The Air Inside

Professor Richard Corsi shares why a scented candle could be among the worst things in your home. He and other faculty are quickly being recognized as worldwide indoor air quality experts.

Dr. 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 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.

Graduate student Matt Earnest performs an expiriment at the Center for Energy and Environmental Resources.

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 & 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."

House in which students and faculyt can perform research.

House in which students and faculty can perform research. Click to expand.

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.

At faculty and students' disposal is a three-bedroom, 1,300 sq. ft. 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:

  • 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.


Richard Corsi holds the E.C.H. Bantel Professorship for Professional Practice.

Research Team

Richard Corsi
Dr. Richard Corsi, P.E., ECH Bantel Professor for Professional Practice

Kerry Kinney
Dr. Kerry Kinney, Associate Professor, Roberta Woods Ray Centennial Fellowship in Engineering

Atila Novoselac
Dr. Atila Novoselac, Assistant Professor

Jeffrey Siegel
Dr. Jeffrey Siegel, Associate Professor, J. Neils Thompson Centennial Teaching Fellow in Civil Engineering

Ying Xu
Dr. Ying Xu, Assistant Professor