# Do the Smoky Mountains get their name from the pollution produced by all the trees? **URL:** \ **Category:** Great Debates\ **Created:** [March 21, 2003, 2:38pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091 "2003-03-21T14:38:43Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Mr.Svinlesha](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mr.Svinlesha](https://boards.straightdope.com/u/Mr.Svinlesha)\ **Post date:** [March 21, 2003, 2:38pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/1 "2003-03-21T14:38:43Z")
Introduction: Long ago, in a debate about the relative merits and faults of Ronald Reagan (which also happened to be a hijack of [**this thread**](http://boards.straightdope.com/sdmb/showthread.php?threadid=139049&perpage=50&pagenumber=2)), I made the mistake of trotting out the old saw that Reagan had once claimed “trees pollute more than heavy industry,” as evidence of his creeping dotage. **Sam Stone** responded: > [@](#): > > - > 1. Reagan did NOT say that trees pollute more than heavy industry. He said that some trees cause pollution. And he was absolutely correct. Do you know why the ‘Smokey Mountains’ are smokey?\* After providing an rather irrelevant link to support this claim, he continued:\* > [@](#): > > This is not a trivial factor. The Smokey mountains are covered by a constant haze of these types of pollutants. The pollutant emissions from certain species of trees can be a significant enough to be a health hazard. The same condition can be found in the ‘Blue Ridge Mountains’. The ‘Blue’ comes from the constant presence of ground-level ozone and hydrocarbons, emitted from the trees. Some estimates are as high as 80% of worldwide ground-level Turpene and Isoprene pollution comes from trees, not industry.\* Clearly, here, Sam is arguing that the Smoky Mountains derive their name from the pollution produced by all the trees. I found this claim ludicrous, and said as much. When I explained why, however, **Sam** failed to respond to my counter-argument, and the issue was dropped. I have avoided bringing up this embarrassment since then, out of a sense of decorum, but in [**this thread**](http://boards.straightdope.com/sdmb/showthread.php?postid=3157961#post3157941), I found myself so provoked by one of **Conan the Canadian’s** posts that I couldn’t resist reminding readers that the opinions so expressed were those of a person who also believes that the Smokies got their name from the pollution produced by the trees. To my amazement, not only did **Sam** continue to defend his claim, but others jumped in to support him. Despite the fact that there are much more important events occurring in the world, and significantly more important topics for debate, I find that I simply cannot let this question go. It irks me. It is important in part because **Sam’s** claims are terribly misleading, but also because it provides a textbook example of how scientific findings can be misconstrued to support a given political agenda – or, as seen in this specific case, can be misused to revise the historical record, by reconstructing a historical figure – Ronald Reagan – and transforming him, as it were, from the boob he truly was into a kind of “Renaissance Man of Science.” But let us start at the beginning. These are the specific statements made by Reagan on this question: > [@](#): > > \*\* “The American Petroleum Institute filed suit against the EPA [and] charged that the agency was suppressing a scientific study for fear it might be misinterpreted… The suppressed study reveals that 80 percent of air pollution comes not from chimneys and auto exhaust pipes, but from plants and trees.” – 1979 > > ”Trees cause more pollution than automobiles do." – 1981 > > “Approximately 80 percent of our air pollution stems from hydrocarbons released by vegetation, so let’s not go overboard in setting and enforcing tough emission standards from man made-sources.” – date unknown, quoted from [americanpresident.org](http://americanpresident.org).\*\* As I pointed out in the previous discussion on this issue, linked above, “80% of the world’s pollution coming from plants and trees would mean, if my math is correct, that 20% of the world’s pollution resulted from industry (and cars);” that is to say, Reagan _is_ claiming above that trees pollute more than heavy industry, precisely as I had originally posited, and _not_ that “some trees pollute,” as **Sam** would have the reader believe. Nevertheless it turns out, ironically, that there was a grain of truth to Reagan’s claims. The culprit of the story is isoprene, a hydrocarbon that is also primary ingredient in the set of chemical reactions that lead to the creation of smog. Many species of trees release isoprene – one of a group of substances known as terapenes – sometimes in large quantities. In combination with man-made nitrogen oxide (from car exhaust), isoprene can form alkyl nitrate; and alkyl nitrate, when exposed to sunlight, turns into “photochemical smog.” Hence, in a roundabout sort of way, one can claim that some trees (particularly in urban forests), in combination with man-made sources of NO, contribute to the creation of urban smog. (It was later discovered that in some instances, terapenes reacted with sunlight to create so-called “fine particles” even without the intervention of man-made NOs). On the other hand, I submit that Reagan’s claims, quoted above, are hopeless simplifications of these findings, and seriously misleading as well. Reagan used this simplification, for example, to argue against anti-pollution regulations. This is the crux of the matter. I beg the reader to keep in mind that isoprene, taken on its own, is not a pollutant. 