Domestic chemical warfare

A reader writes:

My brilliant son put a jar of mustard in the microwave for... a while. When we regained the ability to breathe and I managed to stop laughing, I grounded him because of his clear violation of the Chemical Weapons Convention, to which Australia is a signatory.

Then I started thinking. We just inhaled gaseous hot English mustard... does that mean we just inhaled mustard gas? Are we now at a higher risk of lung cancer, or something?

Caitlin

"Mustard", in culinary parlance, is a condiment made from mustard-plant seeds. Hot mustard is bad news if you get it in your eyes or sinuses, on account of a compound called allyl isothiocyanate, or AITC to its friends.

"Mustard", in chemical-weapons parlance, refers to any agent which creates a burning sensation and "lachrymatory" effect similar to that of AITC, and generally also has a somewhat similar smell to culinary mustard. These compounds are not at all related to edible mustard, though, and all have exciting extra toxic effects. The original "sulfur mustard" compounds that were used in World War I, for instance, are highly carcinogenic and cause agonising skin blisters and chemical burns, which can take as much as a day to develop.

It would be unwise of me to mention, in these pages which your son may read, that microwaving pepper can create a similar noxious cloud, the active agent in which is "piperine".

So I will not.


Psycho Science, as I have brilliantly decided to call it, is a new regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

The flash from a hydrogen bomb works pretty well

A reader writes:

Why can't you see the bones in your finger/hand when you shine a bright light through it? Veins show up well, but bones are practically invisible. Are live bones as see-through as live flesh?

Ryan

Bones, alive or dead, are pretty much opaque to visible light. If your flesh were for some reason perfectly transparent but your bones stayed as they are, you'd be a lovely Ray Harryhausen walking skeleton. (Or, more accurately, a Fritz Leiber ghoul.)

Your flesh isn't transparent, though; it's translucent, and diffuses light that enters it. So instead of your hand-bones being as visible as a fish in an aquarium, they're as invisible as a fish that is for some reason attempting to survive in a tank full of milk.

If that fish in its milk-tank comes close to the side of the tank, you'll be able to see it, just as you can see the little dark veins that're close to the surface on the palm side of your fingers when you shine a flashlight through your hand. Just the few millimetres of flesh on either side of the bones, though, diffuses the light so much that it's hard to tell that there's a bone there at all.


Psycho Science, as I have brilliantly decided to call it, is a new regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

Waiter! This Marlboro is corked!

A reader writes:

Most cigarettes have a wrapping around the filter that looks like cork, because apparently the earliest filter cigs had a filter made of cork.

How the hell did that work, though?

Isn't cork used for, well, corks, because it's impermeable? How could you suck smoke through a cork? Perhaps smokers in 1940 were more health-conscious than we thought, and enjoyed these Unsmokable Health Cigarettes!

Luca

Today, most cigarette filters are made of cellulose acetate fibre, a substance of many uses (from cloth for garments to stuffing cushions) which is made by reacting plant cellulose with acetic acid.

But cigarette filters are, as you say, usually covered with a layer of paper printed with a cork pattern. And yes, that's because in the olden days the filters were made of cork. (This makes the printed-paper filter a "skeuomorph", an object with cosmetic design elements held over from an older version of the same thing.)

Cigarette filters were, however, never solid cork; as you say, that would be ridiculous. Instead, the filter was actually filled with loosely-packed cork granules, or a loosely-rolled piece of paper, which might itself have been made from cork.

There's nothing about cork that makes it a particularly excellent filter material. It was just a relatively cheap substance that wouldn't do anything very alarming if the smoker smoked all of the tobacco and sucked the flame back into the filter.

Cigarette filters have the peculiar task of blocking some bad stuff from getting into the smoker's lungs, without blocking the bad stuff that the smoker's paying to put into their lungs. (See also guns, which are generally designed to be simultaneously as safe, and as dangerous, as possible.)

So a really good filter material, like activated carbon, would be no use in a cigarette. Instead, filter materials with relatively low surface area are used. Activated carbon works so well as a purifying filter because it's immensely porous, giving it an enormous surface area per gram and allowing it to "adsorb" a surprising amount of stuff. Cellulose acetate fibres, of a similar consistency to cotton wool, adsorb rather more "tar" than the old cork filters, while letting various other compounds through.

