TOXIC BENZENE AND PARKED CARS - Benzene is a toxic chemical known to produce a variety of ill health effects, including anemia and cancer (specifically leukemia) in humans. The substance occurs both naturally and as a byproduct of human activities, e.g. as a component of petroleum-based products and products manufactured using benzene as a solvent (such as plastics, synthetic fibers, dyes, glues, detergents, and drugs). It's also a constituent of tobacco smoke. Low levels of benzene are typically present in outdoor air due to automobile exhaust and industrial emissions. Thanks to vapors emitted by household products such as glues, paints, and furniture wax, even higher levels of benzene can sometimes be found in indoor air, especially in new buildings. In most cars, these items are made from plastics, synthetic fabrics, and glues, some of which are manufactured using benzene. Such items may "off-gas" trace amounts of benzene, especially under hot weather conditions. As to car air fresheners, there's precious little information available about the ingredients, though one European study found that some household air fresheners emit measurable amounts of benzene. It's not inconceivable that some car air fresheners do, too. The crucial question is how much. Might all of these potential emitters cumulatively give off enough benzene to harm your health? Most of the published studies wherein benzene levels were measured inside passenger vehicles have been done in traffic. So, while such studies have indeed found that in-vehicle benzene levels can significantly exceed those outside the vehicle, and could pose a human health hazard, this is mainly attributed to the presence of exhaust fumes.

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Toxic Benzene and Parked Cars

by David Emery

This viral message claims car interiors contain toxic levels of cancer-causing benzene emitted by dashboards, car seats, and air fresheners, and recommends opening windows to expel trapped benzene gas before turning on the car air conditioner.

True or false?

·      Description: Online rumor

·      Circulating since May 2009

·      Status: Grain of truth / Overblown (see details below)

·      Example: Email text contributed by Glennis A., May 11, 2009:

Car A/C (Air Conditioning) MUST READ!!!

Please do NOT turn on A/C as soon as you enter the car.
Open the windows after you enter your car and turn ON the air-conditioning after a couple of minutes.

Here's why:

According to a research, the car dashboard, sofa, air freshener emit Benzene, a Cancer causing toxin (carcinogen - take time to observe the smell of heated plastic in your car).

In addition to causing cancer, Benzene poisons your bones, causes anemia and reduces white blood cells.

Prolonged exposure will cause Leukemia, increasing the risk of cancer. May also cause miscarriage.

Acceptable Benzene level indoors is 50 mg per sq. ft.

A car parked indoors with windows closed will contain 400-800 mg of Benzene. If parked outdoors under the sun at a temperature above 60 degrees F, the Benzene level goes up to 2000-4000 mg, 40 times the acceptable level...

People who get into the car, keeping windows closed will inevitably inhale, in quick succession excessive amounts of the toxin.

Benzene is a toxin that affects your kidney and liver. What's worse, it is extremely difficult for your body to expel this toxic stuff. So friends, please open the windows and door of your car - give time for interior to air out - dispel the deadly stuff - before you enter.

Our Analysis

While it isn't one hundred percent false, the above text is a font of misinformation. Don't let it scare you.

Starting with the basics, it's true that benzene is a toxic chemical known to produce a variety of ill health effects, including anemia and cancer (specifically leukemia) in humans.

The substance occurs both naturally (mainly as a component of crude oil) and as a byproduct of human activities, e.g. as a component of petroleum-based products (such as gasoline) and products manufactured using benzene as a solvent (such as plastics, synthetic fibers, dyes, glues, detergents, and drugs).

It's also a constituent of tobacco smoke.

Low levels of benzene are typically present in outdoor air due to automobile exhaust and industrial emissions.

Thanks to vapors emitted by household products such as glues, paints, and furniture wax, even higher levels of benzene can sometimes be found in indoor air, especially in new buildings.

Benzene in Cars

Do automobile dashboards, door panels, seats, and other interior components emit benzene, as claimed in the email?

Most likely.

In most cars, these items are made from plastics, synthetic fabrics, and glues, some of which are manufactured using benzene.

According to scientists, such items may "off-gas" trace amounts of benzene, especially under hot weather conditions.

As to car air fresheners, there's precious little information available about the ingredients, though one European study found that some household air fresheners emit measurable amounts of benzene.

It's not inconceivable that some car air fresheners do, too.

The crucial question is how much.

Might all of these potential emitters cumulatively give off enough benzene to harm your health?