80% of the isoprene produced by trees is oxidized into CO[sub]2[/sub]; the remaining 20% is converted into so-called “fine particles” (particles with a diameter of less than 2.5 micro-meters) of organic carbon. These particles provide the nuclei for rain, and contribute to the earth’s albedo (i.e., reflectivity). Depending on one’s definition, I suppose these products might also arguably fill the technical qualifications for “pollution,” or “smog,” but that’s stretching it a bit. This also depends on whether or not one defines smog in terms of the presence of fine particles, or in terms of the creation and presence of ozone, NO[sub]2[/sub], and PAN (peroxyacetylnitrate), which are the chemical compounds that make up smog as it is traditionally understood. (Regardless of that, **Sam’s** claim that “_The same condition can be found in the ‘Blue Ridge Mountains’. The ‘Blue’ comes from the constant presence of ground-level ozone and hydrocarbons, emitted from the trees_,” is class A disinformation – trees do not release ozone.) Finally, we must also consider quantity: do trace amounts of fine particles, ozone, NO[sub]2[/sub], and PAN in an atmospheric sampling really imply the presence of “smog,” or “pollution,” as the terms are commonly used? I submit that the isoprene emitted by trees in the Smoky Mountain biosphere does not lead to the formation of a significant “blue haze,” or to the creation of “smog pollution” up on the heights, despite “popular scientific” reports to the contrary. Nor are the Smokies covered in a “constant haze of these type of pollutants,” i.e., isoprene, as **Sam** clearly believes (isoprene, I repeat, is not a “pollutant.”) Rather, I argue, the “Smoky Mountains” got their name from the wisps of fog that often cloth their upper reaches in Spring, Fall, and Winter. And this fog, I claim, consists almost exclusively of water vapor. In the last round of this discussion, **Sam** provides the following information to back up his claims: > [@](#): > > \*\* The 14C content has now been measured in aerosol samples collected at TVA’s enhanced monitoring facility at Look Rock, Tennessee, on the western edge of the Great Smoky Mountains National Park. Results reported here are from samples collected during three seasons: spring of 2000, the summers of 2000 and 2001, and the fall of 2001. > > These measurements suggest that, at this southeastern rural location, the concentration of organic fine particles from “fossil” fuels remains relatively constant and low throughout all seasons—in the range of 1-2 micrograms per cubic meter (µg/m3). “Modern” carbon—largely originating from vegetation emissions and combustion of wood and agricultural wastes—varies from 2 to 6 µg/m3 and is highest in summer (Figure 1). Thus, “modern,” plant-derived carbon appears to make up 50 to 90 percent of the organic fraction of fine particles.\*\* …and then crows: > [@](#): > > - Get that? 50 to 90 percent of the ‘smog’ in the Smoky mountains comes from natural vegetation emissions. In the summer, the 90% number would be closer limit, and that explains why the ‘smog’ in the Smoky mountains is thickest in the summer. Specifically, terpenes emitted from the forests - the same stuff that gives Christmas trees their unique smell. \* …revealing, alas, once again, the fact that he simply doesn’t know what he’s talking about – or that, at the very least, he is anxious to frame the facts in way that gratuitously supports his agenda. The [**report**](http://www.tva.gov/environment/air/ontheair/fine_particles.htm) **Sam** cites is part of an ongoing project at the TVA, in conjunction with the EPA, to study the production and concentration of so-called “fine particles” in the atmosphere. As noted above, these are particles with a diameter of less that 2.5 micrometers, and are primarily comprised of sulfates and organic carbon. Unfortunately, **Sam** fails to understand (or chooses to ignore) that the project attempted to measure carbon particles exclusively, which in turn comprise only a portion of the total pool of fine particles found in the air. He therefore conveniently skips over the paragraph directly following his quote, which clearly states: > [@](#): > > \*\* Since organic fine particles (“fossil” and “modern”) make up, on average, about 30 percent of the total fine particle pool, the “modern,” vegetation-derived fine particles account for 10 to 25 percent of the total fine particle mass.\*\* Thus, his claim that “50 to 90 percent of the ‘smog’ in the Smoky mountains comes from natural vegetation emissions,” is a complete misconstrual – and a very long way from the 80% originally claimed by Reagan. In addition, we run into a definition problem here. The study makes no claims whatsoever about the abundance of NO, NO[sub]2[/sub], ozone, or PAN – the chemical components of what is traditionally understood as “smog” – at all. In fact, without the presence of man-made NO, isoprene cannot be converted into photosynthetic smog or produce ozone. So I am at a loss. Does **Sam** shift his definition of “smog” when convenient? Is it on occasion PAN/ozone, and on other occasions fine particle mass? Does a fine particle mass of 3 to 8 micrograms (a microgram is _1 millionth_ of a gram) of carbon per cubic meter of air constitute a “smog?” In fact, at least according to the [**EPA**](http://www.epa.gov/oar/oaqps/regusmog/infhaze.html), isoprene itself is not implicated in production of “haze,” which is the result of quantities of fine particles in the atmosphere (and is not the same thing as “smog,” by the way). The EPA has currently set a standard of 15 micrograms of PM2.5 per cubic meter air, a level which is proving difficult to meet for many areas of the Southeast, admittedly due to the combination of man-made and natural sources for these particles. Nevertheless, judging from the TVA report above, if we were to remove all human-generated sulfur and fossil-fuel sources of fine particles from the atmosphere, then the concentration of PM2.5 would fluctuate at a natural rate of between 2 and 6 micrograms per m[sup]3[/sup]. And of that quantity, an unknown amount is the result of “combustion of wood and agricultural wastes” – that is to say, is also man-made. In fact, the report speculates that the spike in “modern carbon” recorded during October 2001 was caused by “the burning of wood for heating, the burning of agricultural wastes, and forest fires.” Regarding the findings of this particular study, a [**related page**](http://www.tva.gov/environment/air/ontheair/part_composition.htm) summarizing the work done on the issue so far notes: > [@](#): > > \*\* As a rule, the fraction of sulfate is highest at rural sites, whereas _the organic carbon fraction is highest at urban sites_. > > This composition is consistent with earlier CMB modeling results which indicated that regional sulfate and particulate matter related to mobile sources (vehicles) and biomass combustion sources (high organic carbon content) accounted for most of the fine mass. Nitrates, soil dust, and other materials made only small contributions to total mass. > > …summer concentrations of organic carbon particles may also be higher, _but the evidence for this is less clear_. TVA data suggest that, in general, sulfate tends to be a larger fraction of fine particles in summer than in other seasons.