Green Building Research Lab News

Lab news can now be found at twitter, under @etgall for more frequent updates. 


March 8th, 2018

Congrats to the team PTR Pit Crew for their tenacity and dedication to air quality research in the community! Today, the team successfully deployed the GBRLs PTR-TOF-MS to a local middle school where we will measure urban VOCs focusing on emissions from I-5 near the school. The move was a logistical challenge and the group handled it with aplomb. 

Special thanks to Aurelie and Elena for their subsequent dedication to getting the PTR-TOF-MS, endearingly named "Dennis" after this move, up and running after we disturbed it from it's happy humming in the safe confines of the lab....

March 1st, 2018

GBRL Researchers learned today that three conference papers submitted by the team were accepted for podium or poster presentations at the upcoming international conference Indoor Air 2018! Congratulations to student researchers Pradeep R., Elena C.A., David P., and former undergraduate researcher Kyle C. 

The three papers accepted were: 

"Ozone chemistry of building enclosure insulation materials" by Elliott Gall, Donghyun Rim, and Elena Christopher-Allen

"Impact of indoor surface mass accretion on heterogeneous ozone chemistry" by Kyle Chin, David Pleshakov, Brent Stephens, and Elliott Gall

"Impact of green roof surfaces on O3 levels near building ventilation supply" by Pradeep Ramasubramanian, David Pleshakov, Samuel Salin, and Elliott Gall.

Looking forward to Philadelphia this summer and presenting the work and seeing all the great research folks in the ISIAQ community have been up to. 

A fourth abstract was submitted by Myiesha E. to the Mcnair Undergraduate Research conference which will be held in Seattle this summer. Congrats on acceptance of this important work titled "Lab testing of a field-deployable chamber for measuring air pollution fluxes on green roofs."

February 15th, 2018

GBRL Reseacher Naveen W. and Dr. Gall visited Ankeny Row to install energy and air quality monitoring equipment at the Net Zero Energy Pocket Community, Ankeny Row. Find out more here:

A photo from the installation is below:



January 20th, 2018

A new publication of GBRL research, led by colleague Donghyun Rim at PSU-East (aka Penn State) has been published in Building and Envioronment. Congrats to Donghyun on this excellent paper which describes how human surfaces impact indoor ozone dynamics. The paper uses a combination of chemical modeling and CFD to show how reactions at human surface may impact both room levels, but importantly, presonal breathing zone levels of ozone and ozone reaction byproducts under a range of ventilation scenarios. Great images showing the process from CFD: 

January 20th, 2018

Two new projects were recently awarded to the GBRL. In one project, Dr. Gall and researchers at the GBRL will partner with a local company as part of an NSF SBIR award to test a proprietary additive to indoor architectural coatings that may result in degradation of indoor volatile organic compounds through oxidation processes induced by agents present in their coating. The team will use the GBRL's PTR-TOF-MS to understand degradation mechanisms and to observe whether degradation is complete or if any partial degradation products remain. 

In the second project, ASHRAE awarded an Undergraduate Research Equipment grant that Dr. Gall will use to oversee a capstone project for the PSU MME program in the 2018-2019 academic year. This project, titled "Visualizing the Invisible: A Microcontroller-based Indoor Air Quality Teaching Laboratory" will support students as they endeavor to use low-cost micrcontrollers, sensors, and actuators to build workind demonstrations for teaching and outreach related to indoor air quality and building science. 

January 15th, 2018

Dr. Gall and colleagues at PSU, Linda George and Raul Cal were awarded a project from Portland Public Schools to monitor air quality conditions at the Harriet Tubman Middle School site. This 18-month project will include intensive indoor and outdoor air quality monitoring, constuction of scale models for wind tunnel tests to describe site fluid mechanics, and recommendations for renovations to improve student health in and around the buliding. 


December 4th, 2017

Very pleased to announce that a recent research paper, conducted by former Ph.D. student ('17) Omed Abbass in the GBRL, was selected as one of the three Best Papers of 2017 in the journal Building and Environment. This prestigious award was granted to only 3 out of 2000 submissions to the journal. Quite an accomplishment! Many congratulations to Omed Abbass and Dave Sailor, former GBRL Director and now faculty member at Arizona State University on the award. This paper took an in-depth look at the topic of how indoor plants affect indoor air quality. This idea is often promoted, but there is surprisingly little robust research on the topic. This paper is a great start in "clearing the air" as to the facts and fictions of using indoor plants as air cleaners. Further evidence of the importance of this paper is that it was also recently listed as one of the "most downloaded" papers in the journal Building and Environment!