What the Scientists Say

Most of the published studies wherein benzene levels were measured inside passenger vehicles have been done under driving conditions, in traffic.

So, while such studies have indeed found that in-vehicle benzene levels can significantly exceed those outside the vehicle, and could pose a human health hazard, this is mainly attributed to the presence of exhaust fumes.

Also, the amounts of benzene actually detected by researchers, albeit statistically significant, were much, much smaller than the amounts stated in the email.

A 2006 study summarizing all the data collected to date reported in-vehicle benzene levels from exhaust fumes ranging from .013 mg to .56 mg per cubic meter — a far cry from the 400 mg to 4,000 mg per square foot (do they mean cubic foot?) reported in the email.

Benzene Levels in Parked Cars

In the one study, we were able to find that measured benzene levels inside parked cars with their engines turned off.

The results were more benign.

Toxicologists took samples of the air inside both a new and a used vehicle under simulated hot-sunlight conditions, measuring the levels of volatile organic compounds (VOCs) including C3- and C4-alkylbenzenes, and exposing human and animal cells to the samples to determine their toxicity.

Despite the detectable presence of VOCs (a total of 10.9 mg per cubic meter in the new car and 1.2 mg per cubic meter in the old car), no toxic effects were observed.

Apart from noting the slight possibility that allergy-prone individuals might find their condition exacerbated by exposure to such compounds, the study concluded there is "no apparent health hazard of parked motor vehicle indoor air."

When in Doubt, Ventilate

Despite this finding, some drivers may still be concerned about the presence of any benzene vapors inside their car, especially given the World Health Organization's stated position that there is "no safe level of exposure" to the carcinogen.

They may also worry, per the email warning above, that turning on the vehicle's air conditioner might exacerbate their exposure to trapped toxins by recirculating contaminated air.

If that's the case, there's no harm done — and much peace of mind to be gained — by simply opening the windows and ventilating the car before turning it on.

David Emery is a freelance writer and avid chronicler of folklore and popular culture, with a special interest in the quick-fire folklife of the digital age.

Experience

Dubbed About.com's "urban legend guru" by Salon magazine and cited in the New York Times, Christian Science Monitor, Washington Post, the BBC and USA Today, David Emery has more than 18 years' experience as an Internet folklore expert and debunker of urban legends, hoaxes, and popular misconceptions. Other professional credits include stints as a newsroom librarian, staff writer for a TV sitcom, freelance journalist, and contributing editor of a satirical newspaper. Mr. Emery first won recognition in the online universe as an arch commentator on the outer limits of Net culture with Iron Skillet Magazine, "a compendium of offbeat views run through the blender of the author's savage sense of humor ... [with] on-target skewerings of strange ideas" (Houston Chronicle, 1997).

Testimonials

“[Emery is] a strong writer with a bright, amusing style. This fun, informative, and concise site is extremely easy to navigate and a good first step for those new to the subject.” – Brandon Toropov, The Complete Idiot's Guide to Urban Legends (Alpha Books, 2001)

“The best place to track urban legends is the About.com section run by guide David Emery. In addition to his usual smart debunking of various urban legends, he has been tracking rumors about the attacks since Sept. 11. “ – Sree Sreenivasan, “Keeping Track of Rumors and Hoaxes” (Poynter.org, 2002)

“This About.com subsite has been hosted for ten years by David Emery and frankly, he has done a great job. He is passionate about finding and debunking all those rumors, myths, pranks and odd stories. “ – Tim Malone, “Top 10 Sites to Debunk Urban Legends" (Tech Republic, 2008)

"David Emery's urban legend site at About.com has been a reliable source of information for years." – Jan Harold Brunvand, Encyclopedia of Urban Legends, Updated and Expanded Edition (ABC-CLIO, 2012)

Education

Mr. Emery holds a BA in Philosophy.

