NATURALLY DANGEROUS: Surprising Facts About Food, Health, and the Environment.
By James P. Collman, Professor of Chemistry, Stanford University
Chapter 9. Dust, Magnets, and Scuba Diving
© James P. Collman, 2003. All rights reserved
In chapter 8, the role of various green house gases in causing global warming is discussed, but another important “gas” involves aerosols – a carbon containing haze that can also influence the climate. These brown clouds can shield the earth from the sun, which is a cooling effect; alternatively the soot particles in brown clouds can absorb light (of every wavelength) and re-emit that energy as infrared radiation (heat waves), which warms the air. The mathematical models used to predict global climate are incapable of calculating the effects and magnitude of these brown clouds, even though they are very important contributors to climate-change. Of course such small particles can damage your lungs and are also a health hazard. But where do carbon containing aerosols come from? There are two principal sources: incomplete combustion of biomass and fossil fuels. Biomass burning mostly results from fires due to slash burning in agriculture and forestry (the latter includes forest fires). The other tiny soot particles are produced by diesel engines and heating with coal (mostly from poorly controlled power plants). A method of distinguishing these carbon particles is to examine the amount of the radioactive carbon-14 isotope in the aerosol. Fossil fuels such as coal or diesel derived from petroleum are ancient forms of carbon and contain very little carbon-14 because it has decayed; whereas biomass (grass, wood, etc.) has recently been derived from photosynthesis and contains the contemporary level of carbon-14. (Science, 23 January, 2009, Vol. 323, pages 470 and 495)
The night sky is meant to be dark; there are consequences about nighttime lights. The convenience of artificial lights is counterbalanced by problems associated with the fact that we and many other creatures are naturally diurnal (being active in the daytime). The benefits of artificial lights come with negative consequences, referred to as light pollution. One disadvantage is seeing the stars in a dark night; this view can be dimmed, by the distant lights of a neighboring city, and reflection of clouds. Unless you are a professional astronomer, such light pollution is an esthetic problem. But important biological problems occur when naturally nocturnal species are exposed to unnatural lights at night. Light is an important biological force. The simplest examples involve birds, which go to branches of trees or their nests to spend the night, but birds are attracted by light in the night. Migrating birds are known to collide with brightly lit tall buildings; songbirds and seabirds are captured by searchlights on land or flares from oil platforms, circling in flocks until they drop from exhaustion. Some birds, such as blackbirds and nightingales sing when stimulated by artificial light. Bird's migration patterns are influenced by artificial lights, thus interfering with this precisely timed behavior.
Insects that naturally come out in the dark, are attracted to and swarm around streetlights, and attract bats, who feed on them.
Nocturnal mammals, such as desert rodents, opossums, and badgers forge in the night, relatively safe from predators. Sea turtles are attracted to dark beaches where they nest. Their hatchlings are confused by artificial light that may be reflected on the beach. It is estimated that in Florida several hundred thousand hatchlings are lost each year because of artificial light.
Darkness may be essential to humans' biological welfare. Recall that nurses working at night tend to have a higher instance of breast cancer. One possibly related new study indicates a correlation between nighttime brightness in the neighborhood and higher rates of breast cancer. It may be that production of the sleep hormone, melatonin is related to this situation? (National Geographic, November 2008)
New evidence involving identical twins has confirmed old evidence that exposure to UV sunlight gives some protection against the nerve damaging immune malfunction called multiple sclerosis (MS). From epidemiological evidence it had long been known that people living in Africa showed little tendency to develop MS. For example this disease is virtually unknown among people living in central Africa but is more prevalent among Scandinavians. But these data do not specifically implicate the role of exposure to strong sunlight. These differences might be caused by genetic factors. Now comes a definitive study of identical twins in which one twin in each pair has MS and the other twin does not. A large study involving 179 sets of such twins shows that the twin that had exposure to the sun had a 25 to 57 percent lower risk of developing MS. Moreover, this protective effect of UV sunlight appears to be limited to exposure before adulthood. The mechanism by which strong sunlight affects the immune system is unclear, but the effect is real and is startling. (Science News, July 28, 2007, Vol 172, Page 51)
There are approximately 1,500 active volcanoes on Earth and about 600 erupt each year. Some of these throw ash clouds high in to sky, so high that the particles can endanger commercial aircraft. It is estimated that there such a hazard occurs about 25 days in every year. A December 15, 1989 KLM flight from Amsterdam to Anchorage Alaska flew into such a volcanic dust cloud and had all four engines die so that only battery power remained to restart the engines. After falling more than 2 miles, the pilots were able to restart the engines and landed the plane safely in Anchorage, but the aircraft suffered $80 million damage, requiring four new engines and a paint job. In the past 20 years more than 90 airplanes have flown through such volcanic clouds. A warning system is now in place to reduce these hazards. (Science News, September 13, 2003, Vol. 164, page 168)