November 29, 2017

Assistant Prof. Elliott Gall had the opportunity to meet with homeowners at the Ankeny Row Net-Zero Energy Pocket in Portland, OR this evening. Dr. Gall is pursuing the creation of an energy/IAQ monitoring test-bed in this pocket of 6 energy-positive homes. This work is in partnership with the local design/build firm, GreenHammer, who oversaw the design, construction, and continued maintenance of these cutting edge homes. The presentation was well-received and we hope to deploy monitoring equipment in early 2018! 

September 30, 2017

GBRL graduate student researcher Pradeep R. and other members of the NSF ecoroof project team are wrapping up our summer field campaign atop of a ecoroof in Portland, OR. For this summer's field campaign, we were able to deploy two sonic anenometers and ozone monitoring equipment. With this data, we will be able to characterize rooftop fluid dynamics and ozone surface fluxes to a real, functioning ecoroof. Now that the rainy  season is here, we will begin processing this data and working with our models. Congrats on a successful first summer deployment - with our lessons learned from this summer we'll be ready for a more intensive campaign in the Summer of 2018!

September 1, 2017

GBRL undergraduate student researcher Ashley Kunesh completed her Research Experience for Undergraduate appointment, and presented her results at the PSU CCAR REU Student Symposium. Ashley's excellent work investigated three research questions that related to VOC dynamics on ecoroofs, or building rooftops covered with vegetation. Ashley's work specifically investigated the substrate (or engineered soil typically used on building rooftops) and employed the GBRL's proton transfer reaction - time of flight - mass spectrometer to measure fluxes of VOCs from ecoroof substrate. Her hypotheses centered around whether the substrate, and the associated microbiological community, would emit meaningful amounts of VOCs that could affect the quality of air entering buildings or urban air chemistry. She investigated these fluxes of substrate VOCs as a function of substrate water content and temperature. Check out a picture below of her custom experimental chamber used to measure substrate temperature, water content, and VOC fluxes. Stay tuned for more as we process the data and continue this line of experimental inquiry! 

August 11, 2017

GBRL undergraduate student researcher Kyle Chin completed his Research Experience for Undergraduate appointment, and presented his excellent work at the PSU CEMN REU Student Syposium. His presentation, titled  "Ozone interaction with building insulation materials" summarizes his work this summer studying the interactions of the air pollutant ozone with building envelope materials. This phenomena is important, as most residential buildings are ventilated with outdoor air only via transport across the building envelope to the indoor space. Kyle's investigation will help shed light on whether the interactions that occur with ozone and building envelope materials are protective (by reducing ozone concentrations entering the building through chemical reactions), harmful (if materials or reactions emit harmful VOCs) or possibly some combination of the two. 

Kyle measured primary VOC emissions, ozone deposition velcoities, and secondary VOC emissions from eight different types of building materials (pictured below).

This work will continue in the lab, and stay tuned for forthcoming results in conference and journal proceedings in 2018! Great job, Kyle!

May 2, 2017

Students in Dr. Gall's Indoor Environmental Quality course embark today on their hands-on Arduino project: CO2 in indoor environments: From sensing to application. This course module, developed in collaboration with the BUILT Lab at PSU will address the role of sensors in "smart" building applications, with a focus on hands-on learning using the Arduino platform. Students will build and program several circuits, culminating in a usable CO2 sensor that can be programmed to act as a input to other circuit components (e.g., as in a demand-controlled ventilation system). See an example video of an project outcome below:

Students will also use off the shelf CO2 sensors in a variety of field studies, including measuring air exchange rates, CO2 exposures, and quantifying likelihood of disease transmission indoors.


May 1, 2017

GBRL Director Elliott Gall was the most cited reseacher in the MME department on the website ResearchGate for the month of April. 

April 15, 2017


Experimental apparatus used to test ozone removal to common indoor plants.

GBRL Research, led by Ph.D. Candidate Omed Abbass has been recently published in the journal Building and Environment. The article addresses the ability of five common types of indoor houseplants to remove ozone. There is a substantial body of work regarding the interaction of outdoor plants and ozone, however, very little generalized data describing the rate of reaction of ozone with typical indoor houseplants is present in the literature. Importantly, this limits our ability to develop mass-balance models of houseplants interactions with ozone in a typical indoor space. This work conducted chamber studies to estimate deposition velocities of ozone to five houseplants which were then used in a time-averaged mass-balance model to determine the extent of removal of ozone (essentially modeling plants as effectiveness as an "air cleaner"). Results indicate that, due to low surface area of plants in a typical indoor space, ozone removal was modest at best, ranging from generally less than 1% to a maximum of 10% with high loading rates. 

