Analyze This! Environment

Analyze This: Beauty products are big sources of urban air pollution

Home cleaning and other products also turn out to be surprisingly large culprits

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A large percentage of air pollution in cities such as Los Angeles, Calif., may be due to the use of common household products, one study finds. Each use of hairspray, glue and paint, for instance, has a small effect. But when used by millions of people, the effect on air quality can be large.

MattGush/iStockphoto

By Lillian Steenblik Hwang

People commonly use shampoo, hairspray, deodorant, cleaning sprays, paint and glues. Such products can dirty the air. In fact, they are as bad for urban air as is burning gasoline or diesel fuel. That’s the finding of a recent study.

Each use of these products releases a mix of chemicals. Some of these belong to a class known as VOCs. That’s short for volatile organic compounds (which means they are gases and contain carbon). Many VOCs hang around in the outdoor air. Quite a few common VOCs come from products made from petroleum and other fossil fuels.

Certain VOCs can react with other chemicals in the air to create ozone. These VOCs can also help create particles known as “fine” (or small) particulates. Ozone is an ingredient of smog. That smog, along with high levels of fine particulates, can make it hard to breathe. This can be especially true for people who have lung problems, such as asthma. Ozone and particulates also can contribute to other lung problems, diabetes and heart disease.

When people think of outdoor air pollution, their thoughts probably go to the exhaust gases spewed by cars and trucks. Or they might think of gases leaving factory smokestacks. But “sources of air pollution [in cities] are becoming more diverse,” Brian McDonald told Science News. McDonald is a chemist. He works at the Cooperative Institute for Research in Environmental Sciences in Boulder, Colo. He shared his team’s new findings in February at a meeting of the American Association for the Advancement of Science in Austin, Texas.

On average, people use 15 times more gasoline and diesel, by weight, than VOC-emitting household products. But cosmetics, cleansers and other household products created 38 percent of the VOC emissions that this recent study found in city air.

In fact, those products were bigger contributors than fossil fuels were to the creation of fine particulates, ozone and smog. Frequent use of these products by millions of people daily can really add up to a lot of air pollution.
 

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In Los Angeles, consumer goods such as bath products and cleaning chemicals make up a tiny amount of the sources releasing VOCs into the air. They have an enormous effect, however. For instance, they are responsible for as much VOC pollution in cities as is the burning of gasoline and diesel.
Reprinted with permission from B.C. McDonald et al., Science 359: 760 (2018)

Data Dive: 

  1. Examine the data for gasoline presented in both pie charts:
    1. What is the percent (by mass) of gasoline used?
       
    2. What percent (by mass) of the VOCs measured in Los Angeles are from gasoline fuel and exhaust?
       
    3. If the total mass of measured VOC emissions is about 350 gigagrams (385,809 tons), what is the mass of VOC emissions from gasoline and from exhausts emitted by its use?
       
    4. Calculate the approximate percent (by mass) of gasoline VOCs, due to gasoline use and the VOCs released by gasoline and its exhaust in the Los Angeles study. Show your work.
       
  2. Examine the data for consumer and industrial products presented in both pie charts:
    1. What is the percent (by mass) of consumer and industrial products used?
       
    2. What percent of the VOC emissions measured in Los Angeles are from consumer and industrial products?
       
  3. Based on the information in the pie charts, is the percent (by mass) of some class of product a good indicator of how much its use contributes to VOCs in city air? Explain your conclusion.
     
  4. What is a possible reason for why contributions for VOC emissions are higher for consumer products than they are for exhaust from gasoline or diesel fuel burning?
     
  5. Describe how you would represent the data in these pie charts as a bar graph, either with words or by drawing out the graph. Which representation is best suited for these data? Justify your answer.

Beyond the data:

What can you do to reduce pollution from VOC-releasing household products? Are there alternatives that can be used in your home?

 

Analyze This! explores science through data, graphs, visualizations and more. Have a comment or a suggestion for a future post? Send an email to sns@sciencenews.org.