\*\* The TVA air samples were gathered at Look Rock. If one were to visit Look Rock during the spring or summer (as I did many, many times in the days of my youth), you would be hard pressed to note any sort of “haze” or “blueness” among the branches. In fact, Look Rock is in the foothills, and seldom becomes particularly foggy at any time of the year – and especially not during the summer, despite the inordinately high levels of PM2.5. **Sam** : > [@](#): > > - I think that’s enough for now, since this is basically a hijack. Just doing my bit to fight ignorance.\* Sorry, but I fail to see how the willful misrepresentation of scientific findings falls into the category of “fighting ignorance.” ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [March 21, 2003, 3:06pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/2 "2003-03-21T15:06:18Z")
Although I’m eager to see **Sam Stone’s** response to this, I just want to pop in and say that this is one of the best OPs I’ve read on the SDMB. Informative, well-researched, and well-written. Thanks! Daniel ---
**Author:** ![Jammer](https://avatars.discourse-cdn.com/v4/letter/j/df705f/32.png) [@Jammer](https://boards.straightdope.com/u/Jammer)\ **Post date:** [March 21, 2003, 4:08pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/3 "2003-03-21T16:08:10Z")
I grew up not too far from the GSM. My grandfather and dad always said the mountains got the name from the frequent mists and foggy conditions that cause the valleys to look like they are full of smoke. I believe my grandfather. YMMV. 🙂 Jammer PS. It wasn’t smoggy in those mountains 35 years ago when I was a kid there. Those trees must be a lot more active now. We need to cut the bastards down before this pollution gets out of hand, I tell you!!! ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 21, 2003, 5:37pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/4 "2003-03-21T17:37:26Z")
Oh yes, great OP. You managed to smear my claim that the Smoky Mountains got their name from the blue haze from terpenes with the claims Reagan made. Then you made up a new name for me, **Conan the Canadian**. That’s very important to the debate. I thought personal insults were frowned upon around here? Or are cute little insulting nicknames de rigeur for the Straight Dope Board now? As for Trees and pollution, let’s start with [The Daily University Science News](http://unisci.com/stories/20021/0325024.htm): > [@](#): > > Nitrogen oxides from auto and smokestack emissions, among other sources, react readily with hydrocarbons to form compounds that eventually lead to ozone. **As former President Ronald Reagan asserted, trees are a big part of the problem – hydrocarbons from trees are just as effective as exhaust hydrocarbons in reacting with NOx to create ozone.** And here’s what the Berkeley Campus News says: > [@](#): > > Berkeley - Along the route from tailpipe through atmosphere, nitrogen oxides - collectively known as NOx compounds - react with hydrocarbons to form a variety of nitrogen-containing pollutants, including nitric acid, the cause of acid rain. Until now, however, **as much as half the resulting nitrogen oxide has been unaccounted for in the atmosphere, leaving air pollution models incomplete.** > > Chemists at the University of California, Berkeley, think they have found the missing nitrogen oxides with the aid of the most sensitive detector of nitrogen dioxide (NO2) in the world. > > Deploying the detector in downtown Houston and **in a remote Sierra Nevada forest, they detected large amounts of organic nitrogen oxide (NO) compounds, alkyl nitrates,** that were thought to be only a minor constituent of smog. In the forest, these alkyl nitrates included chemicals such as isoprene nitrate, which could only come from combining hydrocarbons emitted by trees with tailpipe emissions of NOx, presumably from the city of Sacramento, which is upwind of the forest. In Houston, other alkyl nitrates are formed by combining NOx with industrial hydrocarbon chemicals. From the [OGI School of Science and Engineering](http://www.ese.ogi.edu/newsarchive.html) > [@](#): > > The Wall Street Journal reported, in a cover story to the March 16, 1999 that Dr. Rasmussen is largely responsible for the often lambasted idea that trees are among the primary culprits behind smog. > > “We thought Reinhold was crazy initially,” says Joseph Bufalini, a retired Environmental Protection Agency air scientist. "Testing air gathered from plastic bags that he wrapped around tree branches, Dr. Rasmussen was electrified to discover that his **trees were pumping out huge amounts of isoprene, a natural hydrocarbon that is a key ingredient in the chemical interactions that create smog.** Previously, trees weren’t believed to emit significant amounts of iso-prene or any other hydrocarbons. Dr. Rasmussen, by the way, was the person Reagan was quoting in his ‘trees cause pollution’ comments. On to the Smoky Mountains… The [NOAA says this:](http://www.srrb.noaa.gov/UV/resources/airqual_PDF.pdf) > [@](#): > > Haze can also be the result of chemical reactions among various pollutants from automobile emissions. Car exhaust contains a variety of chemical compounds, including nitrogen oxides, carbon monoxide, and other compounds known as reactive hydrocarbons. These compounds arise from combustion and from unburnt fuel. Ultraviolet sunlight interacts with these gases to create a brownish haze layer called photochemical smog. **Ultraviolet radiation also reacts with terpenes and other hydrocarbons formed naturally by plants and trees. These reactions can contribute to the formation of smog.** From the [University of Regina:](http://www.eru.uregina.ca/kybettbd/chem103/Chem103%20SMOG.html) > [@](#): > > Plants emit hydrocarbons that can create smog; **the Blue Smoky Mountains of Virginia have smoke (smog) caused by hydrocarbons, mainly terpenes, emitted by the fir trees.