David Emery

Please join me in what promises to be a constantly entertaining, ever-enlightening exploration into the urban legends and folklore of the digital age.

https://www.thoughtco.com/is-there-toxic-benzene-in-parked-cars-3298894

AIR POLLUTION - The term "air pollution" is used so commonly that you may not think definitions are necessary. Some sources define smog as the presence of unnatural levels of ground-level ozone, while other sources say things like "fog mixed with smoke." A more modern and precise definition is "a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust." Officially, air pollution can be defined as the presence of harmful substances in the air, either particulates or microscopic biologic molecules, that pose health hazards to living organisms, such as people, animals or plants. Air pollution comes in many forms and may include a number of different pollutants and toxins in various combinations. Air pollution is far more than a nuisance or inconvenience. Air pollution causes the deaths of approximately 4.2 million people annually worldwide. The two most widespread types of air pollution are the ozone and particle pollution (soot), but air pollution also may include serious pollutants such as carbon monoxide, lead, nitrogen oxides, and sulfur dioxide, volatile organic compounds (VOCs) and toxins such as mercury, arsenic, benzene, formaldehyde, and acid gases. Most of these pollutants are man-made, but some air pollution is due to natural causes, such as ash from volcanic eruptions.

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Air Pollution

What Is Air Pollution?

Definition, Facts, and Environmental Risks

By Larry West

The term "air pollution" is used so commonly that you may not think definitions are necessary. But the issue is more complicated than it first appears. 

Ask most people to define air pollution, and their first response is to describe smog, the smelly stuff that turns the air brown or gray and hovers over urban centers like Los Angeles, Mexico City, and Beijing.

Even here, though, definitions vary.

Some sources define smog as the presence of unnatural levels of ground-level ozone, while other sources say things like "fog mixed with smoke."

A more modern and precise definition is "a photochemical haze caused by the action of solar ultraviolet radiation on atmosphere polluted with hydrocarbons and oxides of nitrogen especially from automobile exhaust."

Officially, air pollution can be defined as the presence of harmful substances in the air, either particulates or microscopic biologic molecules, that pose health hazards to living organisms, such as people, animals or plants.

Air pollution comes in many forms and may include a number of different pollutants and toxins in various combinations.

Air pollution is far more than a nuisance or inconvenience.

According to the World Health Organization, air pollution causes the deaths of approximately 4.2 million people annually worldwide.

What Constitutes Air Pollution?

The two most widespread types of air pollution are the ozone and particle pollution (soot), but air pollution also may include serious pollutants such as carbon monoxide, lead, nitrogen oxides, and sulfur dioxide, volatile organic compounds (VOCs) and toxins such as mercury, arsenic, benzene, formaldehyde, and acid gases.

Most of these pollutants are man-made, but some air pollution is due to natural causes, such as ash from volcanic eruptions. 

The specific composition of air pollution in a particular location depends primarily on the source or sources of pollution.

Automobile exhaust, coal-fired power plants, industrial factories, and other pollution sources all spew different types of pollutants and toxins into the air.

While we think of air pollution as a condition describing outside air, the air quality within your home is equally important.

Cooking vapors, carbon monoxide from heating appliances, off-gassing of formaldehyde and other chemicals from furniture and construction materials, and secondhand tobacco smoke are all potentially dangerous forms of indoor air pollution. 

Air Pollution and Your Health

Air pollution hovers at unhealthy levels in almost every major U.S. city, interfering with people’s ability to breathe, causing or aggravating many serious health conditions, and placing lives at risk.

Many cities worldwide face the same issues, especially in so-called emerging economies such as China and India, where cleaner technologies are not yet in standard usage. 

Breathing ozone, particle pollution or other types of air pollution can seriously damage your health.

Inhaling ozone can irritate your lungs, "resulting in something like a bad sunburn within the lungs," according to the American Lung Association. Breathing particle pollution (soot) can increase your risk of heart attack, stroke and early death, and it may necessitate emergency-room visits for people with asthma, diabetes and cardiovascular disease.

A great many cancers are traced to chemical air pollutants. 

Air pollution is also a problem in developing countries that are not yet fully industrialized.

More than half the world's population still cook their meals with wood, dung, coal or other solid fuels over open fires or on primitive stoves inside their homes, breathing high levels of pollutants such as particulate pollution and carbon monoxide, which results in 1.5 million unnecessary deaths every year.

Who Is Most at Risk?

The health risks of air pollution are greatest among infants and young children, older adults and people with respiratory diseases such as asthma.

People who work or exercise outside also face increased health risks from the effects of air pollution, along with people who live or work near busy highways, factories or power plants.

In addition, minorities and people with low incomes are often disproportionately affected by air pollution because of where they live, which places them at higher risk for illnesses related to air pollution.

Low-income populations often live near industrial or inner-city zones where factories, utilities, and other industrial sources may create unusually high levels of air pollution. 