Both cigarette filters and long cigarette holders do catch some particulate matter and "tar", but their actual effect on smokers' health is difficult to detect.

(See also "light" cigarettes that have air holes in the paper around the filter to dilute the smoke. In theory, they could actually be somewhat healthier than regular cigarettes, but in reality, there's no good evidence that "light" cigarettes are any better. Smokers cover the holes with their fingers, or just smoke more, or more deeply; however it happens, health outcomes are the same no matter what mainstream-Western-market cigarette you smoke.)


Psycho Science, as I have brilliantly decided to call it, is a new regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

Mystery crystals

A reader writes:

I was walking down the street at three in the morning after a night out, in the middle of winter [here in Australia], and there was twinkling frost all over the top of a parked car. And the next parked car. But not the one after that.

I kept looking, and the difference was that cars that were parked under a tree had no frost, but cars that were in the open were frosty.

The air temperature was pretty low, but it wasn't below freezing - I checked later and the local weather station said it got down to about 4 degrees C.

Did frost fall down out of the sky and somehow... stay?

Finn

It was a clear night with no breeze, right?

On a clear night, the sky above you is a window to deep space. There's no sun keeping things warm, no diffuse sky radiation making the sky blue and at least a bit warm wherever you look; just a blanket of air, and then space.

Heat can pass by convection, conduction and radiation. Radiation, for most items humans encounter, is the least important of these three paths. But if an object has a wide view of something which, like deep space, is close to absolute zero, then it can radiate enough heat to drop below zero Celsius, even if the ambient air temperature is a little above freezing.

If there's even a light breeze, the passing above-freezing air will keep surfaces too warm for frost to form, by allowing heat to move by convection - in this case forced convection (as in the case of a computer CPU's heat sink cooled by a fan). Likewise if a surface is directly connected to something with a large heat capacity, allowing that surface to stay warm by conduction (as in the case of the CPU itself, in physical contact with its heat sink). The thin steel roof of a car will form frost in these conditions; a solid block of steel would not, because radiation wouldn't be able to cool all of it enough before the sun came back up.

The less of a direct view a surface has of the sky, the smaller this already-small effect will be. So cars - or rubbish bins, or other thermally-isolated surfaces - that're in the "shade" of a tree or building probably won't frost up. (There could be some interesting odd cases, if for example a car is parked next to a skysraper covered with IR-reflective glass.)

This same phenomenon can be used to make ice in a desert, if that desert has clear, still nights. Wide shallow trays of water held up off the sand by narrow supports can freeze surprisingly quickly.


Psycho Science, as I have brilliantly decided to call it, is a new regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

H-two-whatever

A reader writes:

I was wondering if you have come across "Water Ion Technologies" before. My skills tend towards electronics or I.T., and about the most interesting thing I ever did with chemicals probably wasn't that good for me at the time. I know you're not really a chemical science site, although, in fairness, you seem to derive some small amounts of schadenfreude from debunking some of the more obvious pseudoscience shysters that inhabit the 'net. God knows I do when you do it.

So... Should I be super excited about what they're saying, or do I need to take more of those chemicals before their vision will fit into my reality?

Richard

Usually, purveyors of magic water at least somewhat restrict their claims.

Usually, it's good for what ails you. Either it's treated with magnets or dual overhead quantum recipulating sprines, or it's just some mildly alkaline spring water that the seller declares to be Water Of Gladness or whatever. And away they go selling the stuff, come what may.

Or perhaps it's not of medical value, but you can run your car on it.

Or it's not water at all, but separated hydrogen and oxygen that for ill-described reasons has properties far more useful than the hydrogen and oxygen dealt with by boring old scientists.

Water Ion Technologies seem to have opted for "all of the above".

Their main discovery, you see, is a mystic substance called "SG Gas", which is not H2O but "O-HH", and has a long list of properties that'll pretty much overturn the entirety of molecular chemistry if they turn out to be real.