** While we could not ban plants in cities, we could maybe restrict plants that emit a lot of terpenes. From: > [@](#): > > Isoprene is emitted from plants and trees and is widely present in the environment at low concentrations (Taalman 1996). **Isoprene global emissions, estimated at 175 to 503 million Mg per year, represent approximately 44 to 51% of total global natural volatile organic compound emissions** (Guenther et al. 1995). > … > The south central and southeastern areas of the United States have the highest biogenic emissions. **Summertime isoprene emissions are highest in each region and account for more than 50% of annual biogenic emissions** (Lamb et al. 1993). From this summary of the [Geology 299 course](http://www.sdsmt.edu/online-courses/geology/geol299/lect37.htm) at the South Dakota School of Mines and Technology: > [@](#): > > trees produce terpenes **which cause the haze of the Smoky Mountains** In the words of [Dr. John McKetta, Professor at Texas A&M, Chairman of the National Air Quality Management Commission and Chairman of the National Carbon Dioxide Greenhouse Commission:](http://www.lvrj.com/lvrj_home/1997/Mar-16-Sun-1997/opinion/5015398.html) > [@](#): > > "The trees and plants do not directly produce carbon monoxide. They exude other various chemicals including the terpene hydrocarbons. … **The Smoky Mountains received their names because of the cloud that was exuded from the trees in that area.** As these terpenes get into the air, they decompose into methane and other lighter hydrocarbons. These later oxidize to carbon monoxide while some are completely oxidized to carbon dioxide. This is well know to botanists and appears in all of the late botany books. From [This cite:](http://www-fhs.beth.k12.pa.us/kunkle/1921-1960.html) > [@](#): > > Great Smoky Mountain National Park near Gatlinburg in eastern Tennessee is the most visited park in the nation. Mr. and Mrs. Willis P. Davis started the park in 1923 and it was dedicated in 1940. It contains good examples of southern Appalachian upland deciduaous forest, high elevation coniferous forest, and in some coves, signs of former human occupation. The famous Appalachian Trail runs through the park. **The smoke of the Smokies was once caused by terpenes and other chemicals given off by the trees, but today, air pollution adds to the haze.** From this cite: > [@](#): > > As for the haze that is the origin of the name for the Great Smokies, is at least partially explained by Douglas M. Orr. Jr. and Alfred W. Stuart in their recently published “The North Carolina Atlas” from the University of North Carolina Press. They noted that, among other natural elements, **"some volatile organic compounds such as terpenes from pines and isoprenes from deciduous tree species help to produce the occasional smoky appearance of the Great Smokies and the bluish hues of the air over the Blue Ridge Mountains."** And let’s note that the Smoky Mountains got their name from Cherokee Indians in the 1700’s, long before there were any significant man-made contributions to pollution. So, to answer the OP’s question: Do the Smoky Mountains get their name from the pollution produced by all the trees? **YES** And I didn’t even have to insult you to make my point. What a concept. ---
**Author:** ![xenophon41](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xenophon41/32/253_2.png) [@xenophon41](https://boards.straightdope.com/u/xenophon41)\ **Post date:** [March 21, 2003, 5:51pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/5 "2003-03-21T17:51:17Z")
**Sam** , sorry to be blunt, but there’s no way a scientifically literate or even a moderately intelligent interpretation of the cites in your post and in the OP could support the impression that the answer to the titular question is “Yes”. The assertion, quite simply, is risible. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 21, 2003, 6:08pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/6 "2003-03-21T18:08:24Z")
Okay, where DID the Smoky Mountains get their name? The Cherokee Indians called it “A place of blue smoke”. I don’t recall the Cherokee Indians driving cars. Now, is ALL of the haze TODAY in the Smoky mountains due to terpene production? NO. Not even a majority of it, from what I can tell. That has nothing to do with HOW THEY GOT THEIR NAME. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 21, 2003, 6:10pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/7 "2003-03-21T18:10:34Z")
> [@](#): > > scientifically literate or even a moderately intelligent interpretation of the cites in your post and in the OP could support the impression that the answer to the titular question is “Yes”. So the University of Regina isn’t scientifically literate? Or the NOAA? Or the South Dakota School of Mines and Technology? Or Dr. McKenna? ---
**Author:** ![xenophon41](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xenophon41/32/253_2.png) [@xenophon41](https://boards.straightdope.com/u/xenophon41)\ **Post date:** [March 21, 2003, 9:18pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/8 "2003-03-21T21:18:59Z")
**Sam** , those citations don’t say what you say they say. You’re ignoring the context in which real air pollution occurs (emissions from industry combining with existing atmospheric chemistry) to exploit the widely acknowledged incidental contribution from the forest ecosystem. The Smokies are called that because of the blue haze that hovers over the mountains, caused by the amazing amount of water vapor released into the air by vegetation —more than one million gallons per square mile of spruce-fir forest per day. The area receives around [70 inches of rain](http://www.us-parks.com/US_National_Parks/great_smoky/great_smoky_climate.shtml) per average year, courtesy of warm, moist air from the Gulf of Mexico shedding its moisture as it rises over the mountains. On spring and summer days, the same solar energy which reacts with those terpenes you and Ronnie are so worried about also prompts the vegetation to release moisture; that’s where the million gallons per sq. mile comes from, and that goes straight up until it hits the heavy, moist air that’s already there, and voila… smoky mountains. It’s a light, clear bluish haze that looks quite a bit like wispy smoke. Indeed, it kept the Cherokee from being able to use smoke signals for long distance communication on most days. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 21, 2003, 9:36pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/9 "2003-03-21T21:36:48Z")
I’m baffled. You say they don’t say what I say they say. Or something. Yet, the quotes are very specific. I don’t know why I have to repeat them, but… University of Regina: \*\*the Blue Smoky Mountains of Virginia have smoke (smog) caused by hydrocarbons, mainly terpenes, emitted by the fir trees. \*\* Dr. J.J. McKetta: \*\*The Smoky Mountains received their names because of the cloud that was exuded from the trees in that area. \*\* South Dakota School of Mines and Engineering: **trees produce terpenes which cause the haze of the Smoky Mountains** The NOAA: **Ultraviolet radiation also reacts with terpenes and other hydrocarbons formed naturally by plants and trees. These reactions can contribute to the formation of smog.