Air Pollution and the Health of the Planet

If air pollution affects humans, it of course also may also have an impact on animals and plant life.

Many animal species are threatened by high levels of air pollution, and weather conditions created by air pollution affect both animal and plant life.

For example, acid rain caused by the burning of fossil fuels has radically changed the nature of forests in the U.S. Northeast, upper Midwest, and Northwest.

And it is now indisputable that air pollution causes shifts in global weather patterns — the raising of global temperatures, the melting of polar ice sheets and the coming rise in ocean water levels. 

How Can Air Pollution Be Reduced?

The evidence is clear that our personal choices and industrial practices can affect the levels of air pollution.

Cleaner industrial technologies are shown to lower air pollution levels, and it can be demonstrated that anytime more primitive industrial practices increase, so do levels of dangerous air pollution.

Here are some of the obvious ways that humans can, and have reduced air pollution: 

o    Reduction of fossil fuel burning in favor of renewable energy sources. Nations that obtain their electrical power from nuclear, hydroelectric, solar and wind power have lower pollution levels than those that favor the burning of coal or natural gas. 

o    Improved gas mileage in automobiles and the introduction of electric-powered vehicles. California, for example, once plagued with dangerous smog, has greatly improved its air quality through tight controls on automobile emissions standards. Similarly, reduction in the use of other internal combustion engines can reduce air pollution. The shift to battery-operated or electric lawn mowers and lawn equipment, for example, has a demonstrable effect on air quality. 

o    Reduction in agricultural burning — the method of clearing forested areas for agriculture — can reduce the level of smoke and carbon dioxide in the air. This is a particular problem in developing countries. 

o    Reducing wood burning can also reduce levels of smoke in the air. In some communities, wood fireplaces are now outlawed, greatly reducing dangerous levels of smoke in the air. Gas fireplaces are better than wood-burners, and even better are electric fireplaces that burn no fuels at all. 

o    Indoor air quality is improved when tobacco smoking is restricted by ordinance. Citizen pressure to restrict smoking in public places has a real effect on air quality. 

o    Reduction of chemical compounds in paints, adhesives, and solvents has improved the quality of indoor and outdoor air. Always look for low VOC materials for home improvements, and where practical, opt for water-based rather than solvent-based paints and other materials. Look for carpets, fabrics, and furniture that don't off-gas dangerous fumes. 

Controlling pollution is possible, but it requires the individual and political will to do so, and these efforts must constantly be balanced with economic realities, as green technologies are often more expensive, especially when they are first introduced. 

Such choices are in the hands of each individual: for example, do you buy a cheap but dirty automobile or an expensive electric car?

Or are jobs for coal miners more important than clean air? 

These complex questions are not easily answered by individuals or governments, but they are questions that should be considered and debated with eyes open to the real effects of air pollution. 

Larry West

Environmental Journalist

Education

B.A., Journalism and Creative Writing, University of Washington

Introduction

Environmental journalist with 20+ years of experience

Winner, Edward J. Meeman Award for Environmental Reporting

Writer and editor for Go West Strategic Communications since 2002

Experience

Larry West is a former writer for ThoughtCo who contributed articles for five years. He is a principal and professional writer and editor for Go West Strategic Communications. He has written about environmental issues for leading newspapers, magazines, and online publications. 

During his 20-year career in newspapers, Larry was part of an investigative team whose work was a finalist for the Pulitzer Prize. He also received the Meeman Award for national environmental reporting from the Scripps Howard Foundation. Later, Larry served as press secretary and deputy chief of staff for a U.S. Representative and served as communications director for a U.S. Senator. He also managed public affairs for organizations including the Federal Aviation Administration, a global technology company, and one of the largest ports in the United States. In each of those positions, Larry was involved in environmental strategy, policy, and communications. 

Education

Larry studied journalism and creative writing at the University of Washington in Seattle, Washington. He also taught research and writing courses in continuing education programs at the University of Washington and the University of Alaska. 

Awards and Publications

While working as a journalist for "The Seattle Times," Larry's work was awarded the Edward J. Meeman Award for Environmental Reporting by Scripps Howard, and a finalist for the Pulitzer Prize.

ThoughtCo and Dotdash

ThoughtCo is a premier reference site focusing on expert-created education content. We are one of the top-10 information sites in the world as rated by comScore, a leading Internet measurement company. Every month, more than 13 million readers seek answers to their questions on ThoughtCo.