More information can be found at the journal homepage:

April 4, 2017

GBRL collaborative research, led by Dr. Donghyun Rim of the "other" PSU (Penn state) has been recently published in the journal Building and Environment. This paper investigated several metrics of particulate matter pollution in four nurseries in Seoul, South Korea. The research used several state of the art tools to investigate a broad spectrum of metrics of PM, including lung deposited surface area and ultra-fine particles. Results indicate that urban nurseries, especially when naturally ventilated, contribute substantially to young children's exposure to harmful PM pollution. Recommendations include careful consideration of ventilation mode, siting of nurseries, and consideration of stand-alone PM filtration in naturally ventilated nurseries. 

More information can be found at the journal homepage:

March 8, 2017

The GBRL was pleased to host visitors from the NCState EcoVillage.  This great group of students visited the GBRL as part of a visit to Portland, OR to broaden prespectives about how cities and Universities are contributing to the sustainability of urban and built environments. The GBRL hosted a group of approximately 15 students in the laboratory at PSU's Engineering Building, providing an overview of ongoing and future research. Student researchers prepared a number of demonstrations to illustrate the connections between fundametnal research and urban sustainability.  Check out photos of the event below:

Assistant Professor and GBRL Director Elliott Gall explains the working principle of the PTR-TOF-MS and ongoing projects measuring VOCs in indoor and urban environments. 

Student researchers Craig Lardiere, Mimi Shand, and Samuel Salin explain the role of low-cost sensors in indoor and urban air quality monitoring, and their progress in creating low cost sensors on the Arduino platlform. 

Mimi Shang and Samuel Salin demonstrate a prototype monitoring platform currently being tested on a breadboard. 

Feb 1, 2017

Congratulations to colleague Toby Cheung for first-authorship on the recent article: Longitudinal assessment of thermal and perceived air quality acceptability in relation to temperature, humidity, and CO2 exposure in Singapore. This work was recently published in Building and Environment, and stems from work that Elliott Gall contributed to during his time as a postdoctoral researcher at the Singapore-Berkeley Building Efficiency and Sustainability in the Tropics program. This work presents an in-depth statistical analysis of longitudinal data describing occupant perceptions of comfort and satisfiaction with indoor air quality. The team applied a range of models, including a machine-learning approach, gaussian process regression, to ascertain whether such data may be predictive of satisfaction at the collective and individual level. 

The article can be accessed via Science Direct.

January 23, 2017

The GBRL recently hosted a group of prospective undergraduate engineering students who were interested in learning more about thermal fluid science research at Portland State University. The students toured the Green Building Research Lab and saw demos about ongoing research on pollutant deposition on building material surfaces, volatile organic compound analysis with PTR-TOF-MS, how to measure turbulent flows, and our team's progress in building Arduino-based air quality sensors. Thanks to the great undergraduate and graduate students in the GBRL who made this tour happen. A few pictures from the event are below:


Pradeep R., graduate student in the GBRL discusses the operation of a sonic anemometer - soon to be deployed to an ecoroof field site.


GBRL Undergraduate researcher, Craig L., discusses the role of Arduino in building science and air quality


Mimi S., undergraduate researcher in the GBRL, shows a prospective student progress on her 'low-ish cost' Arduino air quality sensor. These sensors will soon be field calibrated and deployed at a field site with a vegetated ecoroof to understand spatial variability in air pollution levels across a rooftop. 


December 12th, 2016

The GBRL has received delivery of a proton transfer reaction-time of flight-mass spectrometer! This is a state of the art instrument for measuring volatile organic compounds in real-time and at as low as parts per trillion levels. The GBRL will apply this technique to several important domains of air quality and building science research, including human VOC emissions and interactions, indoor heterogeneous chemistry, and urban surface-atmosphere exchange processes. Check out the pictures from the install and training late last week:


November 8th, 2016

GBRL research is in the spotlight at GBRL Director Elliott Gall was interviewed for an article concerning ventilation rates, indoor air quality, and health. In the article, Dr. Gall discusses a recent publication that measured CO2 exposure in a cohort of subjects in Singapore, as well as work investigating the effectiveness of CO2 sorbents. A relevant excerpt about Dr. Gall's study of CO2 exposure from the article is below, and the full article can be found at Building Green (or click the photo below from the article)

Another study conducted in Singapore tracked CO2 exposure levels by attaching sensors to 16 individuals and observing exposure levels throughout a period of one week. Nearly all participants spent at least an hour of a typical day with CO2 elevated over 1,100 ppm. In this study, it turned out that a major determinant of more exposure was the mode of bedroom ventilation; people who used air conditioning units in their bedrooms instead of natural ventilation had many more instances of exposures to high CO2 levels and were also the only group that experienced CO2 levels over 2,500 ppm. For everyone in the study, the vast majority of significant exposure events—where CO2 levels fell between 1,000 ppm and 2,500 ppm for 2.5 hours or more—occurred in the home, whereas only 9% of those events occurred in an office.

