Tonight, after returning home after a very long week, I decided to unwind and relax by reading about morbidity, mortality and risk associated with air pollution, not the serious form of air pollution represented by climate change inducing gases, but the less serious kind that only kills two million people per year, chiefly - but not limited - to particulate matter from combustion. Many people know of course, that combustion products, of which tobacco smoke is only a relatively minor example - contain a mixture of highly carcinogenic compounds, and many major inorganic irritants, represented by oxides of sulfur, nitrogen, and, if you will, an "oxide" of oxygen, ozone.
Another risk associated with air pollution is cardiovascular disease. An interesting commentary related to this topic - here with respect to the incidence of stroke in connection with air pollution - is found in the Journal of the American Medical Association, (Matteen and Brook, JAMA, JAMA, March 23/30, 2011—Vol 305, No. 12, 1240-1241) contained this interesting tidbit:
Although the public health burden of air pollution–related stroke is significant in high-income countries (in which pollution levels have declined over past decades), the health effects associated with air pollution may be most important in developing countries, where approximately 85%of the world’s population lives. Thirteen of the world’s megacities(10 million inhabitants) are located in tropical regions. Biomass burning (affecting 3 billion individuals worldwide) has been estimated as the sixth leading contributing factor for death in developing countries.1Not to worry. Biomass burning is, um, renewable energy, and therefore it's good, unless of course you're one of the 3 billion people on this planet who reside in areas that never joined in the abandonment, by the richer 10 or 20 percent of the world's cultures, of renewable energy in the early 19th century in favor of coal driven steam - which is now more widely used than ever before, as well as ultimately (largely in the 20th century) petroleum and natural gas. Today there's a certain kind of reactionary enthusiasm for returning to the old "natural" ways.
Split wood, not atoms, cough, cough, cough.
I oppose all dangerous fossil fuels, if you must know, and often demand an end to them, not that anyone on the planet gives a rat's ass what I demand. The world is using the largest amounts ever not only of coal, as mentioned above, but also of petroleum and natural gas.
As of 2010, world consumption of oil was 85,710,000 barrels per day, just slightly short of the all time record set in 2007. The 2010 world consumption of coal was 7.994 billion short tons, an all time record (until we find out what the figures for 2011 are) and up by nearly three billion tons from the turn of the last century in 2000. Natural gas burning and waste dumping produced 119 Quads (125 exajoules) of energy in 2010, also an all time record, up from 91 Quads, (96 exajoules) in 2000.
Heckuva job fighting climate change humanity! Don't worry. Be happy. Split wood, cough, cough, not atoms.
Enough of that. Anyway.
I meant to pull up and collect reference (1) in the above citation, which is a reference to N Engl J Med. 2010;363(13):1196-1198, but I got distracted by an electronic monograph which I downloaded in its entirety, entitled "Urban Airborne Particulate Matter: Origin, Chemistry, Fate and Health Impacts." (Zereini, Wiseman, Eds, Springer-Verlag, 2010)
This is a diary about particulate palladium volatilized out of catalytic converters in cars, which seemed to be a big topic in this book about the air pollution that is classified under the general rubric of "particulate matter."
When I was a kid and lived in Hermosa Beach, California - which was then a town for dirty hippie low lifes like me, but was sometime later "gentrified" into an upscale suburban beachfront nirvana for rich people - there used to a bookstore on Pier Avenue, called "The Either/Or Bookstore."
It's gone now. A whole world is gone now.
"The Either/Or Bookstore" had wonderful literature and poetry, and all sorts of "Whole Earthy" kinds of books about how to be a great wholesome vegetarian, how to become a Zen/WuLi/Tibetany/Bhuddisty/Hinduisty/Wiccan/Horoscopedly spiritually fullfilled dye free and additive free citizen of the New Age.
I really loved that store, and if you must know bought lots and lots and lots of books there, mostly poetry and far out literature, even though at the time, I often really had to struggle to have enough money to buy a bag of rice.
The Either/Or Bookstore had postcards, some of the beach, of surfers, that sort of thing but also some featuring LA smog. These cards showed aerial views of the brown inversion layer hanging over the city and under the mountains. The text of the card was all about the the number of cars in the LA basin, and if I recall correctly, a rather accurate description of the chemistry of smog. Other than books about how to make LSD, or psilocybin in your bathtub, this was probably the only chemistry available to read in the "Either/Or" bookstore. (I couldn't have cared less, since I was totally uninterested in chemistry at the time: I knew so little about science in those days that I could have qualified for membership in Greenpeace.)
In those days, and I think, even in these days, you could stand on the shore in Hermosa Beach, or Manhattan Beach, and watch the layer of brown smog flow out to sea just under the Santa Monica Mountains. The brown colored stuff was actually only one of the multitude of pollutants associated with cars: It was (and is) nitrogen dioxide, NO2. Although nitrogen is generally inert, under pressure and at high temperatures - such as is found in the compression and ignition strokes in internal combustion engines, nitrogen burns. The product is nitrogen monoxide (NO) as well as nitrogen dioxide, the former rapidly oxidizes in air to the latter. Nitrogen dioxide can react further with air and water to form nitric acid, and this is a constituent, along with sulfuric acid formed by burning sulfur in petroleum and coal, of so called "acid rain."