** Here’s another cite: [North Carolina Division of Air Quality:](http://www.smartcommute.org/OzInfo.htm) > [@](#): > > Over the years, visibility in the Smokey Mountains has been reduced from 93 miles to 22 miles. The Smoky Mountains did not get their name from this man-made pollutant haze. Rather, the name comes from the blue color of the mountains when seen from afar. Naturally occurring VOCs (volatile organic compounds i.e. terpenes - SS) from the trees give the air a bluish cast without reducing visibility. Now, I don’t see a lot of opportunity for misinterpretation here. Is the message coded? Is there a ‘just kidding’ hidden in there if you arrange the letters just right? ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [March 21, 2003, 9:57pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/10 "2003-03-21T21:57:25Z")
I think the problem may be that, while trees do produce some particulates that change the appearance of the air, and while this change may be responsible for the Smoky Mountains’ name, it’s disingenuous to call those particulates pollution. Furthermore, generally this argument is brought up as a canard, suggesting that the particulates formed by trees are responsible for the haze we see here in Asheville and other Appalachian communities. I think that Sam might be right on the purely technical matter: if you consider the tree particulates and water vapor to be “pollution,” then sure. But the larger issue, of whether trees are responsible in any meaningful sense for pollution, is far different. Daniel ---
**Author:** ![xenophon41](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xenophon41/32/253_2.png) [@xenophon41](https://boards.straightdope.com/u/xenophon41)\ **Post date:** [March 21, 2003, 10:03pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/11 "2003-03-21T22:03:19Z")
**Sam** , I’m kinda baffled here. You’re clearly (from the context of your posting history) _not_ an idiot. However, you’re also not known to deliberately misrepresent factual data. Yet, here we are where you’ve yet to produce a cite for pollution coming from trees in the Great Smoky Mountains, nor a cite which credits naturally released hydrocarbons with any appreciable production of smog through photochemical reactions… and you’re claiming the cites support the assertion that “the Smoky Mountains get their name from the pollution produced by all the trees.” Odd. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 21, 2003, 10:29pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/12 "2003-03-21T22:29:01Z")
So that’s the nitpick? The word ‘pollution’? The clear fact is, the Smoky Mountains got their name because terpene emissions caused a bluish haze. Terpene emissions can be categorized as ‘pollution’. That was the question in the OP to which I answered. Every cite I posted agrees with that, and they are all from academic or scientific organizations. This has nothing to do with the other question, which is how much do terpene emissions contribute to pollution in the Smoky Mountains TODAY. And Mr. Svinlesha has a good point about that, which I overlooked - instead of being 50-90% of the total, it may in fact be more like 10-25%. But that’s not the question the OP asked. He asked about the ORIGIN of the name. I posted many cites giving the answer to that question. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [March 22, 2003, 12:08am UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/13 "2003-03-22T00:08:52Z")
Unless you know a real old Cherokee you don’t know if the blue tint caused the name or just the haze, and the haze is mostly water. To call naturally occurring turpenes a “pollutant” is more than a stretch. Do they, in the form released by trees, cause a health or environmental risk? No? They are part of the needed environmental carbon cycle? Oh. Trees bind more carbon than they release and are the great carbon sink. No health risk? Nope. Plant derived turpenes are used to flavor toothpastes and mouthwashes. Not a nitpick, the crux of the statement. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [March 22, 2003, 1:53am UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/14 "2003-03-22T01:53:48Z")
Just because something makes a nice flavor for mouthwash doesn’t mean I want to breathe it. ---
**Author:** ![xenophon41](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xenophon41/32/253_2.png) [@xenophon41](https://boards.straightdope.com/u/xenophon41)\ **Post date:** [March 22, 2003, 1:58am UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/15 "2003-03-22T01:58:38Z")
**DSeid** has it exactly right. But you knew that, **Sam**. You and Ronnie used the word “pollution” because that bogus 50 - 90% figure for “pollution caused by trees” --:rolleyes:-- is used purely to support the political idea that automobile and industrial emissions limits need not be set “too low”. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [March 22, 2003, 4:08am UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/16 "2003-03-22T04:08:51Z")
Actually, natual terpene emissions CAN be a health risk. I think it’s you that is drawing an artificial line. You are defining ‘pollutant’ as ‘man-made’. I don’t draw that distinction… Once a pollutant is in the air, it doesn’t matter if it came out of a tailpipe or an oak. Some of the links I pointed to actually discuss health risks from urban vegetation due to various natural emissions. The conclusion in one of the links was that on balance the urban vegetation was a good thing, because other positive environmental factors outweigh the _pollutants_ they emit. From [this cite,](http://www.pcimag.com/CDA/ArticleInformation/features/BNP __Features__ Item/0,1846,25107,00.html) > [@](#): > > **Ironically, many parts of the country will automatically wind up in violation of the EPA’s proposed levels, due to naturally occurring VOCs (isoprene and terpenes) that are emitted by vegetation.