“We have to understand the places where these exposure events occur,” Elliott Gall, Ph.D., lead author on the paper, told BuildingGreen. “Most studies are focusing on mimicking office environments, when what we found was that residences can be much worse.” While that was just one small study done in Singapore, other studies corroborate that offices tend to not have as much trouble with elevated CO2 levels (though problems are common in meeting or conference rooms with high occupancy levels); in a 2008 survey of 100 U.S. offices, only 5% of the measured peak indoor CO2 concentrations exceeded 1,000 ppm.

November 2, 2016

Dr. Gall was the most cited ResearchGate researcher in the MME department for the month of October! 

October 25th, 2016

GBRL researcher and Ph.D. Candidate Omed Abbass (in collaboration with David Sailor and Elliott Gall) received word that the article entitled "Effect of fiber material on ozone removal and carbonyl production from indoor carpets" was accepted to Atmospheric Environment. Congrats, Omed! This article looked at six types of carpets with varying pile type (the fibrous part that you step on) for uptake of ozone and, importantly, what byproducts result from that interaction with ozone. Carpets are an important indoor material due to their high coverage area in many indoor environrments; they also generally exhibit a fairly strong pathway for ozone removal and often form oxygenated VOCs which emit into the indoor environment as secondary emissions. 

Find more here:

October 20th, 2016

The Gall Research Group received word the paper entitled "Investigating CO2 removal by Ca- and Mg- based sorbents with application to indoor air treatment" was accepted to the journal Building and Environment this week. This paper looked at four sorbents and extensively characterized physico-chemical properties related to their capacity to remove indoor CO2, with particular focus on shelter in place facilities which are characterized by very small volume (5-10 cubic meters), high occupant density, (2-4 people in that small volume) and very low ventilation rates. These conditions are essentially worst case for exposrues to CO2 - modeling shows levels may quickly reach in excess of 10,000 ppm, where acute health effects may be of concern. The modeling suggests low cost sorbents may be effective in shelter in place conditions when indoor-outdoor air exchange may be limited due to adverse outdoor conditions (e.g., hazardous air quality due to chemical release). 

Access if free for the next 50 days here:

September 9th, 2016 

GBRL Director Elliott Gall and Ph.D. Candidate Omed Abbass presented an overview of GBRL capabilities at the 2016 Oregon BestFEST in downtown Portland. A great opportunity to see the work being done at other OregonBEST funded laboratories. The conference highlighted the activity of startups in the Northwest, with several compelling "pitches" given by startups in the building sciences arena, including a startup focused on 'energy efficiency as a service' and a startup looking to improve building automation in multifamily dwellings. Great stuff. 

September 2nd, 2016



GBRL Director Elliott Gall and GBRL Undergraduate Researcher Dreonna Johnson at the REU Symposium

GBRL Undergraduate Researcher Dreonna Johnson presented the findings of her summer research experience as part of the PSU Center for Climate and Aerosol Research NSF REU program. Her project was titled: Development of a low cost platform for personal, real-time monitoring of activity and exposures to multiple air pollutants. She made several excellent presentations at the symposium: a poster presentation and a 7-minute "flash" presentation highlighting the results of her study. Dreonna's work combined several off-the-shelf sensors that she assembled into a "personal monitoring kit" that enabled real-time monitoring of personal levels of CO2 (carbon dioxide), CO (carbon monoxide), TVOC (total volatile organic compounds), and PM (particle concentrations). In addition, she collected a unique dataset of quantitiative metrics of activity, including accelerometer data, GPS location, speed, and step count. Analysis continues on this dataset, but preliminary findings show correlations between CO2 and TVOC in certain indoor locations (but not all) as well as transient, elevated levels of pollutants during specific activities. For example, one subject involved in the study had personal TVOC levels elevated by ~3 orders of magnitude when blow drying her hair. 

Dreonna will return to UCLA to complete her undergraduate studies - best of luck! 


August 10th, 2016


Funding was granted by the National Science Foundation (NSF) in 2016 to investigate the effects of ecoroofs on indoor air quality. Research goals respond to two key questions: 1) How does the design of a building rooftop affect deposition, processing, and emissions of air pollutants? and 2) How might ecoroofs affect indoor air quality? This project will address these questions with a combination of techniques that integrate ecology, biology, and building science approaches. Specific investigations will include a broad field survey of 48 roof surfaces in Portland, OR, an intensive air quality monitoring study at a commercial facility with a dual ecoroof/white membrane roof, and bench-scale laboratory investigations. Field measurements and laboratory parameterizations will be used in statistical models and material balances to explain relationships between the urban environment, ecoroofs, and indoor air quality.