(The Water Ion Technologies "science" page also, according to ancient psychoceramic tradition, rambles on about the patents they've applied for, as if having a patent on something means that the thing works.)

But wait! If you "infuse" water with SG Gas, you get "Ultra-Pure Polarized Water", also known as the "AquaNew" product Aqua Cura "Watt-Ahh", which combines at least five forms of pseudoscience to provide 100% of your daily requirements of whatever the hell it is they're talking about.

(Actual scientists may find the Watt-Ahh "Studies" page particularly entertaining. Watt-Ahh doesn't have anything but water in it, oxyhydrogen doesn't kill cells, capacitance testing somehow proves they're really making "clustered water", now suddenly their nothing-but-water product is supposed to kill germs although that's not actually what they did with it to reach this conclusion, and now, surprise, it's a treatment for autism! And good for cut flowers. And on it goes.)

If this were the first miracle hydrogen-oxygen gas, or the first miracle water, promoted with a well-tossed salad of quantum flapdoodle, crackpot physics and claims about "hydration", "cellular communication", "detoxification", and so on, then I might be inclined to give them slightly longer shrift. Heck, they've even got one study done by a real scientist at a real university... using their own odd in-vitro protocol. But c'mon, it beats the heck out of the tests in which they forget to tell you the results.

The thing is, though, that mysterious hydrogen-oxygen gases are a long-term crank favourite. Often described as "HHO" or "Brown's Gas", they're forever allowing people to get a thousand miles per gallon or burn the gas to get back more energy than they used making it, except when some tiresome empiricist shows up and tries to actually test these claims.

And as for magic water, well, your one-stop shop for an overview of the surprisingly large number of magic-water products out there is "H2O dot con". Their page about water cluster quackery goes into claims like the "Watt-Ahh" ones in some detail; Watt-Ahh has its own little entry on the depressingly long list of similar products and devices.

Could this stuff be real? Sure, insofar as the claims made for it are even physically possible.

Since this is another potentially world-changing product that's mysteriously being sold piecemeal to individual consumers rather than turning into a multi-billion-dollar business, though, I see no reason to give it any more credence than any of the many, many, many other products in the same market sector.

Oh, all right. One more fuel additive.

A reader writes:

I've read all your various fuel-additive debunking pieces, and while I'm assuming that this is Just One More Of The Same, I would like your opinion:

http://www.ecofuelsaver.com/

Big, flashy web page. Graphics and embedded videos. And not only testimonials, but actual Lab Results!!!

The How It Works web page sounds awfully dodgy to me, though, and the FAQ page makes me even more skeptical. On the other hand, they go to great lengths to differentiate themselves from being just another engine cleaner, and give myriad details about how to properly do testing so you can see the results for yourself. Also, the information given in their "EPA & CARB certified Lab Results" page is big on scientific rigor, discussing the need for consistent baseline runs and blind testing so the driving habits do not affect the outcome. (Of course, it could all be made-up hooey, but that's the chance we take.)

Point is, they sound good. And the product is being sold by Canadian Tire, a very large Canadian retail outlet.

(Canadian Tire is an institution in Canada. They are a Wal-Mart like store, but have been around for some 90 years. For 50 years have a 'store loyalty' program called Canadian Tire money, where some small percentage of your purchase is refunded to you in Canadian Tire Money. This 'money' is of *very* high quality; it is, in fact, better (better paper and ink, stronger security measures) than the national currency of some countries I have travelled. It is gladly accepted by charities, frequently given in larger denominations as wedding gifts, and is often used as a sort of alternate currency, trading at par among friends or even friendly strangers. Thus endeth the lesson.)

Anyway, since Canadian Tire is endorsing the stuff, I expect that many folks are going to be trying it. I know you have seen many scams of this nature, so I beseech you to train your skeptical and knowledgeable eyes on this potential snake-oil from the Great White North.

Shane

Yeah, here we go again.

This outfit does indeed have a better spiel than most fuel-additive sellers, but there on their How It Works page is the usual claptrap about raising octane rating.