** In some parts, these emissions are heavy enough to account for natural smogs that will not go away with the demise of the petroleum industry. **Ever hear of the Smoky Mountains? Well, they aren’t that way from Grandpa’s old wood-burning stove! That haze, common to many forested mountain regions, was there long before many of our ancestors arrived. Environmental scientists explain that, “The terpenes are the primary source of the blue atmospheric haze of forested areas which forms when terpenes are activated photochemically and agglomerated into aerosol particles as large as 2 microns in diameter** …[Environmental Scientist] F.W. Went estimated that coniferous forests produce at least 5 tons of volatile organic matter per km2 per year.”1 > > Scientists have estimated that global terpene emissions could be 10 times as high as man’s total annual non-methane hydrocarbon emissions. Nevertheless, the architectural and industrial paint sector, which emits less than 2% of potentially reactive VOCs, was recently trounced by a national architectural industrial maintenance (AIM) rule that will directly result in the loss of savings, product quality and will significantly increase the amount of paint waste materials generated at construction sites. Many of the VOCs traditionally used in coatings are only marginally reactive, and then only under conditions optimal for ozone formation. Air chemistry in general — and the smog phenomenon in particular — is far too complex to simplistically address with a one-size-fits-all VOC regulation, such as the national AIM rule. Nevertheless, the latest NAAQS for ozone, if enforced as it exists, will eventually force states to consider the ban of any paint that would even approach the relatively “lenient” levels allowed under AIM. Note that this cite is the first non-academic or government source I’ve posted, so take it for whatever veracity level you want. [Here’s a cite](http://www.uaf.edu/coop-ext/forestry/canopy/canopyjun98.html) which details a grant request to study the effect of natural terpene emissions on groundwater in Alaska. > [@](#): > > Spruce defensive mechanisms involve the production of large quantities of pitch or resin which contain high concentrations of defensive compounds such as terpenes. A small percentage of overstory trees are surviving within effected areas. The contributions these surviving trees will make to the genetic composition of the future spruce forests of the area could be significant. It will be important to determine if the defensive compounds produced by these live overstory trees are different or more concentrated than those produced by the dead overstory trees. > > A pre-bark beetle attack research project in Resurrection Bay in 1989 reported finding low concentrations on terpenes in seawater. The effects of a large region of spruce forest producing copious quantities of spruce resin concentrated with terpenes leads to the concern that concentrations of terpenes and related metabolic compounds may be being concentrated in nearby fresh and salt water systems. Preliminary indications of toxicity of related metabolic compounds from terpenoids suggest necessary investigation of their effects on salmonids. From[This cite:](http://www.arb.ca.gov/research/ecosys/biogenic/dec2000/BiogResPlan.pdf) > [@](#): > > Even in the highly urban South Coast Air Basin (SoCAB), the biogenic ozone forming hydrocarbon emissions are an increasing fraction of total hydrocarbon emissions (~15%-20%). Biogenic hydrocarbons can also form constituents of Particulate Matter 2.5 micrometer in diameter and less (PM2.5). > … > Photochemical modelers have found biogenic emissions from the > agricultural and urban vegetation have the highest impact of all biogenic emissions on ambient ozone concentrations. Urban vegetation that is routinely irrigated can have a disproportionate effect on ozone levels. From [this report at the EPA:](http://www.epa.gov/chemrtk/aroterhc/c13972tp.pdf) > [@](#): > > Based on the above estimates,it can be concluded that total annual atmospheric emission of p cymene is predominantly from biogenic sources (17,200,000 kg/yr of biogenic emissions versus 400 kg/yr of anthropogenic emissions).The relative contribution from biogenic and industrial sources can be represented by a global emission ratio (GER =biogenic emission/industrial emission).In the case of p -cymene,the GER would exceed 1,000,suggesting that biogenic emissions far exceed man-made emissions. Here’s what the [New Hampshire Department of Environmental Services](http://www.des.state.nh.us/factsheets/ard/ard-21.htm) has to say: > [@](#): > > **In New Hampshire, certain portions of the state exceed the federal health standards for ground-level ozone, the major component of "smog.** Ground-level ozone is formed when volatile organic compounds (VOCs) combine with oxides of nitrogen in the presence of sunlight and heat. Examples of VOC-containing materials include coatings, industrial and commercial solvents, petroleum products (e.g., gasoline), diluents, thinners, degreasing agents, and propellants such as isoprene and terpene. **In New Hampshire, VOC emissions result primarily from natural (biogenic) sources**, with some contribution from human (anthropogenic) sources. **Biogenic VOCs originate mainly from forests and urban/suburban vegetation.** Anthropogenic sources include transportation (cars, trucks and gasoline loading/unloading), industrial processes (especially coating, finishing, printing and graphics arts, and metal degreasing), and commercial and household use of solvents and architectural coatings (e.g., paints and stains). Note: I’m not drawing any conclusions here about the overall health effects of biogenic emissions of pollutants and man-made emissions. I just want to establish the following facts: 1. Trees emit terpenes, a chemical which is considered a pollutant. 2. Some forests, such as those in the Smoky Mountains, emit enough of it to cause a bluish haze. 3. This haze is responsible for the name ‘Smoky Mountains’. Thus answering the op: **YES** ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [March 22, 2003, 4:57am UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/17 "2003-03-22T04:57:35Z")
While I maintain my belief that natural terpene is different than anthrogenic terpene (my understanding is that it is more rapidly degraded) I do cede to the information presented that natural terpenes can contribute to ground level ozone and smog, which have deleterious health effects, so therefore count as pollution. Now as to that old Cherokee … ---
