The University of Texas at Austin
  • The air inside

    By Melissa Mixon, Cockrell School of Engineering
    Published: June 2, 2011
    Richard Corsi has helped build a unique program in the Cockrell School of Engineering that has become recognized as one of the world's top programs in the indoor air quality field.

    Richard Corsi isn’t paranoid when he walks into a room, and he doesn’t want you to be either.

    Still, there are things that grab his attention, starting with the room’s smell. If there’s a strong artificial lemon or pine odor –- the kind that’s most popular in cleaning detergents –- Corsi cringes.

    The smell of a scented candle, burning incense and mothballs elicits another cringe.

    Why? Because Corsi, director of the Cockrell School of Engineering‘s National Science Foundation-funded Indoor Environmental Science and Engineering Program, has spent nearly 20 years of his career researching and teaching about indoor air pollution, its causes and ways to prevent it.

    Over the years, Corsi has helped build a unique program in the Cockrell School of Engineering that has become recognized as one of the world’s top programs in the indoor air quality field. The academic program, which focuses exclusively on indoor environmental science and engineering, is unprecedented in the U.S. as are the laboratory facilities that Cockrell School students in the program use to test their experiments.

    As a testament to the program’s strength, the International Society of Indoor Air Quality and Climate selected Austin as the location for its next triennial conference, and Corsi as president of the conference. The Indoor Air 2011 conference runs June 5-10 and is expected to attract up to 1,200-1,500 of the world’s leading experts in indoor air quality. It will cover everything from endocrine disrupters, a contaminant often found in dust and that can harm reproductive health during fetal and infant exposures, to air quality in airplanes and offices, how the quality of indoor air impacts allergy and asthma sufferers, and new strategies and technologies for improvement of indoor air quality.

    Other countries in Scandinavia and the Pacific Rim spend more money researching and actively improving indoor air quality, and Corsi wants the U.S. to catch up in this field.

    “In the U.S., we spend most of our time thinking about outdoor air pollution but Americans spend 90 percent of their time indoors, that’s over 21 hours a day,” said Corsi, a professor in civil, architectural and environmental engineering. “So if we really want to impact the quality of the air we breathe, we must pay far more attention to pollutants in homes, offices and schools.”

    Clean air: what it does and does not smell like

    An easy place to start is to take a hard look at the pollutants we bring into our homes, like scented candles and house cleaners. The candles give off particulate matter that, depending on the amount inhaled, can affect a person’s heart and lungs, among other things. And many common household cleaners emit toxic pollutants that can cause health risks depending on the frequency and duration of exposure as well as the conditions in the home.

    Matt Earnest
    Graduate student Matt Earnest performs an experiment.

    “We’ve been taught that clean air smells like lemons or pine cleaner, when in fact clean air doesn’t have a smell,” said Matt Earnest, a graduate student in the Environmental and Water Resources Engineering program. “When I’m assessing whether air is clean, I base it on if I can smell it. If I can, I don’t think it’s clean.”

    At the Center for Energy and Environmental Resources at the J.J. Pickle Research Campus, graduate students like Earnest put these household products to the test.

    To do so, graduate students use a large myriad of specially-designed environmental chambers, each of which can be tightly controlled for things like ventilation and humidity to ensure each experiment has the same variables. They even use breathing human simulators (thermal manikins) in room-sized chambers to study human exposures to pollutants and the effectiveness of strategies to reduce those exposures.

    Using fluid mechanics and mass transport, Earnest can study how the toxic chemicals move through the room and what their actual exposure levels to a human would be. Since it began in 2007, Earnest’s research has found that exposure levels in his tests can be up to five times higher than what’s traditionally been predicted with older, less sophisticated models.”

    The long-term goal of his and other students’ work is to get a better picture of exposure levels and, ultimately, to reduce them.

    “Over four million people clean for a living and on average Americans spend 30 minutes per day cleaning,” Earnest said. “So this information would be beneficial for them because it offers little practices that don’t require a lot of know-how and would be easy to implement.”

    Indoor air quality doesn’t just affect physical health. Other research from current and former students includes preliminary study results that indicate performance on standardized tests improves when a school’s air quality is higher. Another graduate student in the program is currently investigating cement replacement materials that can reduce carbon dioxide emissions and energy demand of cement processing, while maintaining structural functionality and a healthy indoor environment.

    House in which students and faculty perform research
    House in which students and faculty perform research.

    At faculty and students’ disposal is a three-bedroom, 1,300-square-foot manufactured home that is fully instrumented and used for a range of research projects. Among the projects being tested are simple, but aesthetically pleasing materials which could be placed in the home –- on ceilings or fan blades –- to cancel out the level of pollutants and chemical byproducts present.