Raising a fuel's octane rating above what an engine's compression ratio and ignition timing requires will, for an absolute certainty, do nothing at all, and certainly not improve an "incomplete burn", a concept which the Eco Fuel Saver people also share with dozens, if not hundreds, of other fuel-additive companies.

Modern engines all burn very very nearly all of the fuel, or else they fail emission testing and/or set the catalytic converter on fire.

And on it goes, blah blah blah, and then there are those nifty PDF test datasheets you mentioned - which are, once again, of a quality well above the norm for these outfits, and not even from California Environmental Engineering!

This post has been sitting on my to-do pile for rather a while; when I first replied to Shane I observed that the "Gasoline" test-results document said that the tests were done in 2006. And here we were, years later, and this hundred-billion-dollar product was still being sold over the counter to individual motorists. On account, perhaps, of a Conspiracy.

Now they've got documents from 2011 on the lab-results page, though, and all they say is that their additive doesn't ruin the fuel, and in fact changes it in almost no way at all. Then, puzzled, you might try their "Results" page instead, but all you'll find there is a list of variably plausible excuses for the additive doing nothing noticeable. But don't be fooled - Eco Fuel Saver will "increase BTU, octane and lubricity in your fuel", so never mind our own PDF test results that proudly indicate an octane change, for instance, of less than half of one per cent, and the fact that even a large octane increase makes no difference unless your current fuel is causing knock or making your fancy computer-controlled engine retard its spark; just clap your hands, children, and wait for Tinkerbell.

I could dig further into this, but it's like investigating every new prophecy of the end of the world or dude who reckons he's channelling a million-year-old alien, yet is mysteriously unable to even tell you pi to ten significant digits, let alone anything of scientific interest that millions of human high-schoolers don't already know.

It's up to the makers of all of these products to demonstrate the value of their incredibly valuable, if true, claims. It's not up to us to sort through the numerous claimants and their countless claims to see whether perhaps, this time, the magical mileage elixir or perpetual-motion machine is real.

The fact that Canadian Tire sell this product indicates, I think, that Canadian Tire reckon people will buy it. Similarly, Wal-Mart sells those magical "Power Balance" wrist bands (and several similar products, not to mention a particularly spiffy-looking magical engine potion).

And just about every pharmacy sells homeopathic remedies (as does Walmart!). And so on, and so forth.

Stop Worrying and Love the Global Warming

Why, what an unexpected pleasure in the post today. A bank statement, a copy of one of Australia's least interesting magazines...

Galileo Movement flier Galileo Movement flier

...and a leaflet from a bunch of climate-change deniers! The front of which is one spaceship away from being the cover of an Asimov book!

The current Australian Federal government, you see, is proposing a carbon tax, the cost of which to consumers (in the form of more expensive goods and services from organisations that now have to pay for their pollution) will be offset by tax cuts. Various people have objected to this, including this mob, "The Galileo Movement".

The very name of The Galileo Movement proclaims their proud dedication to the popular Galilean version of the association fallacy. They laughed at Galileo, you see, and he was right, so since they also laugh at you, that's evidence indicating that you must also be right.

But they also laughed at Bozo the Clown.

(It's a bit like a Christian organisation calling itself the Pascal Society.)

The "Patron" of the Galileo Movement is the entirely laudable colourful Australian radio personality Alan Jones. Jones, like most prominent climate-change deniers, is an authoritarian conservative, very wealthy, entirely without any relevant scientific education or perceptible respect for scientists who disagree with his views, and certain to be safely dead by the time the global climate really starts going to hell.

But never mind Alan. On to the "facts" presented by this flier:

* CARBON DIOXIDE IS NOT A POLLUTANT: CO2 is a colourless and odourless atmospheric trace gas. It is essential for life on Earth.

Well, I can't argue with that. Obviously nothing can possibly be bad if it has no odour. And the dose could not possibly make the poison.

I cannot imagine why they bothered putting any more "facts" on this leaflet, having led off with a humdinger of an argument like this one.

* RESEARCH: Studies of data over very long periods confirm that C02 increases came AFTER increases in global temperature. So CO2 could not have CAUSED past periods of planetary warming.

Or, to put it another way, it could.