**Author:** ![woolly](https://avatars.discourse-cdn.com/v4/letter/w/ebca7d/32.png) [@woolly](https://boards.straightdope.com/u/woolly)\ **Post date:** [March 22, 2003, 12:22pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/18 "2003-03-22T12:22:37Z")
To the west of Sydney is a area known as the [Blue Moutains](http://www.worldsurface.com/browse/location.asp?locationid=4273) . The source of the distinctive blue haze is the vaporation from the native trees of [eucalyptus oil](http://www.oilmallee.com.au/docs/BARTON.doc) “Industrial Uses of Eucalyptus Oil” > [@](#): > A few Eucalyptus species, mainly mallees, produce a leaf oil for which there is an existing limited world trade as a pharmaceutical product and a large potential market as an industrial solvent… Eucalyptus oil based products have been used as a traditional non-ingestive treatment for coughs and colds (Opdyke, 1975), a topically applied medication for relief of muscular pain (Hong and Shellock, 1991), and as a solvent/sealer in root canal dentistry (Leung, 1980)… It has uses as a fragrance in soaps, detergents and perfumes and as a flavouring in food (Furia and Bellanca, 197 1). Household uses include spot and stain remover and a wool wash component. It has also been used as a flotation agent in the mining industry (Clarke and Moore, 1931) ] [/QUOTE] Whether it would be valid to categorise something as ubiqitious as eucalyptus in Australia as a pollutant is not a question I’m qualified to answer, but my guess is no. ---
**Author:** ![Mr.Svinlesha](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@Mr.Svinlesha](https://boards.straightdope.com/u/Mr.Svinlesha)\ **Post date:** [March 22, 2003, 12:25pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/19 "2003-03-22T12:25:26Z")
**Daniel** : Thanks! Just doing my bit to fight ignorance, you know. Ahem. 🆒 **Jammer** : Yea, verily, your grandfather sounds like a wise and learnéd man. **Sam** : > [@](#): > > _Oh yes, great OP. You managed to smear my claim that the Smoky Mountains got their name from the blue haze from terpenes with the claims Reagan made._ _I_ did? You were the one who originally brought them up in conjunction, back in that previous thread. I understood that you felt they were connected by the fact that the amount of isoprene produced by the biomass supported Reagan’s claims that 80% of the world’s pollution comes from “plants and trees.” May I ask, since you have not publicly recanted, if you still believe Reagan’s statement to be accurate? > [@](#): > > - Then you made up a new name for me, **Conan the Canadian.** \* No I didn’t. That particular moniker has been floating around for a couple of days now, thanks (I believe) to your friendly neighborhood **elucidator**. Clearly, you’ve not been keeping abreast of current SDMB developments. > [@](#): > > - That’s very important to the debate. I thought personal insults were frowned upon around here? Or are cute little insulting nicknames de rigeur for the Straight Dope Board now?\* See, this is what I don’t get. You seem to feel that you are within your full rights to insult other posters (like **Elvis** , in [**this thread**](http://boards.straightdope.com/sdmb/showthread.php?threadid=170882&pagenumber=1)), or to post hateful tripe such as the following: > [@](#): > > - Well, the peace protests are ORGANIZED by loonies. The Worker’s World Party? Stalinists in the 21st Century? Various Communist organizations? Hoo boy. You want to attract flies, start with a big pile of dung.\* …also a typical example of the misleading overgeneralizations you seem so fond of. And yet _you_ feel insulted when paid back in kind? Well, gee, **Sammy** , awfully sorry to hurt your feelings, but if you can’t stand the heat, get out of the kitchen. On the other hand, if you wish to be treated with respect, you might start by showing a little respect even towards those with whom you disagree. With regard to your “Trees and Pollution” section, nothing you’ve cited from the DUSN, Berkley Campus News, or OGI contradicts the points I made in my OP – in fact, I used those sources myself in preparing it! To reiterate (since you didn’t directly address my response), isoprene itself is not a “pollutant,” as the term is commonly understood. Anthropogenic sources of NO must be available in order for the chemical reactions that produce ozone and smog to take place. If I’ve understood correctly, the chemical process proceeds in this manner: isoprene + nitrous oxide = alkyl nitrate (a so-called “NOx,” in this case more specifically, isoprene nitrate); alkyl nitrate + ultraviolet radiation = ozone, nitrous dioxide, and peroxyacetylnitrate (i.e., “photochemical smog”) Large amounts of NO are produced in urban areas in the form of exhaust from cars, various industries, and two-stroke lawnmower motors. The NOx (isoprene nitrate) detected by the Berkley team could only form because man-made pollutants were present as well. You’ll note that the team made no claim for having discovered “smog” in the Sierra Nevada forest, only unexpectedly high concentrations of NOx, and explained this finding by the fact that they were downwind of a major urban center (Sacramento). But the point here remains that the specific statements made by Reagan, such as “Trees cause more pollution than automobiles do,” are massive oversimplifications, extremely disingenuous and misleading. Reagan simply prefers not to mention the fact that taken in isolation, 80% of the isoprene produced by trees rapidly breaks down into CO[sub]2[/sub], and that the remaining 20% reacts with sunlight to release micro-particles of carbon, which in turn function as condensation nuclei. As the TVA measurements indicate (not to over-generalize, mind you, but just as an example), the total quantity of these particles in the Smokies fluctuates somewhere between 2 and 6 micrograms/m[sup]3[/sup] of air, well below the EPA standard of 15 mg/m[sup]3[/sup] and an unknown amount of that total is _also_ man-made. By the way, without condensation nuclei, clouds would not form, and there would be no rain. In addition, the earth’s albedo would be significantly reduced, making our homeworld a much hotter place. Thus, the particles produced by isoprene emissions perform an absolutely vital function in the earth’s ecology, and I submit that the existence of a certain amount of fine particles in the atmosphere is absolutely necessary for our planet’s well-being and cannot therefore be reasonably classified as pollution. YMMV. By promoting these claims, you seem intent as well on willfully misrepresenting these findings and perpetuating, rather than fighting, ignorance. You’ve stated, for example, that Reagan was “absolutely right,” even though he patently was not. You have yet to admit that this statement was less that correct. You’ve stated that trees emit “hydrocarbons and ozone,” when in fact they do not emit ozone. By twisting or flatly misrepresenting scientific findings, and combining fact with fiction, you present alarmist and misleading half-truths to support your political agenda. It appears that you don’t even fully understand the material you cite to support your case, as I pointed out to you regarding your interpretation of the TVA study. > [@](#): > > - Dr. Rasmussen, by the way, was the person Reagan was quoting in his ‘trees cause pollution’ comments.