Australian beaches are a sun worshiper's paradise, but exposure to such strong sunlight results in more melanin production and a tanned appearance from this pigment, but there is a downside to suntans: the sun's rays can cause skin cancer. Basal cell and squamous cell skin cancers are more common, but these are easier to treat. Melanoma skin cancers are much more serious, tend to spread to other tissues (metastasize) and can become life threatening, even to young adults. Twenty-five years ago, exposure to the strong Australian sun was giving rise to increasing cases of melanoma. To shift the attitudes of young Australian beachgoers, a TV ad featuring "Sid the Seagull", introduced the phrase: Slip! Slop! Slap! which translates: put on a shirt, slop on plenty of sunscreen, and slap on a hat. This ad has had a positive effect in lowering skin cancer rates in Australians. I would have said: Slop! Slip! Slap! Who wants to put tanning lotion over a shirt? (Mayo Clinic Health Letter, volume 24, Number 4, April 6, 2006)
There is an apparent warming in the Arctic, more so than other regions on Earth. This accelerated heating is a feedback from the overall modest global warming observed in other regions of the Earth. The mechanism for additional warming in the Arctic stems from a phenomenon that scientists call the albedo effect. Perhaps you have observed that you are warming on a sunny day when wearing blue or dark clothing. Recall that the Bedouins wear white, not dark robes in the desert. Dark materials absorb visible light, whereas white objects reflect light. As darker items absorb more solar radiation than lighter ones do, dark materials become warmer. When snow melts in the Arctic, dark shrubs and tundra appear. As a result a cooler area becomes warmer. This self-amplifying albedo effect appears to be the primary cause of the recent warming in the Arctic, accounting for about 95 percent of the heating observed in Alaska. Average summer temperatures in Alaska and Western Canada have increased by about 1.4 degrees C, nearly 3 degrees Fahrenheit since 1961, whereas average temperatures have risen only about 0.6 degrees Centigrade worldwide. As the snow and ice melt, the landscape becomes darker and warmer, but only if the average temperatures in the Spring and Fall are near freezing. This situation occurs in much of the Arctic. (Science News, November 12, 2005, Vol. 168, page 312)
A study has been made of the ultra fine diesel particles (DPM) in diesel powered school buses in Berkeley and Los Angeles. Recall from Chapter 9 in Naturally Dangerous that ultra fine carbon particles are known to be a risk factor for cancer. These studies found that children riding in these school buses (models from 1985 – 2002) inhaled 34 to 70 percent more DPM than did the average weekday commuter during the same day. Newer school buses are a little better, but the entire fleet should be improved. Ironically riding in individual cars is less safe than a school bus because the buses are very well built: “like a tank”. New York Times, April 26, 2005, page D6)
A recent statistical study funded by the National Institutes of Health has found evidence that small soot particles, such as those from coal-fired power plants and diesel engines, are linked to certain types of heart disease and premature deaths. It is thought that soot particles imbedded in lung tissue produces inflammation, which induces clogging of the arteries and heart attacks. The degree of danger is calculated to be greater than deaths from lung cancer. This idea connects with several studies suggesting that inflammation can induce the formation of fatty plaques and is more serious than high levels of LDL, the bad cholesterol. The most dangerous particles are those less than 2.5 microns in diameter, which you will learn from page 197 in Naturally Dangerous, is less than one-twentieth the diameter of a human hair. Soot particles can contain several toxic substances such as arsenic, mercury, cadmium, and lead. There is some good news: because of air pollution laws and industrial improvements air pollution from soot has decreased by one-third over the past 20 years. Recently introduced legislation has reduced soot emissions from diesel
In Naturally Dangerous it is pointed out that artificial tanning with ultraviolet light can cause melanoma, a rare but deadly form of skin cancer. This practice is even more dangerous according to an article in the Journal of the National Cancer Institute, February 6, 2002, which reports that clients of artificial sunbathing are susceptible to other types of skin cancer. They are 1.5 times as likely to have basal-cell carcinoma and 2.5 times as likely to have squamous-cell carcinoma compared with individuals who never participated in such unnatural indoor tanning. Young people are even more susceptible; for those under 20 years old, for these the risks increase to 1.8 and 3.6 times the basic risk. As mentioned in Chapter 5, most cancers are diseases of old age, but skin cancers can strike and kill young adults, who believe themselves to be invincible. That peculiar trait may also explain why young people smoke.
The myth of magnetic effects continues to grow. A magnetic device, “the Perfect Sommelier” is claimed to age wine in 30 minutes, “without changing its personality”. Wine tasting anyone? It is difficult to believe that adults would waste their money this way until you read the following. An ad in the mail promotes the “Fuel Optimizer”. This magnetic device, when positioned over your car’s fuel line is said to break apart clusters of fuel molecules sot gas burns more efficiently. I hope you haven’t taken out your checkbook. Such scientific fraud is apparently legal.