The little nugget of information that's missing here is that higher CO2 causes warming, but warming also causes the release of more CO2, from sources like thawing tundra. (This is happening, alarmingly rapidly, today.) So CO2 peaks can actually be expected to come after temperature peaks.

Oh, and note that here, the nice Galileo people are saying that scientists are right about past temperature and CO2 levels, though they kind of gloss over what the scientists actually say.

We don't, actually, have very good data on global temperature in the distant past, because nobody was there to record it. We can get a good idea of the composition of the atmosphere many thousands of years ago by sampling air trapped in thick ice sheets, but we cannot get a similarly sharp view of the temperature. We have to use "proxies", like the width of tree rings.

If a climate-change denier's trying to build an argument that relies on old temperature numbers being inaccurate, expect him to have a lot to say about unreliable temperature proxies.

* WARMING: Some global surface warming probably has occurred in the last century. However. despite increasing atmospheric C02, there has been no increase in the global surface temperature since 1998.

...and now they're saying scientists are wrong about present temperatures. Except not really, because they slip in that "since 1998" when they think you're not looking.

Climate-change deniers love 1998, because 1998 was unusually warm. So if you graph global temperature for the last, say, hundred years, you get a peak in 1998 and then it kind of plateaus off. At a temperature well above all previous temperatures.

Heck, the recent-temperatures graph actually goes down in a few places, like after 1940 and around 1990. Pretending that this is an actual argument against climate change, however, is like saying that Apple stock is a bad investment because it didn't do very well in 2008.

* CHINA: China produces the equivalent of Australia's total annual CO2 emissions in less than a month. Its total annual emissions will increase by 70% in the next decade to 10,000 million tonnes. Why should we sacrifice jobs and harm our economy, when our exported coal is being consumed tax-free there?

* REST OF WORLD: The Gillard Government wants to reduce our 1.5% of total global CO2 emissions. Yet China and the USA, the planet's two largest emitters, will CONTINUE TO INCREASE their emissions, together with India and most other countries.

This is the strongest argument available to climate-change deniers, and, notably, is also not actually an argument that denies that climate change is happening. One should not, indeed, expect to reduce atmospheric CO2 levels by reducing emissions from countries that don't emit that much CO2 in the first place. Especially while much bigger CO2 emitters are dramatically increasing their output.

This does not, however, mean that you shouldn't do the right thing, just because people elsewhere are doing the wrong thing on a greater scale. We're all going to have to do the right thing eventually, and rich countries like Australia can afford to be (relatively) early adopters, even if the actual direct effect of our action on the climate will be trivial.

This "why-bother argument" is, I think, analogous to the argument that voting is futile, because your one single vote will almost certainly never decide an election.

But it's not like voting, because reducing CO2 emissions is something that human societies are not very good at doing yet, so having a go at it will help us figure out which techniques work, and which don't. If humans all refused to do something because everybody else wasn't doing it yet, climate change wouldn't be a problem at all, because we'd never have figured out how to light a fire.

* NATURAL ICONS: The governments tax will not make any difference to the state of the Great Barrier Reef or Kakadu ~ both of which are environmentally healthy.

This one's a bit bloody cheeky.

The Great Barrier Reef has indeed pretty much recovered from the last major bleaching event in 2006, and clearly that's not going to happen again. I mean, it's only happened seven times since 1980, most seriously in 2002 and, yes, good old 1998.

Using this same argument, we can conclude that Australia need not worry its pretty head about bushfires any more, either!

(Note also the "I'm all right, Jack" attitude to coral reef destruction; it's uncontroversial that warmer seas correlated with mass bleaching events - which is why unusually-warm 1998 was so bad for reefs - and it's similarly uncontroversial that there are reefs all over the world that are in danger as a result. But as long as our big reef's OK, who cares?)

And yes, the Kakadu National Park does not, at present, seem to be suffering any particular climatic damage. It seems pretty likely that it will, but just because there's a man with a machete climbing in through your window is no cause for alarm. Give the fellow a moment to explain himself.

There are plenty of other forested areas in the world that are currently doing OK, too. I doubt that a lawyer would achieve much success if he argued that his client should be acquitted because, yes, OK, that incident with the machete was unfortunate, but look at all of the people in the world that he clearly has not yet murdered!

