Peter DeCarlo, PhD – Drexel University – What can Kathmandu teach us about HomeChem? – Governed by the chemistry around us

Air Date: 10-19-2018|Episode 521

Dr. Peter DeCarlo is an Associate Professor with appointment in the Department of Civil, Architectural, and Environmental Engineering, and the Department of Chemistry at Drexel University.  He is also an affiliate of the Urban Health Collaborative in the School of Public Health at Drexel University and an adjunct member of the Center for Excellence in Environmental Toxicology (CEET) at the University of Pennsylvania.

Full Description:

Dr. Peter DeCarlo is an Associate Professor with appointment in the Department of Civil, Architectural, and Environmental Engineering, and the Department of Chemistry at Drexel University.  He is also an affiliate of the Urban Health Collaborative in the School of Public Health at Drexel University and an adjunct member of the Center for Excellence in Environmental Toxicology (CEET) at the University of Pennsylvania.  Dr. DeCarlo has a Ph.D. in Atmospheric Science from the University of Colorado, and a BS in Biochemistry from the University of Notre Dame. He uses state-of-the-art instrumentation to measure the chemical composition of particulates and gases in indoors, outdoors, and in the laboratory to better understand the intersection between air quality, health, and climate impacts of human emissions.  He has made air quality and climate related measurements from planes, trucks, and stationary sites all over the world to better understand direct emissions, sources, and subsequent chemical reactions of pollutants in the atmosphere.

More recently Dr. DeCarlo has begun measuring the relationship between outdoor and indoor air pollutants, to understand transport of outdoor pollutants to the indoor environment, and to identify indoor specific sources such as residual tobacco smoke, and direct human emissions. He also is interested in the intersection of science and policy and was an AAAS Science Policy Fellow at the US EPA working on issues related to clean cookstoves in the developing world and public sharing of environmental data prior to starting his faculty position at Drexel.  Funding for his research comes from the National Science Foundation, Sloan Foundation, Electric Power Research Institute, Camille and Henry Dreyfus Foundation, and the Department of Transportation. Dr. DeCarlo has co-authored over 80 peer reviewed publication and has been identified as a highly cited researcher by Clarivate Analytics (2014, 2015, 2016, and 2017).

Z-Man’s Blog:

“All we do is governed by the chemistry around!”
Dr. Peter DeCarlo is an Associate Professor at Drexel University. He uses state-of-the -art instrumentation to measure chemical composition of particles and gases indoors, outdoors, and in the laboratory to better understand then intersection between air quality, health, and climate impacts of human emissions.
He started at Drexel as an Environmental Engineer with expertise and experience in Outdoor Air where he teamed up with Mike Waring whose expertise and experienced was in Indoor Air.
Nuggets mined from today’s episode:
Uses the terms aerosol and particle interchangeably.
The aerosol mass spectrometer developed and widely used for the study of outdoor air is his workhorse instrument for studying indoor air. He started using it to study indoor air when he started at Drexel as a collaboration with Dr. Michael Waring. The instrument is valued at ~$500K. Learning outdoor air and indoor air are different as subtle differences exist. 4 different month long measurements of indoor and outdoor air have been taken.
Wrote a paper on why the Field-Deployable High Resolution Time-of-Flight Mass Spectrometer is so useful for studying indoor air. Weighing 500 pounds the device has wheels, is portable, plugs into a standard electrical outlet and is an improvement over the Quadruple Mass Spectrometer and can measure nanograms per M³. He has used the device in Antarctica and found it the cleanest place he has ever measured.
US Embassies are interested in air quality for the staff and families who work there, which took him to Nepal. The air in Nepal has more particulate matter in winter than in summer. Attributes this to seasonal dryness where there is more burning of solid fuels and indoor cook stoves. Air is cleaner during the monsoon season. Students used air filtration devices in their sleeping rooms to help protect them from the indoor penetration of outdoor air. His experience is that the air in Nepal was never as clean as the air in the US.
The study of outdoor air was prompted by concern over potential health issues. We spend 90% of our time indoors where occupants are exposed to outdoor pollutants that end up indoors.
Knowledge and experience with aerosols outdoors helps him understand indoor air. His research was a wakeup call.
Presented at Indoor Air 2018- “Human Impact to Indoor Air Quality”. Discussed the Human Occupant Contribution to Secondary Aerosol Mass of secondary aerosol mass. Direct emissions are primary for example: visible black smoke emitted by a diesel bus. Secondary emissions are gases that react to form lower vapor pressure products that go to particles and increase total aerosol mass.
Humans are an indoor sources of CO² and when we see an increase in CO2 there is a decrease in O³.
Human skin oil reacts with O³ forming chemicals which add particles and increase indoor aerosol mass.
The human impact of cooking and cleaning are the big indoor sources. For indoor spaces without strong sources, like a classroom at Drexel, sampling shows that 10% of particle mass during high occupancy was from people and 90% of particle mass originated outdoors.
Particle Matter Size and Composition Change in Response to Transport from the Outdoor to Indoor Environment. Contributory factors include: temperature gradient change, HVAC systems. Going from hot to cold encourages change from volatile/gas phase to particle phase, the opposite occurs during winter. Ammonium nitrate found indoors is from the combination of “cows and cars”. 90% evaporates indoor due to heat. The test area at Drexel is mechanically ventilated building pulling from the outside and filtering. Some pollutants are captured by the building envelope. The HOMEChem research building doesn’t pull air from the outside was higher than the Drexel building. At the University of Texas 2/3s of the outdoor aerosol came indoors as measured by nonvolatile sulfate. The size of particles being studied is <1 micron.
HOMEChem brings people together to measure everything we can think of. Peter was invited to participate in HOMEChem by Delphine Farmer and Marina Vance. Both Peter and Delphine started their careers as outdoor researchers. In the outdoor world all roads lead to Boulder. Total sticker cost of instruments used during HOMEChem were valued at roughly $4.5 million.
Factors Affecting Indoor Ammonia Concentrations (by Laura Ampollini). Cavity Ringdown Spectroscopy used to measure ammonia indoors. Compared to what was found outdoors ammonia levels 1-2 ppb, significant baseline ammonia levels of 30-40 ppb were found indoors. Ammonia is a sticky substance. Temperature increases ammonia concentrations. Feedlots contribute to ammonia levels outdoors. Ammonia (chemically a base) combines with acid gases and goes into particle phase forming ammonium sulfate and ammonium nitrate. Gas phase ammonia can remove other species from surfaces such as Environmental Tobacco Smoke. Mopping with bleach + indoor ammonia is being studied. Highest ammonia levels of 1 ppm occurred indoors when ammonia was used for cleaning.
Turkey, Toast and Particles: chemical characterization of PM1 emissions during cooking events (Erin Katz). Cooking is one of the largest sources of particles indoors. Studied the chemical composition of the particles. Interesting off-gassing occurs when using the oven. Oil is the main chemical signature. Oil phases include volatile and condensing. During study a propane stove was used, exhaust vents weren’t operating. NOx (oxides of nitrogen) and ultrafine particles measured.
Seasonal variation in the composition of outdoor to indoor transported submicron aerosols. (Avery, A.M., M.S. Waring and DeCarlo, P.F.). Summertime in Philly is different than winter. More photochemical reactions and more plant-life emissions occur in summer. Found more ammonium sulfate and ammonium nitrate emissions occur in winter 50% than in summer 25%. Attributed to differences in HVAC systems, air conditioning which creates wet surfaces that absorb water soluble gases. Sulfate is a tracer. Similar penetration during seasons. Different sources indoors. Less human related concentration during summer. Residual tobacco smoke found in a nonsmoking building.
3rd hand smoke exposure is an active area of research. 3rd hand smoke indoors is attributed to skin and clothing adsorption. Off-gassing combine with particles and become an inhalation exposure. Mouse model studies being used. Findings include respiratory problems and lower growth rates. Similar health impacts as 2nd hand smoke. Opines that evidence of occupant smoking should be added to Home Inspector’s checklists.
Did an experiment in which cigarette smoke was captured in a glass container. After the container was cleaned with soap and water and retested; it was found that smoke residue remained. Acid was needed to remove all traces of the smoke residue.
Particulates originate outdoors, people and human activities add complication.
No two indoor environments are the same.
Geographical affects indoor aerosols.
Outdoor research remains well funded, more funding is needed for indoor research. Sloan Foundation has pushed research forward. The National Science Foundation has funded some research, not at the Sloan level. Hopes for a kickstart of more funding.
We are building a foundation of fundamentals upon which more will be learned.
With only 5-7 years indoor research experience he’s new to field and finds it amazing and scary (when he thinks about risks to his kids).
If cigarette smoke is bad, fire related smoke and residues must be bad too.
Looking at effects of vaping indoors.
Plastic emissions in vehicles are accelerated by heat.
O³ and hydroxols react in gas phase and won’t be of help on particulate residues.
Sugar soap…. Its name arises from the fact that, when in dry powder form, it resembles table sugar. The solution is alkaline and its uses include cleaning paintwork in preparation for repainting.
Z-man signing off
Trivia Question:
What is timekeeping in Nepal based upon?
Trivia Answer:
The time in Nepal is based upon Mt. Everest.
Answered by:
Thomas Wesley Barnes lll
Greenville, SC