    Research track record

    Research by students and faculty in the Cockrell School’s indoor air quality program has already made a difference in how we respond to chemical attacks.

    After anthrax attacks in 2001 forced closure and decontamination of several large public buildings, including the Hart Senate Building in Washington, D.C., the then-unfamiliar nature of the threat forced quick responses based on little experience and cost hundreds of millions of dollars.

    Soon after, Corsi received a $1.4 million federal contract to study the physical and chemical interactions that occur between four airborne decontaminants (chlorine dioxide, ozone, hydrogen peroxide and methyl bromide) and the surfaces they encounter in buildings. The project was confined to discovering unwanted removal of decontaminants from air to surfaces, and what, if any, byproducts remain behind. Such information allows emergency responders to better determine the best type of decontaminants to apply, at what concentration and for how long.

    “We would hope the product of our research will never have to be used,” Corsi said. “But it will be available, should it ever be needed.”

    Tips to improve indoor air quality in your home

    Undoubtedly, students and faculty have changed their own personal practices based on what they’ve learned while researching indoor air pollutants.

    Earnest doesn’t use air fresheners and only cleans with water and baking soda. Corsi won’t use scented candles or incense. Instead he recommends unscented beeswax or soy candles, if a person is compelled to burn candles at all.

    If you want to improve the quality of the air you breathe indoors, follow these tips from Corsi and his team (PDF):

