Comments on new working paper ‘Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program’

Economists Meredith Fowlie and Catherine Wolfram at the University of California, Berkeley and Michael Greenstone at the Energy Policy Institute at the University of Chicago (EPIC) have published a new working paper on the economics of residential energy efficiency retrofits, in which they present some discouraging results:

I first read the short research summary from EPIC, “Costs of Residential Energy Efficiency Investments are Twice their Benefits: Implications for Policy,” and found some surprising conclusions that led me to dig deeper into the actual working paper, “Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program.”

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Literature round-up: June 2015

It’s been forever since I’ve done one of these literature round-up posts, but you could say that about a lot of post types on here….

Regardless, here are a few recently published papers that I find really interesting:

  • Ji and Zhao, 2015, PLoS ONE, Estimating Mortality Derived from Indoor Exposure to Particles of Outdoor Origin – this is a really important effort to combine outdoor air pollution data (PM2.5 and PM10) with a mechanistic understanding of how outdoor particles infiltrate into indoor environments (where we spend most of our time) and estimate the impact of indoor exposure to particles of outdoor origin on mortality. Basically: in the US, Europe, and China, our indoor exposures to outdoor PM account for about 80 or 90% of the mortality associated with outdoor PM. This is something I’ve been thinking about and saying for several years now, so I love to see the work that Bin Zhao and his group are doing at Tsinghua University!
  • Bouslimani et al, PNAS, Molecular cartography of the human skin surface in 3D – This one is intense — basically, our bodies are literally covered with both chemicals and microbes, but the chemical makeup of skin surfaces aren’t well understood in total. This paper swabbed the hell out of some peoples’ skin and performed mass spectrometry (for the chemicals) and 16S rRNA sequencing (for the microbes) and made a 3D map of the data. They ended up with some wild human chemical/microbial plots like this:


  • Langevin et al, Building and Environment, Simulating the human-building interaction: Development and validation of an agent-based model of office occupant behaviors – This is very cool work that develops and validates an agent-based model of occupant behavior using data from a long-term field study in an office. Basically the ‘agents’ in the model can reasonably accurately mimic the real life occupants and make decisions about whether or not to turn on a fan, heater, or open a window based on their current thermal comfort levels and sensations. This is really important work to see published.
  • Jiao et al, ES&T, Field Assessment of the Village Green Project: An Autonomous Community Air Quality Monitoring System – cheap air quality sensors, low cost air quality monitors, or whatever you want to call them are HUGE right now. It really seems like people want to know what they’re breathing and want to be able to understand it accurately and inexpensively. It’s a sort of holy grail for any field. This paper reports a field assessment of a solar-powered air monitoring park bench that could measure ozone, PM2.5, and meteorological parameters and stream the data to the public. They were able to collect a bunch of data in Durham, NC, and had relatively decent correlations with nearby federal equivalent method (FEM) monitors (in English: regulatory monitors). Very cool.

20 papers every BERG student should read

My colleague Michael Waring, who directs the Indoor Environment Research Group at Drexel University, recently shared a thought with me. He was thinking about compiling a list of about 20 papers that every graduate student in his group should read and be very familiar with. It’s a great idea, so here I am doing the same.

Below is a list of 20 papers I think every Built Environment Research Group student (BERGer) should read. Narrowing to only 20 papers is tough. In fact, this may forever be considered a rough draft of a list, and it will most certainly change or expand over time. But I have chosen these articles to span a wide range of topics related to energy and air quality in the built environment, including the physics or chemistry of indoor air pollutants, human exposure to indoor pollutants and health effects, and energy efficiency in buildings. There may be other even better articles on each topic, but these were chosen for their combination of impact on research and thought in their areas of inquiry, the usefulness of their methods, their clarity in presentation, and for the references included within them as well as their links to other papers that have referenced them upon publication.

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Air quality monitoring on Metra trains in Chicago, IL


We recently partnered with investigative reporter, Dave Savini, from CBS 2 Chicago to make air quality measurements in and around Metra trains and train stations in downtown Chicago. The Chicago Tribune had previously reported high concentrations of soot (black carbon particles) onboard trains over 3 years ago, which were thought to be caused by re-entrainment of diesel engine exhaust. We know that diesel exhaust emits a number of pollutants that are problematic for respiratory and cardiovascular health, including ultrafine particlesblack carbon particles, metals, and VOCs and SVOCs. This report prompted Metra to take action, primarily by installing particle filters on the cabin ventilation systems (MERV 13 instead of MERV 8) and by installing (or planning to install) devices that shut-off the diesel engines as they enter stations. The filters were shown in 2011 to measurably reduce black carbon particle concentrations in the rail cars, which was good to see. I’ve also found links to documents showing that Metra was upgrading ventilation systems to include vent hoods on intakes and exhausts, manual closing of outdoor air dampers, and exhaust deflectors on the locomotives themselves. I’m not sure of the status of these repairs or the extent to which MERV 13 filters have been installed across the fleet.

UPDATE: Watch a video of the CBS 2 story

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EPA Integrated Science Assessment for Particulate Matter

In case you aren’t familiar with this report, I’m simply linking to the 2009 EPA Integrated Science Assessment for Particulate Matter (direct pdf download) here because I find it to be an extremely exhaustive look at the nature of airborne particulate matter, aerosol science, sample collection methods, geographic differences across the U.S., inhalation and respiratory deposition, and acute and chronic health effects. I’ve taught from it directly and I’ve used it to inform research and my own opinions on PM exposures. It weights in at a whopping 2,228 pages! Here are a few screenshots of what I find to be some of the most helpful parts: