Science and Technology links (August 17th 2019)

  1. Google may soon release an augmented-reality version of Google Maps for mobile phones. I have always found it difficult to identify the streets I see in an unfamiliar setting, and it looks like Google may be solving this very problem. I am looking forward to seeing how well it works in practice.
  2. The delivery company UPS has been using self-driving trucks for some time. However the trucks are still manned by a driver and an engineer.
  3. Researchers have rejuvenated the brain cells of old rats. There is a press release.
  4. Blood pressure is an important health marker and it would be important to monitor it more broadly. There are cheap devices to measure blood pressure automatically, but they typically require that you put a strap around your arm. Researchers have shown that we can measure blood pressure using the camera of a smartphone. It remains to verify that it can work outside of the lab, in the real world.
  5. Are electric cars good for the environment? According to Holland et al., they are worse than gasoline cars on average, even though they may be preferable where you live:

    Ignoring local pollution leads to an overestimate of the benefits of electric vehicles and an underestimate of the geographic heterogeneity. Accounting for both global and local pollution, we find electric vehicles generate negative environmental benefits of 0.73 cents per mile on average relative to comparable gasoline vehicles. (…) On average, electric vehicles driven in metropolitan areas generate benefits of about $0.01 per mile while those driven outside metropolitan areas generate benefits of −1.7 cents per mile.

Daniel Lemire, "Science and Technology links (August 17th 2019)," in Daniel Lemire's blog, August 17, 2019.

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Daniel Lemire

A computer science professor at the University of Quebec (TELUQ).

5 thoughts on “Science and Technology links (August 17th 2019)”

  1. The paper by Holland on electric cars is interesting. It reaches the conclusion is does by assuming that the majority of the damage done by electric cars is not caused by greenhouse gas emissions, but by CO2, SO2, NOx, PM2.5, and VOCs. See Table 5 in the paper, where electric vehicles cause 1.7 cents/mile of non-GHG damage but only .8 cents/mile of GHG damage; compared to gasoline vehicles at only .5 cents/mile of non-GHG and 1.2 cents/mile of GHG.

    That is, they accept that gasoline powered vehicles have much higher CO2 emissions, but conclude that the other forms of pollution associated with electricity generation dominates the negative effects of electric vehicles. Personally I think this is quite probably true, but it’s also probably very contentious.

    They appear to do a sensitivity analysis for their cost assumptions in Table 7, but I’m not they really cover the range of CO2 costs that some people would argue for. Specifically, they use $30-$50 of cost per ton of CO2 (ie, the US government estimate +/- ~25%), while others argue that the actual cost is much higher, at several hundreds of dollars per ton:

  2. The Holland paper is that is based on the electricity grid in the years 2010-2012, so almost 10 year old data. I wonder why, maybe to make electric cars look bad? Since then, many coal plants are retired (specially the smaller ones that emit a lot of SO2, NOx and PM2.5). According to EIA “Changes in coal sector led to less SO2 and NOx emissions from electric power industry”, SO2 generation in 2016 is only a third of what it was in 2010, and for NOx almost half. Specially the very dirty coal power plants have retired.

    Then, you also should consider the forecast. Electricity production will become cleaner in the next years. If you can afford buying a new car, possibly you can also afford installing solar panels.

    See also Wikipedia “Environmental aspects of the electric car” and “Cleaner Cars from Cradle to Grave” (even though, that one is old as well).

  3. A recent episode of Skeptoid talked about electric cars, and explained that most reports claiming that electric cars pollute more, come from think tanks sponsored by industry, producing papers that are not published in legitimate science news. This paper also doesn’t seem to be published in one of those. A quick search shows it is found on several sites that claim to “promote the dissemination of ecological research to the public”, which sounds like beautifying spin doctoring.

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