HOMEChem Open House – House Observations of Microbial and Environmental Chemistry

Air Date: 6-22-2018|Episode 508

Z-Man’s Blog:

Learning more in a month than was learned over decades HOMEChem, or House Observations of Microbial and Environmental Chemistry

The HOMEChem experiment is centered around three science questions:

• What are the sources of chemical oxidants in the indoor environment, and how are they impacted by changes in light conditions and human activities? Examples of chemical oxidants are hydroxyl radicals (OH), nitrate radicals (NO3-), and ozone (O3), which are very reactive.
• What are the main sources of organic compounds in the indoor environment? How does the physical and chemical transformation of organic compounds from gaseous state into particulate phase (also known as “secondary organic aerosol”) and other chemical compounds present in minute amounts (also known as trace gas species) change in response to human activities?
• What are the sources of indoor reactive nitrogen species, and to what extent is their presence indoors influenced by outdoor pollution?

Atila Novoselac, PhD

• University of Texas, Austin is using a manufactured house outfitted with 4.5 million dollars of highly sophisticated test instrumentation for IAQ and home performance research.
• It is a 3 bedroom house, with crawl space and small attic. The crawl space is vented. The attic has normal ventilation.
• House has been tested for tightness with blower door and tracer gas. The findings are that the air tightness of the house is slightly better than the typical home.
• The house is currently 11 years old. Painting imperfections exist. In one of the previous projects passive removal paint was used. This paint have been removed, and currently the house has typical interior latex based paint.
• During the HOMEChem experiments, the fan in the air handing unit is ON all the time (and not controlled by thermostat) to provide good air mixing in the house needed to avoid room-to-room variation in measurements.
• Little outside air enters the home through the building envelope due to slight positive pressure within. [Outside air comes into the house dominantly via the well-controlled HVAC system, which operates at ~0.6 – 0.8 air changes per hour].
• The house is fitted with 3 HVAC systems. One overhead air system, one underfloor air system, and a ductless chilled water system. For HOMEChem experiments, only the overhead ventilation system is used as it is the most common in US homes; also, it provides better interior air mixing needed for spatial independent measurements.
• Filtration is not a research focus, and only a coarse air filter is used for the outside air.
• Even though many building operation variables are constrained to secure the quality of comparative measurements, most of the experiments mimic a typical North American home.

Delphine Kasimira Farmer, PhD

• Her prior research experience was focused on what’s going on outdoors.
• Now she’s studying what’s going on indoors. She’s learned that there are many more molecules inside than outside. She has worked in Mexico City known for its high outdoor pollution levels.
• She now sees everything that the sensitive instruments in the test home detect. Seeing huge numbers in the peaks of molecules (organic carbon) across wide spectrum. To her, the diversity of the molecules is more interesting than the concentrations.
• Outdoors sulfate aerosols from power plants and diesel engines are found more outdoors than indoors.
• Many experiments in the home are based on short term spurts of occupancy and activity: mopping floors (10 minutes), cooking (the time it takes to prepare, cook and eat the meal).
• On layer days the house is occupied with activity occurring from 8 AM-6 PM.
• When the house isn’t occupied, everything indoors resets and re-equilibrates.
• At the forefront of her mind are, small molecules which are difficult to manage and detected by multiple highly sensitive spectrometers. Katmandu is known to have both severe outdoor and indoor pollution, attributed in part to dirty cooking over indoor fires. Surprisingly, levels were higher at HOMEChem while a turkey was cooked indoors.
• Has not found dangerous CO levels in the test house. Observing the CO₂ levels during occupancy has been interesting.
• The home provides good opportunity to compare low cost monitors to the highly sophisticated analytical instruments being used. Using low cost monitors in the kitchen and living room.
• Committed to open access to research. Science must communicate.

Marina Vance, PhD

• Environmental engineer assessing exposure levels in real world scenarios in real time by conducting nanoparticle aerosol research.
• Different categories of occupancy and activity occur in the home. Activities are performed by volunteers. Cooking has commonality with the North American diet: typical breakfasts and then for lunch and dinner: stir fry, chili, or lasagna.
• During mopping of floors mass transfer from liquid to gas phase. Cleaning products being used include: pinene based, chlorine based and “green/organic” based.
• For VOC monitoring, volunteers are scheduled to use three categories of consumer products for their personal care: (1) green/organic products, (2) to wear what they usually wear, and (3) highly fragranced products. Both chemical species and concentrations are monitored.
• The role of surfaces (such as walls and furniture) on air phase experiments.
• Huge quantities of ultrafine particles are generated during cooking, especially on gas stoves. These particles grow larger over time.
• A vent hood is present in the kitchen which intentionally isn’t being used.
• Some new instruments and technologies are being used for the first time in the home. A large mass spectrometer looks at molecules in particles. When turkey oils and other particles show up in the air, what about the other molecules that come along for the ride?
• Sloan foundation research into the microbial community has found vast array of bacteria and viruses on surfaces and in the air. What else are the microbes doing and how are they impacting the chemistry? Swab samples are being taken to study both the microbes, their metabolites and chemicals in the home.
• We shed skin flakes and bacteria wherever we go. This bacteria and shed skin glows under UV light. We are all the cartoon character Pigpen.
• Communicating science is the complicated part of the mission. Its important to better communicate the science and make the research actionable.

Richard L. Corsi, PhD

• Sophisticated instruments permit measuring more and closer than ever before.
• Things have been noticed and not understood. IAQ investigators will be able to learn from this research in indoor chemistry.
• Levels of 7,000-8,000 PPM of CO² aren’t uncommon when entertaining at home. Levels go even higher when cooking. These levels of CO₂ would need to be scrubbed on submarines.
• Things have been noticed and not understood. IAQ investigators will be able to learn from this research in indoor chemistry.
• The jury is still out on CO₂. While we need more CO₂ research, we also need to study other chemicals that increase in concentration with occupancy.
• Data suggests that vent hoods are necessary. High oxides of nitrogen are created by cooking.
• Hopes that the research will be able to change the building code to make vent hoods, and improved ventilation/exhaust mandatory and/or retrofitting when homes are sold.
• Research means nothing unless its communicated and utilized. It’s incumbent on researchers to translate information to the front lines. Researchers should be forced to communicate. It should be mandatory that every research article include the practical meaning of the research.
• Opines the research at the test home will result in an important list of 10 things for practitioners to know and do in bullet form.

Corbett and Grace Lunsford

• IAQ and home performance is about control.
• Learning more in one month, than has been learned over decades.
• Everyone who works on a home is affecting IAQ whether they know it or not.
• Telling the story: the skeptic, the mechanic, the traveler, the frontiersman, and the toolmaker.
• Grace is telling Corbett’s story.
• Having babies made Grace more concerned about IAQ.
• We need to change the lexicon, what are we breathing.
• Houses should be built like cars.

Z-Man signing off

Trivia Question:

When the University of Texas at Austin first started, how many professors were there?

Trivia Answer:

Eight