Brett Singer, PhD Group Leader – Indoor Environment Division Lawrence Berkeley National Laboratory (LBNL) – Original Air Date: 5-6-2016| Episode: 413

Air Date: 2-1-2019|Episode 532

Today we flash back to a great Research to Practice show with Brett C. Singer, PhD. Dr. Singer is the Staff Scientist and Group Leader of Indoor Environment in the Energy Analysis and Environmental Impacts Division of Lawrence Berkeley National Laboratory (LBNL). He is also a Principal Investigator in the Whole Building Systems Group in the Building Technologies and Urban Systems Division. Dr. Singer conceives and leads research projects related to air pollutant emissions and physical-chemical processes, and pollutant exposures in both outdoor and indoor environments, aiming to understand real world processes and systems that affect air pollutant exposures.

The recent focus of Dr. Singer’s work has been indoor environmental quality and risk reduction in high performance homes, with the goal of accelerating adoption of IAQ, comfort, durability and sustainability measures into new homes and retrofits of existing homes. Key focus areas of this work are low-energy systems for filtration, smart ventilation and mitigation approaches to indoor pollutant sources including cooking. Dr. Singer co-developed the Population Impact Assessment Modeling Framework (PIAMF). He holds a PhD in Civil & Environmental Engineering from the University of California, Berkeley.

Original Video

Z-Man’s Blog:

Build tighter and ventilate righter

The personal experience of riding a bicycle home from the campus of Temple University through heavy traffic piqued Brett Singer’s interest in air quality. He went on to study the effect of motor vehicle emissions as a graduate student at the University of California at Berkeley, then moved indoors to study second hand tobacco smoke as a post-doctoral researcher at Lawrence Berkeley National Lab (LBNL). Today Dr. Singer is Leader of the Indoor Environment Group and a Staff Scientist in the Whole Building Systems Department at LBNL.

Nuggets mined from today’s’ episode:

Much of what we know about the health effects of air pollutants and particles comes from studies of outdoor air pollution. That research was made possible by data from the outdoor monitoring network that EPA helped to create. EPA created the criteria for outdoor air monitoring which is done by states and at the local level.

Particulate matter or “PM” is a mixture that includes particles of varying sizes and chemical composition. Many particles indoors come from outdoors but the overall mixture of indoor particles can be different from the mixture outdoors. This is because there are indoor emissions of particles and differences between the indoor and outdoor environments change the mixture over time. Particles may have both liquid and solid components. Extreme changes in RH and temperature can change particles. The chemistry of indoor particles is another field of study. The building envelope removes some particles. The better we understand particles, the better we can remove them.

We have opportunities to control PM concentrations indoors. Air sealing can keep PM outdoors. CO is nonreactive indoors, while ozone is reactive. PM indoors deposits on material. PM 2.5 is more hazardous for people with compromised respiratory or cardiovascular health, including people with COPD and asthma

IAQ is often a challenge in residences of those in low socioeconomic status (SES). Other environmental quality characteristics – like comfort and natural light – can also be a problem in low-SES. With little or no money to spare on improving IAQ source control is the primary strategy.

Tips: don’t burn indoors and ventilate. In cases of asthma or other cardio respiratory problems seek available resources to get the needed help.

When tightening homes we need to be more attentive to PM indoors.

Tips for controlling PM indoors:

Cooking produces particles. Cooking with oils also creates acrolein an irritant.

Range hood should vent to the outside or else open the kitchen window. Turn on range hood a few minutes before you light the burner and allow it to run a few minutes after cooking is completed.

Cook on back burner.

Dr. Singer recognizes that the most important research to a practitioner is that which will help the clients.

Great information resources are available. We publish and get peer review in an attempt to produce accurate information. Information published in peer-reviewed journals is generally more reliable; but even published papers should be read critically. If you can’t find the answers to your IEQ questions call potential resources such as the EPA’s indoor environmental division, California Air Resource Board, etc.

Not all industry sponsored research is biased.

Obtaining the answer to a relatively simple question is often not so simple. Rather than focus on the cost, focus on the importance of proper controls and isolating the factor that you want to study. It is true that it often costs more than one might think; but that is because it is often more complicated to do the experiment or study correctly than one might think from a relatively simple question.

For example: formaldehyde is known to be a respiratory irritant and a carcinogen. A study to answer the question: “do homes constructed with lower emission materials have lower formaldehyde emissions after constructions?” Must rule out or discount other contributive causes: such as: suitability of housing stock studied, new homes have higher emissions, age of homes, season during which study is performed, temperature, RH, air exchange rates, etc. The study found (42% adjusted and 27% unadjusted) lower formaldehyde levels in homes built with low emission materials.

LBNL’s Residential Building Systems Group tries to focus its studies on research to move the industry forward 5-10 years in the future. They have a big eye on practice, improving IEQ in real buildings. Great homes that are comfortable, durable, and provide good indoor air quality, while also using very little energy.

Some noteworthy LBNL studies of special interest to IEQ investigators and remediators include: radon control, second hand smoke, 3rd hand smoke (chemicals from smoking stick around and are transported), the health and productivity benefits of good indoor air quality, and synergistic approaches to improving both IEQ and energy efficiency when doing residential retrofits.

Brett recognized the importance and value of groups and associations such as: IAQA, AIHA. ASHRAE, etc. The groups are great reservoirs of information. This is where the pros go to learn how to help their clients.  Impressed by his colleagues who are trying to contribute to making a positive difference and provide useful info for the world.

His message to homeowners, if your contractor doesn’t know or is unconcerned about IEQ and energy efficiency find another contractor!

Most research on health effects of particles are based on studies looking at higher levels outdoors. Much less research has been done to specifically quantify the hazards of indoor generated particles, including those from burning candles or incense. We do know that other particles of the same size are harmful; unless and until we find that particles from indoor sources are not hazardous, we should assume candle and incense particles are hazardous as well. Use an air filtration device when burning candles or incense.

2nd and 3rd hand smoke is created during both cigarette and marijuana smoking.

Burning natural gas creates ultrafine particles.

General caution against the use of chemical air cleaners: ozone, hydroxyls. Be skeptical. Ask about the hazards? How can we tell they are working? What happens if they are not working perfectly.

Retrofitting is an opportunity to improve IEQ and energy efficiency not make it worse.


General Resources:

EPA Indoor Environments Division:

Building America Solutions Center:

Build America Program


Specific Resources:

When air sealing tightly use the ASHRAE ventilation standard.

The public should know that there are caring and committed people in government at the federal, state and local level who are working for them.