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Pondering Heat Stress and Dosimetry

Stay hydrated, get some shade, and take breaks.

The original dosimeter was made to detect radiation exposure. The original types, disposable, worked by making it apparent how much chemical change had resulted from ionization. Modern radiation dosimetry uses electronic sensors to achieve the same purpose, but are more accurate and reusable. (See OSHA: “Ionizing Radiation”: Dosimeters.)

There are also dosimeters for noise. They detect how much loud noise a worker is subjected to over time, in order to help protect their hearing. (See OSHA: “Occupational Noise Exposure”.)

And there is dermal dosimetry, which isn’t broadly developed, but is meant to measure how much of some environmental contaminant or toxin gets deposited on a worker’s skin. (See OSHA: “Dermal Exposure”.)

But I haven’t found much about heat dosimetry. (See OSHA: “Heat Illness Prevention” for general information about occupational heat stress.)

The labor problem of extreme heat may require the creation of a new type of dosimeter. This might be called thermal dosimetry, but that already refers to quantifying how much heat a medical patient receives in therapeutic hyperthermia—the use of heat to treat cancers.

Heat dosimetry would need to monitor a person’s time in environments that harm their body’s ability to regulate temperature. It’s a complex problem, which has been avoided in favor of self-monitoring and following general guidelines (access to shade, water, and breaks; monitoring environmental conditions generally, including sunlight and the heat indexed temperature).

It is somewhat complicated by the concept of acclimatization. People who are exposed to hot environments see their bodies adapt to be better suited to work in those environments. A gradual increase in exposure over a week or two makes the body better at sweating and maintaining body temperature in hot environments. (See CDC: NIOSH: “Heat Stress Acclimatization”.)

Would a theoretical heat dosimeter need to be calibrated or toggled for acclimatization? Only to a point. There are limits to how well the body can adapt to extreme heat and humidity, and so at levels beyond those, measuring strict exposure time would be enough.

Heat is a combination of several factors. Air temperature is the most obvious, but sun exposure and humidity are very important as well. There is also the surroundings, what the person wears, general fitness, and acclimatization. Finally, the type of activity the person engages in has a major effect in how rapidly they heat up.

If a heat dosimeter existed, it would need at least three components. One would monitor sunlight, another ambient temperature, and the third would measure humidity. Some reference values would be needed, but calculating the heat index with an adjustment for sun exposure would probably add up to a basic dose-check that could be used.

Unlike other exposure dosimeters, the big difference with heat is rapid recovery time—if the person has not been overexposed. While radiation, noise, and toxins provoke absolutely cumulative harms, heat exposure (up to a limit) can be tolerated with rest and removal from bad conditions. That’s an argument both in favor and against using dosimetry: it’s a recoverable condition, and regular breaks with relief from the heat are sufficient protection, but if only vitals are monitored, waiting for warning signs may be harmful.

On the other hand, measuring symptoms might work better than the traditional dosimetry approach. Monitoring the heat stress symptoms of the person may prove a better fit than trying to treat the problem like typical exposure dosimetry. That would include heart rate, body temperature, and hydration level.

Measuring acclimatization is important as well, and could probably be derived from the other measures. A person’s level of acclimatization can vary from day to day, depending on other stresses they may be under (including how much sleep they’ve had, dietary fluctuations), so acclimatization shouldn’t be treated as a binary.

Better heat-monitoring tools are definitely needed. Whether it’s practical or desirable to monitor exposure to environmental heat remains to be seen. Monitoring vitals directly, rather than exposure, has the benefit of alerting to other conditions and issues. Having regular breaks and access to adequate shade and cold water are enough to prevent most heat issues up to a point. Beyond that point, measuring heat doses may be important.

There are other alternatives to working in hot environments. Night work or temporarily and partially conditioned environments may be possible, but come with their own challenges. Night shifts cause sleep-related stresses and has some extra costs associated with it. Partial conditioning of a work environment requires extra labor and costs. How those costs stack up against working with heat isn’t clear.

For example, installing fixed poles for stretching tarps or canopies over a field to provide shade during fieldwork might be a practical mitigator for farms. Roadwork can benefit from night shifts, as it reduces traffic woes as well.

All that being said, it’s likely some companies have or will explore heat dosimetry. And it’s likely that at least some workers would benefit from it, even in the presence of direct monitoring of their vital signs and health. It will be interesting to see what the devices look like and how they operate.

It’s sure that the world is getting hotter from climate change, and we have to keep looking for ways to adapt.

Earth Day 2022

Another year in the books for the planet we all call home.

Please register to vote ( Please vote for candidates who will fight carbon pollution.

Month after month, year after year, we read about the climate crisis. The greenhouse effect was taught to me in school so long ago I barely remember the teachers’ names. And every year more carbon goes up, while many politicians still do not take the problem seriously.