    • Avoid exposure to formaldehyde. Do not purchase furniture or shelving/cabinetry consisting of pressed-wood products that contain urea-formaldehyde resins. Also, wash permanent press clothing, sheets and other fabrics before using.
    • Make sure that you switch on a bathroom fan or open a window in the bathroom while showering/bathing or using any chemicals to clean in the bathroom.
    • Some laundry bleaches and dishwasher detergents contain chlorine that chemically reacts with soiled clothing or food on dishes and leads to large amounts of chloroform that is released to indoor air. Consider opening a window or vent fan in your laundry room if you use chlorine bleach while doing your laundry. Consider switching on a stove vent in your kitchen while you do your dishwashing. Each will help to direct the chloroform outdoors and reduce its accumulation in the air of your home.
    • Use floor mats at all entries to clean shoes, or better yet have family members and guests take their shoes off before entering your home. Shoes are a primary means of tracking harmful chemicals such as pesticides, other heavy organic chemicals, and heavy metals into homes.
    • Avoid nursery or other extensive home renovations (new carpet, paint, furniture) during pregnancy or for several years after a child is born.
    • Quote 2
      Julia Smith said on Jan. 19, 2012 at 2:14 p.m.
      Especially the part of : “Over four million people clean for a living and on average Americans spend 30 minutes per day cleaning,” must me studied some more is what I think. In Europe a lot of test concerning clear air are done with better results every year. Alsways interesting how others think about this.
    • Quote 2
      Mike Scanlon said on Dec. 19, 2011 at 11:06 p.m.
      Interesting article and good tips. Thanks. You mentioned air fresheners. I think air fresheners are one of the worst offenders of indoor air quality. I've read quite a few articles from reliable sources on the pollutants, the toxic chemicals and carcinogens in many of them, and these pollutants are being released continuously. Some air fresheners are actually designed to deaden our sense of smell. Scary stuff.
    • Quote 2
      Nadav said on Sept. 29, 2011 at 3:45 a.m.
      Finally, someone who says that this whole industry is made of poison. I personally can't stand these smells, and I'm glad to see more people agree with me. Nadav
    • Quote 2
      Rich Corsi said on June 21, 2011 at 12:26 p.m.
      Response to Janet: I preface these comments with the caveat that our research team at UT has not worked on this topic. My comments are based on past reading of the technical literature (what others have done). UV systems in HVAC ducts can be (not necessarily are) problematic or ineffective for three reasons. First, for airborne microorganisms the residence (exposure) time in the zone where the UV light is activated is often too short for effective microbial "kill". As such, UV systems are best used to try to affect microorganisms that deposit or grow on surfaces. Microorganisms (mold spores, bacteria) can collect on HVAC filters (I have seen sunstantial growth on filters in Texas schools). Past work has shown that the effectiveness of UV on filters is complicated (second reason) due to "shielding" of the UV light by other particles that collect on teh filters. In commercial buildings it is not uncommon to have substantial condensation imemdiately downstream of cooling coils and this can lead to microbial growth on duct walls. This might be a region where UV light could be effective, but I am not aware of any specific research on this issue. The final reason for concern about UV systems is that if not designed correctly (most should be), UV can lead to the formation of ozone, which is never a good thing to form indoors. Ozone itself is a very harmful air pollutant, but it also reacts to form equally harmful pollutants indoors. I will need to get back to question 2. The answer to quesiotn 3 is "no". We had thought about this at one time, but simply do not have the time or resources to do so (although I believe it could be a great resource).
    • Quote 2
      Rich Corsi said on June 18, 2011 at 10:49 p.m.
      Response to comments on perfumes: Most of the scenting agents used in perfumes and other fragrances are benign to most (not all) people. Some people do have intolerances to certain components of fragrances, although the specific mechanisms of intolerances or chemnical mixtures are not well understood (a lot more research is needed on this topic). However, most common scenting agents are easily and rapidly oxidized (transformed) by ozone, which always exists at measurable quantities indoors with highest levels when outdoor ozone is elevated or when an indoor ozone source is used (laser printer, photocopy machine, ion generator, in-duct electrostatic precipitator). When ozone reacts with common scenting agents (mostly terpenes and terpene alcohols)a wide range of (known) harmful and suspected chemicals (by-products) are formed (we have quantified many at UT). These range in severity from upper-respiratory irritants to carcinogens. There is now ample published literature on this topic, including some very important studies completed at UT. The best SOLUTION to this problem is to avoid sources of ozone indoors and to avoid major sources of scenting agents (and especially avoid the presence of both together!).
    • Quote 2
      Rich Corsi said on June 18, 2011 at 10:41 p.m.
      Response to Geoffrey Van Olden: This is an understandable response. Solutions are often complicated to describe and do not make for good sound bites or short stories. But I disagree with the premise that identification of problems is not part of a solution. There are three ways to solve indoor air quality problems. These include (1) reduction, removal or avoidance of sources, (2) proper ventilation, and (3) air purification, with a preferred order as listed. The first (and most important) solution of source reduction is impossible to address unless one has a basis for understanding specific sources, what and how much they emit. Our team at UT engages in a great deal of source characterization and we report on indoor sources that emit a lot of harmful pollutants, as well as sources that are relatively safe. Since the federal government and most states (except for California) do not ban much of anything for indoor use, it is important that sources (or as you say "problems") be properly characterized and prioritized so that the public can make its own decisions on whether to avoid them. For example, not purchasing moth repellents is a great solution to being exposed to very high levels of chemicals that lead to greater environmental cancer risks than any other synthetic chemical that has been studied. Here, knowledge of the problem leads to a great and easy solution. The second solution (proper ventilation) is also very important. Unfortunately, our country is going in the opposite direction (less ventilation) in the name of energy conservation. Researchers at UT have been studying the effects of reduced ventilation on indoor air quality, chemical reactions in buildings, and occupant exposures to pollutants of indoor and outdoor origin. In doing so our goal is to find ways to ventilate in an effective manner that both reduces energy costs while not degrading, and in some cases improving, indoor air quality. If source control and proper ventilation do not work, the use of engineered air purifiers can reduce pollutant levels indoors. My own team in in the forefront of studying new indoor materials that can remove pollutants from indoor air passively (without an energy penalty), and my colleagues have been testing comemrcial air purifiers for their effectiveness and also for optimal placement to reduce occupant exposures to pollution. So, we are very much addressing solutions on all three of the major solution fronts. I have also developed a short document on easy ways to improve indoor air quality in homes and would be happy to send it to anyone who wants a copy.
