How much skin cells are in dust

Do you feel "comfortable inside your skin," as the saying goes? Well, just wait a few hours. You may feel like your skin is a permanent part of you, but in fact, the body is constantly replacing its billions of skin cells as they wear out. Every hour, you lose over half a million dead skin cells. In fact, eight hundred of the little guys just flaked off while were reading this sentence.

So it seems plausible, right, the common claim that as much as 80 percent of household dust is human skin? There is organic material in dust—all that discarded "you" has to go someplace—but it turns out that there's so much tiny stuff floating around your room about 10 million particles in every cubic meter of household air!

They know that consumer products—vinyl flooring, personal care products, electronics, furniture, carpet pads, paints, cleaning products, and more—have a strong driving force to shed compounds into materials with lower concentrations of the substances. For example, a flame retardant might volatilize off the plastic parts of a TV set into the air, stick onto airborne particles, and move into dust, which settles on floors and carpets.

The compounds will continue to migrate until they reach equilibrium with the surroundings, says Diamond. And heating the product, such as turning on a computer, also speeds migration into the home environment; a compound will condense in a cooler part of the room, where dust often resides. For instance, if dust settles onto a TV set or Wi-Fi router, there is a very good chance that flame retardants will migrate directly into the dust.

With people in the room, things get even more complicated. Stapleton , an environmental chemist at Duke University. Most research has focused on identifying individual classes of compounds in dust, like the polybrominated diphenyl ether PBDE flame retardants found in furniture foam, carpet pads, and electronics; phthalates such as those found in vinyl flooring ; or pesticides tracked in on shoes or evaporated off pet collars.

Now, researchers are trying to get a more comprehensive view of the mixtures people are exposed to by probing the overall contaminant load in house dust. By combining toxicity tests with emerging methods for determining a complete profile of compounds in dust, researchers may be able to determine what chemicals or combinations of chemicals are most toxic, Stapleton says. In one new approach, scientists combed through two dozen dust studies of 45 compounds to create a snapshot of nationwide exposures, says Robin E.

Dodson , an exposure scientist at the Silent Spring Institute. She and Veena Singla , a staff scientist at the Natural Resources Defense Council, ranked the substances according to the amount in dust and estimated intake and health hazard. The phthalate plasticizer di 2-ethylhexyl phthalate, known as DEHP, topped the list. Phthalate plasticizers make plastic more pliable and are found in vinyl flooring, food containers, and cosmetics.

DEHP can disrupt hormone function in human and animal studies and is linked to reduced sperm motility in men. Other compounds on the list include phenol preservatives found in deodorants and cosmetics; flame retardants; a fragrance compound known as Galaxolide, or HHCB; and perfluorinated stain repellents Env.

What all this means for health is a sticky question. For some compounds, such as PBDEs, researchers have shown that dust is a major source of human exposure to these potentially endocrine-disrupting chemicals. After she and Dodson completed their study, she compared the amounts of contaminants in dust to soil-screening thresholds set by the Environmental Protection Agency that indicate a chemical might pose health risks and thus require further investigation.

She found that the concentrations of some phthalates and flame retardants in house dust exceeded these standards. Her lab found that flame retardants will bind to a human cell receptor that triggers fat storage in human cells. Todd P. Whitehead, an environmental scientist at the University of California, Berkeley, is part of the California Childhood Leukemia Study that aims to identify the risk factors for the disease, which has become more common since He and his team are sampling dust in California homes because his work shows that dust is a useful indicator of exposure to polycyclic aromatic hydrocarbons PAHs , PBDEs, and PCBs, compounds that are suspected leukemia risk factors.

And there are other sources of exposure to these compounds whose importance relative to dust is unknown. Until now, technology has constrained scientists to study just the few hundred compounds that they know are in dust and for which they have analytical standards. Furthermore, these compounds account for only a small fraction of the toxicity found in tests of household dust.

So scientists reason that a substantial number of unknown contaminants in dust exist that could pose health risks. The strategy combines high-resolution mass spectrometry with data processing tools to tease out the identities of chemicals from a mass of data. Nontargeted analysis has revealed that chlorinated paraffins, nonylphenol ethoxylates, and azo dyes, many built using 2-bromo-4,6-dinitroaniline as a backbone, are major components of household dust.

Ferguson and his team recently took extracts of household dust, separated the extracts into fractions using high-performance liquid chromatography, and then analyzed each fraction with ultra-high-resolution mass spectrometry. This process generates up to 10, candidate molecules, Ferguson says. Using those data, patent information, and literature references, the researchers prioritize the likelihood of compounds to be in dust samples.

These are nonionic surfactants used in household cleaners—and suspected endocrine disruptors. The team is working to get standards for these compounds to confirm their identity and quantify them in dust, he says. And Cynthia A. This large class of compounds acts as flame retardants, plasticizers, and lubricants for metal parts, appearing in caulking for buildings and windows and even in handheld kitchen mixers. These new findings are just the start, researchers say.

In fact, an international collaboration aims to pick apart dust to get its complete profile, says Pawel Rostkowski , an environmental chemist at the Norwegian Institute for Air Research. They will aggregate the results to build an open access library of mass spectra for the thousands of compounds they hope to identify. A new California law requires all labels on upholstered furniture to declare the presence or absence of added flame retardants.

But she adds that ultimately, safety testing needs to be done before, not after, compounds are added to products—before they even have the chance to turn into dust. Janet Pelley is a freelance writer. Contact us to opt out anytime. Contact the reporter. Submit a Letter to the Editor for publication. Engage with us on Twitter. The power is now in your nitrile gloved hands Sign up for a free account to increase your articles.

Or go unlimited with ACS membership. Chemistry matters. Join us to get the news you need. Don't miss out. Renew your membership, and continue to enjoy these benefits. Not Now. Many people claim to be allergic to dust, but in many cases they are actually having an allergic reaction to dust mites. These mites eat the dead skin and their dead bodies and fecal matter cause allergic reactions in people. Up to dust mites can survive on just 1 gram of dust.

Depending on how small the particle is, dust is capable of staying suspended in the air for up to 5 days. The Sahara desert is the largest source of dust in the entire world, and million tons of dust from this desert blows across the Atlantic Ocean to South America, where it fertilizes the Ocean and the Amazon rainforest. While the Sahara is the largest source of atmospheric dust, an estimated 5 billion tons of dust is transmitted through the atmosphere each year.

This dust can affect air temperatures, ground cooling, and rainfall levels, and is monitored closely by NASA. This airborne dust also helps to create a cloud condensation nucleus that allows water droplets to form in clouds. When these water droplets get heavy enough, they fall to the ground as rain. Inside every raindrop is a piece of dust! The same goes for snowflakes. Each year the Earth gains about 40, tons of cosmic dust that falls on it from space in the form of micrometeorites.