The whole point of action on climate change is to do something about it before our national parks dry out or wash away, our farmland blows into the ocean, yet more misery and death is visited upon millions of brown people we don't much care about, et cetera.

* CLIMATE CHANGE: Climate change is a natural phenomenon. It is not due to human activity. The frequency of Australia's floods, droughts, bushfires and cyclones will not be controlled by a new tax.

If this is actually true, then all of the other stuff is irrelevant.

It's sort of kettle logic - "I did not break your kettle! It was in one piece when I returned it! And the holes were already in it when I borrowed it! And I never borrowed your stupid kettle anyway, so there!"

I suppose they could have phrased it as "even if we're wrong about all this other stuff...", but that'd clash a little with their proud dedication to FACTS!, so they're stuck with these arguments that sit strangely together.

But never mind, because this one's no good, either.

CO2 is definitely a greenhouse gas.

CO2 levels are definitely much higher now than they've been for hundreds of thousands of years.

This change is definitely the result of human activity since the Industrial Revolution. The numbers are very bloody clear indeed.

All the deniers are left with is claiming that this CO2 will, for some reason, not do anything. Good luck with that.

* FUTURE: Climate model predictions of dangerous global warming are highly uncertain, as there are no established laws of climate change.

Whoops, there we go - now the scientists don't know anything, again!

It's true that we don't know exactly what climate change will do. Shifting climate will probably make some deserts bloom. Which is all very well if you own the bloody desert, but a bit of a problem if you're trying to farm a place where it doesn't rain any more. And a warmer climate is a more energetic climate with more water in the atmosphere, which most certainly does mean more cyclones and floods, though not necessarily more droughts and bushfires.

You don't need a full and accurate model of everything that might happen for the next hundred years to realise that we're changing the climate in surprisingly large ways. My personal favourite example is the sodding Northwest Passage, which is now navigable every summer. At the beginning of the 20th century, the preferred vehicle for traversing that area was the dog-sled; today, it can accommodate commercial freighters.

But oh, no; climate change isn't happening and if it is then it doesn't matter and if it does then it's not our fault and if it is then there's nothing we can do. You can't prove that any particular natural disaster was definitely the result of climate change; therefore, there's nothing to worry about.

And companies like poor little BHP, trying to somehow survive with only the biggest profit they've ever made standing between them and penury, must not be taxed even a tiny bit more or they'll lay everybody off.

Sheesh.

Attack of the Radioactive Walking Shoes

A reader writes:

So....At times things eat at my mind, it makes me good at some things, but at other times it just stresses me out. I thought you might have a point of view that would be reasonably sane on my dilemma. Though I acknowledge it's something that is far from your field of expertise, but you may have an idea... Just because radioactivity is cool.

So my flatmate visited Chernobyl. I thought that was kind of cool, but we somewhat agreed they'd discard their shoes and clothes afterwards (see where this is going? ;)

The tour got pretty close, they were standing within 100m of reactor 4. The digital Geiger counter was registering 4 mSv/h (I zoomed in on a photo.... will check that again at some point). Most of the tour group stayed on paved ground, though in some places quite broken. A few ignored the tour guides and were wandering around on the somewhat radioactive grass at one point near reactor 4. They ate at a nearby cafe, visited some of the local sites driving around in a small bus, then left the exclusion. On leaving they each went through some kind of radiation measuring device, it looked like a big metal arch, you put your hands on the sides of a console at head height and your face was pretty close to something, no one set that thing off. Though no one was really sure what it was measuring, or if your shoes were included.

Said flatmate spent another week travelling before returning to Australia, along with their Chernobyl clothes and shoes. The tour operators seem to think no special precautions needed to be taken with clothes and shoes after leaving.

Do you think particulate matter bought back poses a health risk worth worrying about? I made them leave their shoes outside the house....But on their clothes packed in the same bag as their shoes, it seems inevitable that some radioactive isotopes have made it inside. Though, they're only a problem if I inhale or digest them, damn cesium. I do acknowledge that I'm already host to unstable isotopes of carbon in measurable amounts.