Since the late 19th century, chemists knew that the platinum group elements, the elements platinum, palladium, rhodium, osmium, iridium and ruthenium all catalyze the destruction of nitrogen monoxide and nitrogen dioxide into their constituent elements, which of course, simply make up the bulk of "normal" air. Further these elements - particularly the first three I listed - also catalze the oxidation of carbon monoxide, another poisonous constituent of internal combustion engines, into the famous greenhouse gas carbon dioxide, which despite its greenhouse effects, is generally considered nontoxic.
However platinum - which is much more expensive (and rarer) than gold - was thought to be too expensive to be utilized in cars until chemists at General Motors found a way to use relatively little of it to coat the surface of certain cheap oxides having certain particle shapes - alumina was the first oxide to be used in this way - so that relatively small masses of platinum could have a large surface area.
This cut, but did not eliminate the nitrogen oxide problem with cars, and eventually, in the 1970's was mandated on all new cars. With further tinkering, catalytic chemists at automotive companies began to toy with even cheaper catalysts, adding cheaper (but still expensive) palladium, with very small amounts of rhodium to make ever more efficient catalysts. Of the three metals, palladium is the cheapest, and by 2008, catalytic converters began to appear on the market that contiained only palladium.
Whoopie! We're saved!!!! We can have guilt free cars, well, um, sort of...
A whole world is gone now.
By the way, the nitrogen oxides that escaped (and still escape) from cars ultimately end up, largely through biotransformation, as nitrous oxide (N2O) - which is also a by product of the fertilization of agricultural and ornametal crops. Eventually the ozone depleting (and greenhouse gas potential) effects of nitrous oxide will make the CFC problem into a relative walk in the park, but don't worry. Be happy.
Apparently, however, the palladium catalyst is not risk free. Given the noxious nature of nitrogen oxides, we can say that palladium catalysts are risk minimized but not risk free.
There is no such thing as risk free energy. It doesn't exist. It will never exist.
It appears that palladium particulates are widely distributed all around the earth.
Here's an excerpt in the "Urban Airborne Particulate Matter" monograph, from a chapter called, "Analysis of Palladium Concentrations in Airborne Particulate Matter
with Reductive Co-Precipitation, He Collision Gas and ID-ICP-Q-MS":
Platinum group elements (PGE) are used as catalysts in a variety of industrial, chemical and pharmaceutical applications, such as in the production of pesticides and dye stuffs and in the processing of polymers. These rare noble metals, notably platinum (Pt), rhodium (Rh) and palladium (Pd), are also used as catalysts in automobile catalytic converters to reduce the emission of carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC) in exhaust fumes. This application, in fact, accounts for the largest consumption of the global supply of these metals on a per weight basis. In 2008, for instance, catalytic converter producers consumed a total of 52, 47 and 86% of the world’s Pt, Pd and Rh, respectively (Matthey 2008). Pd use by the catalyst industry increased by a factor of six from 1993 to 2008 (Matthey 1996, 2008). While the noxious by-products of fossil fuel combustion are significantly reduced in automotive exhausts, PGE are also released in small amounts together with particles from the wash coat of the converters, due to fast changing oxidative and reductive conditions, high temperatures and mechanical abrasion of the catalytic material (Schlögl et al. 1987; Artelt et al. 2000). This has led to increasing concentrations of these metals in the environment since the introduction of catalytic converters in Europe in the 1980s and elsewhere, as has been documented in a number of studies (e.g. Zereini et al. 1997, 2007; Whiteley and Murray 2003; Limbeck et al. 2004; Rauch et al. 2005; Figueiredo et al. 2006; Jarvis et al. 2001; Gómez et al. 2003). It has generally been assumed that the concentrations of these metals in the environment are too low to pose a real risk to human health (Wiseman and Zereini 2009; Colombo et al. 2008). For instance, Pd concentrations in airborne PM sampled in various cities have generally been found to be present in the low pg/m3 range (Zereini et al. 2004, 2005; Limbeck et al. 2007; Iavicoli et al. 2008). Recent evidence suggests, however, that the environment and health risks of exposures to these metals are greater than once thought (Wiseman and Zereini 2009). In particular, there are concerns regarding significant increases in the concentrations of Pd in the environment during the last decade due to the introduction of a three-way catalytic converter as an alternative to the conventional ones using Pt and Rh. Pd may pose a greater environmental and human health risk given its apparent greater solubility (Jarvis et al. 2001) and increased bioavailability and uptake by organisms (Colombo et al. 2008; Turner and Price 2008).The rest of the paper is about analytical chemistry, the methods of inductively coupled plasma mass spectoscopy, (ICP-MS) which is a very sensitive method of detecting metals in the environment and elsewhere.
I'm not really, by the way, all that concerned about the distribution of palladium in the environment personally. It may be harmful to some extent, and it may actually also have certain benefits, particularly with respect to various kinds of other air pollutants, the ones that kill regularly and constantly, albeit with very little comment compared to say, mildly radioactive spinach in Japan.
Interesting though, I think...
Have a great day tomorrow.