For more than 20 years, Dotdash brands have been helping people find answers, solve problems, and get inspired. We are one of the top-20 largest content publishers on the Internet according to comScore, and reach more than 30% of the U.S. population monthly. Our brands collectively have won more than 20 industry awards in the last year alone, and recently Dotdash was named Publisher of the Year by Digiday, a leading industry publication.

https://www.thoughtco.com/what-is-air-pollution-1204103

ODOR CHEMISTRY - Organisms that have a sense of smell detect molecules by special sensory neurons called olfactory receptor (OR) cells. In humans these cells are clustered at the back of the nasal cavity. Each sensory neuron has cilia that extend into the air. On the cilia, there are receptor proteins that bind to aroma compounds. When binding occurs, the chemical stimulus initiates an electric signal in the neuron, which transmits the information to the olfactory nerve, which carries the signal to the olfactory bulb in the brain. A person may recognize an odor and relate it to an emotional experience, yet might be unable to identify the specific components of a scent.

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Odor Chemistry

Aroma Compounds and Their Odors

All About Odor Chemistry

by Anne Marie Helmenstine, Ph.D.                                                                                       

An odor or odour is a volatile chemical compound that humans and other animals perceive via the sense of smell or olfaction.

Odors are also known as aromas or fragrances and (if they are unpleasant) as reeks, stenches, and stinks.

The type of molecule that produces an odor is called an aroma compound or an odorant.

These compounds are small, with molecular weights less than 300 Daltons, and are readily dispersed in air due to their high vapor pressure.

The sense of smell can detect odors are extremely low concentrations.

How Odor Works

Organisms that have a sense of smell detect molecules by special sensory neurons called olfactory receptor (OR) cells.

In humans these cells are clustered at the back of the nasal cavity.

Each sensory neuron has cilia that extend into the air. On the cilia, there are receptor proteins that bind to aroma compounds.

When binding occurs, the chemical stimulus initiates an electric signal in the neuron, which transmits the information to the olfactory nerve, which carries the signal to the olfactory bulb in the brain.

The olfactory bulb is part of the limbic system, which is also associated with emotions.

A person may recognize an odor and relate it to an emotional experience, yet might be unable to identify the specific components of a scent.

This is because the brain doesn't interpret single compounds or their relative concentrations, but the mix of compounds as a whole.

Researchers estimate humans can distinguish between 10,000 and one trillion different odors.

There is a threshold limit for odor detection. A certain number of molecules need to bind olfactory receptors to stimulate a signal.

A single aroma compound may be capable of binding to any of several different receptors.

The transmembrane receptor proteins are metalloproteins, probably involving copper, zinc, and perhaps manganese ions.

Aromatic Versus Aroma

In organic chemistry aromatic compounds are those that consist of a planar ring-shaped or cyclic molecule. Most resemble benzene in structure.

While many aromatic compound do, in fact, have an aroma, the word "aromatic" refers to a specific class of organic compounds in chemistry, not to molecules with scents.

Technically, aroma compounds include volatile inorganic compounds with low molecular weights that can bind olfactory receptors.

For example, hydrogen sulfide (H₂S) is an inorganic compound that has a distinctive rotten egg scent.

Elemental chlorine gas (Cl₂) has an acrid smell. Ammonia (NH₃) is another inorganic odorant.

Aroma Compounds by Organic Structure

Organic odorants fall into several categories, including esters, terpenes, amines, aromatics, aldehydes, alcohols, thiols, ketones, and lactones.

Here is a list of some important aroma compounds. Some occur naturally, while others are synthetic:

	Odor	Natural Source
Esters
geranyl acetate	rose, fruity	flowers, rose
fructone	apple
methyl butyrate	fruits, pineapple, apple	pineapple
ethyl acetate	sweet solvent	wine
isoamyl acetate	fruity, pear, banana	banana
benzyl acetate	fruity, strawberry	strawberry
Terpenes
geraniol	floral, rose	lemon, geranium
citral	lemon	lemongrass
citronellol	lemon	rose geranium, lemongrass
linalool	floral, lavender	lavender, coriander, sweet basil
limonene	orange	lemon, orange
camphor	camphor	camphor laurel
carvone	caraway or spearmint	dill, caraway, spearmint
eucalyptol	eucalyptus	eucalyptus
Amines
trimethylamine	fishy
putrescine	rotting meat	rotting meat
cadaverine	rotting meat	rotting meat
indole	feces	feces, jasmine
skatole	feces	feces, orange blossoms
Alcohol
menthol	menthol	mint species
Aldehydes
hexanal	grassy
isovaleraldehyde	nutty, cocoa
Aromatics
eugenol	clove	clove
cinnamaldehyde	cinnamon	cinnamon, cassia
benzaldehyde	almond	bitter almond
vanillin	vanilla	vanilla
thymol	thyme	thyme
Thiols
benzyl mercaptan	garlic
allyl thiol	garlic
(methylthio)methanethiol	mouse urine
ethyl-mercaptan	the smell added to propane
Lactones
gamma-nonalactone	coconunt
gamma-decalactone	peach
Ketones
6-acetyl-2,3,4,5-tetrahydropyridine	fresh bread
oct-1-en-3-one	metallic, blood
2-acetyl-1-pyrroline	jasmine rice
Others
2,4,6-trichloroanisole	scent of cork taint
diacetyl	butter scent/flavor
methylphosphine	metallic garlic

Among the "smelliest" of the odorants are methylphosphine and dimethylphosphine, which can be detected in extremely low amounts.

The human nose is so sensitive to thioacetone that it can be smelled within seconds if a container of it is opened hundreds of meters away.

The sense of smell filters out constant odors, so a person becomes unaware of them after continuous exposure.

However, hydrogen sulfide actually deadens the sense of smell. Initially, it produces a strong rotten egg smell, but binding of the molecule to odor receptors prevents them from receiving additional signals.

In the case of this particular chemical, the loss of sensation can be deadly, as it is extremely toxic.

Aroma Compound Uses

Odorants are used to make perfumes, to add odor to toxic odorless compounds (e.g., natural gas), to enhance the flavor of food, and to mask undesirable scents.

From an evolutionary standpoint, scent is involved in mate selection, identifying safe/unsafe food, and forming memories.

According to Yamazaki et al., mammals preferentially select mates with a different major histocompatibility complex (MHC) from their own.

MHC can be detected via scent. Studies in humans support this connection, noting it's also affected by the use of oral contraceptives.

Aroma Compound Safety

Whether an odorant occurs naturally or is produced synthetically, it may be unsafe, especially in high concentrations.

Many fragrances are potent allergens. The chemical composition of fragrances is not regulated the same from one country to another.

In the United States, fragrances in use prior to the Toxic Substances Control Act of 1976 were grandfathered in for use in products.

New aroma molecules are subject to review and testing, under the oversight of the EPA.

Anne Marie Helmenstine, Ph.D.

·   Ph.D. in biomedical sciences from the University of Tennessee at Knoxville - Oak Ridge National Laboratory.

·   Science educator with experience teaching chemistry, biology, astronomy, and physics at the high school, college, and graduate levels.

·   ThoughtCo and About Education chemistry expert since 2001.

·   Widely-published graphic artist, responsible for printable periodic tables and other illustrations used in science.

Experience

Anne Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education since 2001, and other sciences since 2013. She taught chemistry, biology, astronomy, and physics at the high school, college, and graduate levels. She has worked as a research scientist and also abstracting and indexing diverse scientific literature for the Department of Energy.

In addition to her work as a science writer, Dr. Helmenstine currently serves as a scientific consultant, specializing in problems requiring an interdisciplinary approach. Previously, she worked as a research scientist and college professor. 

Education

Dr. Helmenstine holds a Ph.D. in biomedical sciences from the University of Tennessee at Knoxville and a B.A. in physics and mathematics with a minor in chemistry from Hastings College. In her doctoral work, Dr. Helmenstine developed ultra-sensitive chemical detection and medical diagnostic tests.

Anne Marie Helmenstine, Ph.D.

ThoughtCo and Dotdash

ThoughtCo is a premier reference site focusing on expert-created education content. We are one of the top-10 information sites in the world as rated by comScore, a leading Internet measurement company. Every month, more than 13 million readers seek answers to their questions on ThoughtCo.

For more than 20 years, Dotdash brands have been helping people find answers, solve problems, and get inspired. We are one of the top-20 largest content publishers on the Internet according to comScore, and reach more than 30% of the U.S. population monthly. Our brands collectively have won more than 20 industry awards in the last year alone, and recently Dotdash was named Publisher of the Year by Digiday, a leading industry publication.

https://www.thoughtco.com/aroma-compounds-4142268