Even as we face catastrophe, we learn the fascinating bits: how tree rings can tell us wet and dry years, or how layers of sediment in the oceans hold tiny shells that confess the atmosphere of their day, as do bubbles trapped in polar ice. (See Wikipedia: “Paleoclimatology”: Proxies for climate.) And it feels like sitting in a doctor’s office, being told of the scans and chemistries used to diagnose us, the doctor waving a slide rule as they tell us our odds of survival from a cancer or a heart attack unless we make a change.

We learn when distant cities will be underwater. How they will be flooded, first during storms, then tides. After that it won’t be flooding, it will have become part of the sea. There are maps showing the water moving in, from a centimeter every few years to a centimeter every year and beyond, if the carbon keeps flowing. The waters will skip the hills and makes them islands, for awhile anyway. If the waters keep going up, the new islands will be drowned. We see an artist’s rendering of what a mall looks like under ten feet of water.

The other disasters: major hurricanes, tornadoes, wildfires, the arctic vortex, droughts and floods. The own-goals: deforestation, methane leaks. And all the tips for reducing our carbon footprints. Less meat, reusable bags, changing lightbulbs, recycle, buy used. The media talks them up and then moves on to the latest politics, celebrity. We forget long enough to feel better, partying between hangovers.

The people making decisions aren’t worried, because they’re not paid to cut carbon. They’re paid to make sales. There are few jobs on the planet where the compensation goes up if the carbon goes down. They are renewable electricity generators, mostly. But the world has not put a price on carbon pollution. If it did, most everyone would earn more by cutting carbon, and the crisis would end. That’s the theory.

For those selling carbon offsets to wealthy people seeking to allay their guilt, there’s no extra money for lower carbon. Car makers don’t get a better price for making a more efficient car (though in some markets their days to sell carbon-powered vehicles are numbered). Oil drillers don’t have to pay for venting methane, as farmers don’t pay more for wasting water.

On Earth Day 2022, the situation looks the same as it has for decades. There are some modest efforts, far short of what’s needed. At the rate we are going, we will reach carbon neutrality later than needed, but we will get there. Not so optimistic, but not so pessimistic. We’re betting that knock-ons won’t turn out worse, that there’s no domino effect that will push us over a cliff.

It all feels like a missed opportunity, a lucrative one that the business community and the politicians were too dumb to take up. One that many of them agitate against out of some bizarre obligation to a sick system. There are many solutions that all miss the mark in one key area: the votes needed to pass anything.

Please register to vote ( Please vote for candidates who will fight carbon pollution.

Not a War–a Fire.

A fire is a better metaphor for pandemics than a war.

Lots of metaphors around these days. Fire is one of the better ones. Fire spreads; disease spreads. Fire is dangerous; disease is dangerous.

War doesn’t spread the same way, though its devastation does. It’s more targeted. It is man-made.

Nobody says, “Let’s let the fire burn, we can’t shut the economy down because of a little fire.” Good people don’t offer up grandparents in immolation.

The administration’s response to the fire, to the disease, has not been good. It has gotten marginally better, but threatens to get worse again. The response, and the disease. Which is the big problem with letting a big-time loser direct the fire department. Not good.

Places that do not heed the basic rule of fire safety—deprive it of fuel—will be scorched worse than those places that do. For a disease, human contact is spreading the embers to new fuel.

With developed diseases, like influenza, we have vaccines. That’s a controlled burn or a fire break. Sets some distance. People still get flu, but we try to make it harder for that particular fire to spread. With this new fire, it will take time to develop a vaccine. So we have to spread the fuel apart—social distancing.

As with fire, this disease will spread to any fuel it can reach. Different houses will burn differently. Some will be spared, others will collapse. These are human lives we’re talking about.

You don’t reopen until the fire has abated, until it’s under control. You don’t mess around with fire. Places that do will, with high probability, get burned. Already, due to Donald John Trump’s errors of judgment, more are sick than should be. And some probably getting sick because of his unfounded optimism. All these Republicans who have downplayed the threat, and their counter-culture media drones, they’re fanning the fucking flames. Morons.

Anyway, stay safe out there. Be thankful for the mail carriers, the doctors, the grocery workers, and, yes, the firefighters. Right now they’re all firefighters.

Donald John Trump is a firebug. Don’t listen to his lies. His job is to make sure all those firefighters are equipped, and that we’re doing all we can to stop the spread, but he’s not. That’s a failure.

As a side note, the term shelter-in-place refers to an immediate stoppage of nonessential movement during an acute emergency. Basically, during a shelter-in-place situation, unless the danger to you is greater where you are than the risk of moving, you shouldn’t. It applies to wherever you happen to be at the time of the order.

The orders being issued aren’t correctly described as shelter-in-place. They are stay-at-home. Nobody expects someone to start living out of their local gas station if that’s where they are right now. During a real shelter-in-place, one would be expected to stay at the gas station until the immediate danger had abated and the order lifted.