 

Power Words

More About Power Words

American Association for the Advancement of Science (or AAAS)    Formed in 1848, it was the first permanent organization formed to promote the development of science and engineering at the national level and to represent the interests of all its disciplines. It is now the world’s largest such society. Despite its name, membership in it is open to anyone who believes “that science, technology, engineering, and mathematics can help solve many of the challenges the world faces today.” Its members live in 91 nations. Based in Washington, D.C., it publishes a host of peer-reviewed journals — most notably Science.

atmosphere     The envelope of gases surrounding Earth or another planet.

average     (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

chemical     A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

chronic     A condition, such as an illness (or its symptoms, including pain), that lasts for a long time.

compound     (often used as a synonym for chemical) A compound is a substance formed when two or more chemical elements unite (bond) in fixed proportions. For example, water is a compound made of two hydrogen atoms bonded to one oxygen atom. Its chemical symbol is H2O.

data     Facts and/or statistics collected together for analysis but not necessarily organized in a way that gives them meaning. For digital information (the type stored by computers), those data typically are numbers stored in a binary code, portrayed as strings of zeros and ones.

diabetes     A disease where the body either makes too little of the hormone insulin (known as type 1 disease) or ignores the presence of too much insulin when it is present (known as type 2 diabetes).

diesel fuel     Heavier and oilier than gasoline, this is another type of fuel made from crude oil. It’s used to power many engines — not only in cars and trucks but also to power some industrial motors — that don’t rely on spark plugs to ignite the fuel.

environmental science     The study of ecosystems to help identify environmental problems and possible solutions. Environmental science can bring together many fields including physics, chemistry, biology and oceanography to understand how ecosystems function and how humans can coexist with them in harmony. People who work in this field are known as environmental scientists.

evaporate     To turn from liquid into vapor.

exhaust     (in engineering) The gases and fine particles emitted — often at high speed and/or pressure — by combustion (burning) or by the heating of air. Exhaust gases are usually a form of waste.

fossil fuel     Any fuel — such as coal, petroleum (crude oil) or natural gas — that has developed within the Earth over millions of years from the decayed remains of bacteria, plants or animals.

mass     A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.

organic     (in chemistry) An adjective that indicates something is carbon-containing; a term that relates to the chemicals that make up living organisms. (in agriculture) Farm products grown without the use of non-natural and potentially toxic chemicals, such as pesticides.

ozone     A colorless gas that forms high in the atmosphere and at ground level. When it forms at Earth’s surface, ozone is a pollutant that irritates eyes and lungs. It is also a major ingredient of smog.

particulate     A tiny bit of something. A term used by pollution scientists to refer to extremely tiny solid particles and liquid droplets in air that can be inhaled into the lungs. So-called coarse particulates are those with a diameter that is 10 micrometers or smaller. Fine particulates have a diameter no bigger than 2.5 micrometers (or 2,500 nanometers). Ultra-fine particulates tend to have a diameter of 0.1 micrometer (100 nanometers) or less. The smaller the particulate, the more easily it can be inhaled deeply into the lungs. Ultra-fine particulates may be small enough to pass through cell walls and into the blood, where they can then move throughout the body.

petroleum     A thick flammable liquid mixture of hydrocarbons. Petroleum is a fossil fuel mainly found beneath the Earth’s surface. It is the source of the chemicals used to make gasoline, lubricating oils, plastics and many other products.

pollutant     A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.

smog     A kind of pollution that develops when chemicals react in the air. The word comes from a blend of “smoke” and “fog,” and was coined to describe pollution from burning fossil fuels on cold, damp days. Another kind of smog, which usually looks brown, develops when pollutants from cars react with sunlight in the atmosphere on hot days.

urban     Of or related to cities, especially densely populated ones or regions where lots of traffic and industrial activity occurs. The development or buildup of urban areas is a phenomenon known as urbanization.

volatile     Chemical that easily evaporates into the gas phase.

volatile organic compounds (VOCs)     Certain solid and liquid chemicals that evaporate (become gases), often at room temperature or lower. Many of these chemicals can be harmful if inhaled or allowed to move through the skin. Concentrations of these chemicals tend to be higher indoors than out. Sources of VOCs include numerous household products, such as paints, varnishes, waxes, oil-dissolving solvents, cleansers, disinfecting, cosmetics, degreasers and glues. Many fuels also release VOCs.

Citations

Citation:

Journal:  B. McDonald et al. Volatile chemical products emerging as largest petrochemical source of urban organic emissions. Science. Vol. 359, February 16, 2018, p. 760. doi:10.1126/science.aaq0524.

Read more about this story at Science News: Household products make surprisingly large contributions to air pollution

About Lillian Steenblik Hwang

Lillian Steenblik Hwang is the associate digital editor for Science News for Explores. She has a bachelor's degree in biology (and a minor in chemistry) from Georgia State University and a master's degree in in science journalism from Boston University.

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