\* Do you have any evidence for this claim, or are you simply assuming it to be so? I’m running out of time IRL, now, but must briefly comment on your cites regarding the Smokies. The question here is, “Did the Smoky Mountains get their name from the pollution caused by all the trees?” which is what you have claimed, above. I’m going to get a little stiff-necked now, if you don’t mind. Your first NOAA cite simply reiterates the points I’ve made above, and is irrelevant to the question. You’ve quoted the passage from the University of Regina before; I avoided it because it contains no evidential backing, and is mentioned in an offhand and anecdotal manner in the body of the paper. Anyway, we may be at cross purposes here; originally, you referred to the “Smoky Mountains,” a stretch of the Appalachians that runs through Tennessee and North Carolina; this cite refers to the “Blue Smoky Mountains” of Virginia. I must admit I’ve never heard of the Blue Smokies before, so I’ll have to get back to you on it. Finally, the passage makes no reference whatsoever to the manner in which the Smokies got their name. Your third cite, source unknown, is also irrelevant to the topic at hand, as far as I can tell. Your fourth cite, a geology lecture, states (again without any evidential backing), that terpenes “cause the haze of the Smoky Mountains.” Again, as pointed out earlier, “haze” is the result of fine particles in the atmosphere, _some_ of which are produced isoprene reacts with sunlight. In a roundabout way, then, this seems correct; and I am willing to concede that the condensation nuclei produced by the reaction of isoprene to sunlight leads to a higher level of water condensation in the atmosphere (i.e., fog) than one might find in an environment without such particles. The cite makes no mention whatsoever of how the Smoky Mountains got their name. Your fifth cite, taken from a opinion piece, was written by Edmund Contoski in defense of some statistics he employed in his book, “_Makers and Takers_,” dedicated to showing “ how the free market works–and why government intervention doesn’t.” In it, he claimed that “ 93 percent of atmospheric CO is produced by nature and that this poisonous gas is produced by trees and other foliage.” Clearly, a reliable source, but I’ll stick with **Jammer’s** grandfather, if you don’t mind. Dr. McKenna provides no evidence to support his claim either, and this cite is little more than an appeal to authority. I must round off now. Before I do though, I want to react to two other statements you’ve made: > [@](#): > > _So that’s the nitpick? The word ‘pollution’?_ Hardly a nitpick, as has been pointed out, quite well I think, by **Daniel**. Rather, a canard, which is why I started this thread in the first place. Did you not notice the title? > [@](#): > > - This has nothing to do with the other question, which is how much do terpene emissions contribute to pollution in the Smoky Mountains TODAY. And Mr. Svinlesha has a good point about that, which I overlooked - instead of being 50-90% of the total, it may in fact be more like 10-25%.\* Wrong again, **Sam**. Terpene emissions contribute to 10 – 25% of the total amount of _fine particles in the atmosphere_, which is in turn only a fraction of the total pollution in the Smokies. There are scads of other sources of pollution – such as particle mass above the PM2.5 range, acid rain, and so on. And to repeat once again, a certain amount of micro-particles are necessary for the formation of clouds and so forth, and therefore cannot rightly be classified as pollution. I’ll try to get back to the rest of this later in the evening, provided that **Mrs. Svinlesha** doesn’t bite my head off for wasting so much time here. **DSeid** : Nice to see you again. 🙂 In a previous thread, you had inquired about my son. Did you get my reply? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [March 22, 2003, 5:59pm UTC](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091/20 "2003-03-22T17:59:19Z")
Just so I can keep track of the argument at this point it appears the main issues at odds in this discussion are - 1: How is term “pollution” characterized in considering the origin and components of a specific, localized atmospheric haze? Can naturally occurring atmospheric products of a segment of the carbon cycle (terpenes etc) be characterized as “pollution” in this haze? 2: Are some of these suspended atmospheric products of the carbon cycle in this haze (terpenes etc) critical to the observed nature of this haze being considered as a “smokey haze” and thus to the naming of the area or are these products not really relevant to the “smokiness” aspect regarding the origin of the name “Smokey Mountains”. The first issue seems (to me) to be more of a semantic debate over the conceptual nature of what is and is not “pollution” than a strictly scientific debate as to the nature of the complex interplay of various hydrocarbons and other natural and man made substances in the atmosphere. The second issue as to the terpenes etc. giving the the haze a unique “smokiness” (vs other hazes) and thus being responsible for the name “Smokey Mountains”, is largely unknowable at this point unless we have both a time machine and a way to test how removing these atmospheric components (in the past) would have affected the way they looked. [Next page](https://boards.straightdope.com/t/do-the-smoky-mountains-get-their-name-from-the-pollution-produced-by-all-the-trees/163091.md?page=2)