I recently, fortuitously, bought a nice enough Miele vacuum cleaner which I hope effectively implements its HEPA filter.

Unfortunately I'm cynical enough about our own government's competence to have serious doubts as to whether the Ukrainian government has enforced effective safety procedures. Especially given the USSR's history at this site...

Roscoe

Summary, before I start talking about ways in which radiation can kill you horribly: Radiation is almost certain not to kill you horribly. Those clothes, especially the shoes, may be detectably contaminated, but they're very unlikely to be dangerously contaminated. And if they've been worn and washed a few times since the visit, contamination may not even be detectable any more. Even if you did big shoe-fetishist sniffs all over your flatmate's sneakers as soon as they got home, you'd probably still be at much greater risk from everyday non-radioactive air contamination.

Like you, I wouldn't have much faith in the dedication of Ukrainian Chernobyl-tour outfits to customer safety. Lord knows the Western world's airports are now full of staggeringly expensive "security" hardware that doesn't bloody work at all, so a country with a GDP per capita a sixth that of Australia, and with the usual ex-Soviet wall-to-wall government corruption, could be worse. But the tours are a regular event now, so even the defective imaginary-terrorist-obsessed Western world's governments would probably have noticed people coming back with shoes that glow in the dark.

Plus, I'm sure plenty of people have taken their own Geiger counters with them on these tours, and yet the most newsworthy result of a trip to Chernobyl remains that chick who pretended to have taken a solo motorcycle tour.

On the subject of Geiger counters, I think it's important to mention that if you decide to get yourself your very own ionising-radiation meter, be aware that there are two basic kinds on the consumer market. Both may be sold as "geiger counters", but only one of them is.

A geiger counter can measure low levels of radiation. You can, for instance, use a geiger counter capable of detecting alpha particles (which many can't) to verify that a lump of unremarkable granite measures above (but probably nowhere near dangerously above) the background level of radiation. (Unless your house is built on granite!)

The other kind of radiation meter is the "ion-chamber survey meter", which is much less sensitive. If the needle on a survey meter ever budges, you should get the hell out of there. Survey meters are only meant to be used in places with high radiation levels, like serious nuclear accidents or after an actual nuclear war.

A lot of cheap eBay radiation meters are the distinctive yellow US Civil Defense versions, which come in geiger and ion-chamber versions. If it's pleasingly cheap, it's probably a useless ion-chamber meter.

(Note also that if Australians buy a geiger counter from overseas, it may not make it through Australian Customs, especially if it comes with a mildly radioactive calibration object.)

It is unlikely that any Chernobyl/Pripyat tours go anywhere remotely hot enough to get a reading from an ion-chamber meter, though you may be able to see places that'd be hot enough, like the secured, deserted scrapyards where they parked the emergency vehicles used during the disaster, or particularly choice parts of the Red Forest.

And yes, dirt or otherwise broken ground around Chernobyl is in general more radioactive than hard surfaces, because rain washes particulates off roads and footpaths and buildings onto soil, where they accumulate. Chernobyl is a particularly delightful test case for this phenomenon, because the combination of the reactor's design and the astonishing fuck-ups that led to the disaster meant that the Chernobyl accident caused a roaring fire in its graphite moderator, spewing a vast plume of radioactive smoke into the sky and raining particulate fallout over a huge area.

(The far less disastrous Windscale fire happened in a graphite-moderated reactor too, but it was the fuel burning that time, not the moderator.)

The recent TEPCO disaster in Japan has released an amount of radioactive material comparable with Chernobyl. The Fukushima Daiichi reactors don't have much burnable stuff in them, though, so most of the escaped isotopes are just sitting around in the neighbourhood of the reactors, or washed away into the ocean where tedious scientists say they're diluted out of significance but we all know they'll really wake up Gojira.

I am, of course, kind of winging it on this answer, because I am indeed not what you'd call an expert on the particular perils of tramping around in the Zone of Exclusion. (I'd probably walk straight into an anomaly and die.) I invite readers to tell me what I've overlooked, and thereby scare the tripes out of Roscoe.