    • Quote 2
      Rich Corsi said on June 18, 2011 at 10:25 p.m.
      Response to Diane: We have not studied indoor pesticides. However, past research indicates that indoor pesticides do not easily breakdown as they would outdoors and can persist for years after application. A classic study on this subject was done b yteh Southwest Research Institute in San Antonio that found detectable levels of DDT in carpet in 25% of midwestern homes over 20 years after teh use of DDT was banned. Importantly, indoor pesticides can migrate from their location of application to carpet and other flooring materials, and thus are relevant in terms of exposure to infants through inhalation, hand to mouth exposure, and dermal uptake. Pesticides serve an important purpose, but parents of small children should take great care to avoid infant or fetal exposures to pesticides (reasons far too numerous to describe here).
    • Quote 2
      Allison said on June 13, 2011 at 1:31 p.m.
      This is amazing information that EVERYONE should be privy to. I give workshops on this for a living, trying to help moms understand the implications of using toxic cleaning products and renovating with toxic building materials, especially while pregnant, nursing or with small children. We think the smells of harsh chemicals (pine, lavender, lemon) are "clean" but the single word "FRAGRANCE" can contain thousands of chemicals, none of which have to be disclosed due to trade secret laws. Thank you for sharing this information in a loving, yet fact-based, manner.
    • Quote 2
      Nick said on June 13, 2011 at 6:18 a.m.
      I agree with the comment above about perfumes. There have been other articles published recently showing that some very popular scents have up to 20 different chemicals in them, many of which are known carcinogens. It should be required for makers to disclose exactly what's in some of these things.
    • Quote 2
      Geoffrey Van Olden said on June 10, 2011 at 10:21 p.m.
      I read about alot of problems and not many solutions.
    • Quote 2
      The Weekly Web Wonk, v6.10.11 | GNI Strategies said on June 10, 2011 at 5:16 p.m.
      [...] Attn: Desk Jockeys — Is your office’s air safe to breathe? This UT prof is on the case. [...]
    • Quote 2
      Diane said on June 10, 2011 at 7:44 a.m.
      What are your results on using exterminators and indoor pesticides?
    • Quote 2
      Kevin said on June 9, 2011 at 12:12 p.m.
      'Use floor mats at all entries to clean shoes, or better yet have family members and guests take their shoes off before entering your home. Shoes are a primary means of tracking harmful chemicals such as pesticides, other heavy organic chemicals, and heavy metals into homes.' I've never understood this Western culture of wearing your dirty, filthy outside shoes inside your house (on your furniture, in bed even). It makes no sense whatsoever, any way you look at it. What is this irrational phobia of feet/socks/house slippers? Thanks for confirming the simple lack of hygiene in this practice.
    • Quote 2
      Rachel said on June 9, 2011 at 10:39 a.m.
      Agreed. I have complained repeatedly about the "air freshener" installed a year ago in our office restrooms, but to no avail. I would love to have a readily available test for home or office use to determine air quality levels. This stuff is poison, not perfume!
    • Quote 2
      Bear Poth said on June 9, 2011 at 9:35 a.m.
      It's nice to see the value of research that the Cockrell School is doing. This is an important and overlooked area of research. Most people are focused on the outdoor side of this issue. The research unding and conferences also have a positive impact on Texas' economy. Thanks for the article.
    • Quote 2
      Bob Shary said on June 9, 2011 at 8:51 a.m.
      What about massive amounts of hairspray used in the bathroom etc. Especially aggravating to me is the aersol type! This has to have a dilaterious effect.
    • Quote 2
      Rick Perkins said on June 9, 2011 at 8:48 a.m.
      Many engineers / scientists who have worked on NASA Manned Space Programs have had to deal with Indoor Air issues for decades. Plastic materials, while often given a bad wrap in the press, can be selected based on Volatile Condensible Material properties that do not "off gas" plasticizers or unreacted monomers. If you can imagine living in the Space Station where there is no "fresh air", you can appreciate the need for using materials that have absolutely no off-gassed products. Be aware of biodegrading products and animals that exude methane. Dr. Corsi is doing good to help bring this type of knowledge to our everyday living spaces.
    • Quote 2
      Jane said on June 9, 2011 at 8:27 a.m.
      Will this research lead to any changes here on the UT campus? I'm thinking particularly of all the chemicals that are used on a daily basis to keep the buildings "clean".
    • Quote 2
      Richard Franks said on June 9, 2011 at 7:50 a.m.
      I was told the worst IAQ offender is a new plastic shower curtain. The chemicals sprayed on the curtain to inhibit mold and to retain it's pliability combine with the steam from the shower to create a toxic fog. Since you are in a small confined area during your shower, you would be fully surrounded by the 'fog' and the steam droplets help carry the toxins deep into your lungs. Any truth to this ??
    • Quote 2
      Alma said on June 8, 2011 at 10:22 a.m.
      I've often wondered about perfume/cologne. It's so offensive to me that I tell folks I have an allergy. This keeps them out of my office/car, but it doesn't help with strangers in the elevator, where I just hold my breath. Appreciate the insight...
    • Quote 2
      Janet Swaffar said on June 8, 2011 at 9:28 a.m.
      Question #1: What do you think about UV lights in AC and heater units? A UV light--can it address mold and allergen build-up in air ducts? Many on the market and prices range from under $100 to thousands. Claims for effectiveness commensurate. Question #2: We use minimal AC (on at 80 degrees in late afternoons and early evenings to cool down house) and keep our windows open. Live in residential area with bamboo and trees around house. How would you compare potential air quality of closed environment to such an open one? Question #3: Do you have a Q & A website? Or other public access sites? As these answers may be off topic, feel free not to post but would appreciate answers very much.
    • Quote 2
      Evelyn said on June 6, 2011 at 6:31 p.m.
      Glad to read this story, since advertising has convinced people they need these artificial scents and chemical cleansers. Sometime I'll be removing carpet in my home and replacing it with...? bamboo? NVOC carpeting? That change is in the future so there's time to look into options.
    • Quote 2
      Barbara Carlson said on June 6, 2011 at 3:49 p.m.
      Thank you for making all of this explicit. Many of us who detest scented candles, incense, etc. are ridiculed by people who love the scents, and cannot understand why those "fragrances" give us a huge headache.
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