemicals or solvents used during the nanoparticle processing. So there exists a possibility that we are creating significant amounts of waste as well as using significant amounts of energy to manufacture nanoparticles.
With the newness of this technology, there are many unanswered questions, including whether or not the benefits of nanotechnology outweigh the potential harmful effects on the environment. With any new technology or product, care must be taken to do due diligence and take a systematic approach to examining the effects. We don't want to unleash a product which we think provides a great benefit but then we find out we have poisoned ourselves, like our history with DDT.
Sunday, April 12, 2009
The debate goes back to whether having grass or having a bed/garden is environmentally better. Don't people say that gras takes more time to maintain than plants or a garden?
Let's think about it in another way.
Which contributes less towards global warming - grass or garden/plant bed?
Is having grass actually a carbon sink?
To maintain a typical lawn, you have to do the following:
- Mow it weekly.
- Fertilize it 2-3 times per year.
- Trim or 'weed whack' weekly.
- Dethatch, aerate, and overseed which may be done with a gas-powered unit.
- Blow leaves in the fall.
- Apply herbicides for weed control
With the mowing, trimming and watering, along with the energy it takes to produce the fertilizer and herbicides, it is easy to conceive that having grass may not actually prove to be a carbon sink. With the energy use or carbon dioxide produced in taking care of the lawn, it may be more than the actual grass uses for photosynthesis.
How can you minimize your lawn care foot print:
- Use a manual, 'old fashioned' mower
- Keep grass length at about 4 inches - reduces water needs and chokes out weeds
- Use organic fertilizers that minimize nitrogen content
- Manually rake leaves, spread organic fertilizer and overseed with rotary or drop-spreader, manually dethatch and aerate
- Increase your garden size or bed sizes with native plants
- Pull weeds manually or let some of them grow
- If the older generations did things manually then we can too
To maintain a bed/garden:
- Plant a plant - locally grown food will save transport costs of shipping tomatoes from across the country native species of woody plants can be a carbon sink and be abel to handle local weather conditions.
- Mulch - save on watering and decrease weeds, lessening the need for herbicides.
- Perhaps fertilize and water (depending on the plant) - use organic fertilizers or soil mixes to promote plant growth.
- Clean the beds - use manual rakes to minimize the use of trimmers and blowers.
Friday, March 6, 2009
Ever since Rachel Carson's Silent Spring we have been awoken to the possibility that our impacts on the environment may be harmful and not sustainable. With the world's population growing and a greater demand on natural resources, what have been some of our impacts?
- Loss of biodiversity - More endangered species
- Global Warming
We have proven, as a world culture, that we can take a more environmentally friendly route and work towards a more sustainable society:
- Reduction in ozone destroying pollution
- Reduction in the use of harmful pesticides
Where do we go from here?
What technology will we develop in the future?
How sustainable will those technology options be?
Some of our choices:
- Wind vs Coal vs Solar vs Nuclear vs Natural gas
- Hybrid vs Diesel vs Gas vs Electric vs Hydrogen cars
- Paper vs Plastic
- CFLs vs LEDs
- Biodiesel vs Diesel/Gas
- Vampire Loads
- McMansion vs not
- Commercial vs Organic fertilizer
- Construction materials: Concrete vs Wood vs Metal vs Plastic
- Gas-powered vs electric appliances