honk · HackerTrans

You may know this already, but both Olin Foundations are good examples, actually. I believe the John M. Olin foundation dissolution plans were specifically in response to the Ford foundation's drift. The F. W. Olin foundation (John's Father) coincidentally dissolved in the same year, but that was due to largely accomplishing their original goal of endowing engineering buildings at colleges, and pivoting to founding a new engineering college entirely.

honk

2 jaar geledendiscuss

This reference instrument variability is especially true of the BAM, which due to its measurement technology has a high "noise floor" at low concentrations, while remaining a fairly good measurement at high concentrations. I believe two identical BAMs next to each other can easily have more than 25% disagreement at the lower end of the concentration range.

The T640 also recently had its approved calibration algorithm(s) updated, to a new set which often reads about 7% lower. What does that mean for T640 reference data collected in the past? I don't know, and AFAIK neither does the EPA really.

All that to say that reference instruments are still instruments with limitations, even if from a regulatory perspective we treat them as "truth".

honk

3 jaar geledendiscuss

It's a little messy, and it's not clearly disambiguated what concept the artist is referring to. I agree "Hydrocarbon emissions" could reasonably mean what you get when you burn hydrocarbons, but that definition can also include literal "Hydrocarbon emissions": uncombusted or partially combusted hydrocarbon fuel being emitted out of the exhaust after ignition due to non-ideal combustion. Like you mention, this is alongside CO, as well as elemental black carbon and other trace combustion products like NOx etc...

You're right that there isn't orders of magnitude more CO2 from a two stroke, but there are orders magnitude more CO, as well as these literal "emitted hydrocarbons", which I think it what the direct claim the art intends to illustrate with either dinfinition. But the fact we're having this conversation is evidence the claim at the very least isn't clear.

honk

3 jaar geledendiscuss

That's a fair point, although I'm not sure I'd personally categorize it as "actively deceptive", I agree it could be a lot clearer about "Emissions", and empirically you're clearly right that is has some folks confused. To be charitable, like all science communication it's trying to simplify a very nuanced topic and probably could be improved. I do think the illustration of how leafblowers pollute at ~300x the rate a car does is largely true, and the GHG/environmental impact is a lot messier than just primary CO2 emissions.

(Disclaimer: I've never met or interacted with Nicole, but I know people that have, so I'm likely biased to assume good intent.)

honk

3 jaar geledendiscuss

I link some sources in a separate comment up-thread, but the short answer is two stroke engines run orders of magnitude "dirtier" than a four stroke in a car, primarily due to incomplete combustion of fuel. (Some of this is fundamental to the physics of their operation, and some of this is they aren't subject to the same strict automotive emissions standards, so less engineering goes into reducing their emissions)

Intuitively, this is why you can sometimes taste a lawnmower running the next block over in the air, but the same isn't true for a modern car idling, even if they were consuming fuel at the same rate.

honk

3 jaar geledendiscuss

First off, kudos for putting in the effort to critically think through the implications of stats you see!

Actually, the counterintuitive truth is that two-stroke engines produce ~300-500x more PM/hydrocarbon emissions from the same amount of fuel use than a four-stroke engine, due to the fundamental nature of incomplete combustion and the oil-fuel mixture used in two stroke engines, and the efficacy of emissions controls on modern cars vs common leaf blowers. Your calculations are correct, it's just this difference is so big it seems crazy when you first learn about it. (Which is what Nicole's art is trying to communicate!) This is cited in the NYT article from the tweet you link: https://www.edmunds.com/about/press/leaf-blowers-emissions-d... , although for a more scientific source you can see https://publications.jrc.ec.europa.eu/repository/bitstream/J... .

While technically, carbureted two-stroke engines can sometimes produce less NOx than four-stroke fuel-injected counterparts for equivalent fuel use, incomplete combustion means leaf-blowers and the like have a massively outsized impact on air quality, especially for the operator. The good news is that electric systems are now cheap and lightweight enough for most applications, which is fantastic.

honk

3 jaar geledendiscuss

Thanks for the interest! We have transparent pricing here: https://quant-aq.com/pricing

Short answer, $1500 + $300 annually (includes cellular, realtime data calibration in our cloud, and full API access).

Relevant to the topic above, we are building for a slightly different market than AirGradient, and want to make sure we're an appropriate solution for potential customers -- you might genuinely be better served by a different product! As such, we're currently not optimized for low touch single sales to individuals, but it's something we'd like to improve in the future.

If you do contact sales, and we end up being a good fit for what you're looking for, we'd love to help!

honk

3 jaar geledendiscuss

Relevant disclaimer: I work for QuantAQ, another distributed Air Quality Monitoring company, my opinions are my own.

With proper calibration, the PMS5003 sensor AirGradient uses is a real and fairly good measurement of PM1 (<1 micron), which is often fairly correlated with (and makes up much of) PM2.5. However, the sensor cannot really see particles larger than 1 micron, which sometimes matters for PM2.5 (when the PM1:PM2.5 ratio changes, like wildfires), and very much matters for PM10. That's why QuantAQ uses a PMS5003 combined with a different sensing technology (an optical particle counter) to actually measure PM2.5 and PM10, not just extrapolate from a PM1 measurement.

We have a blog post here explaining more: https://blog.quant-aq.com/can-your-plantower-pms5003-based-a...

I love the work that AirGradient is doing making AQ sensing technology open and accessible, especially to hardware hackers. The BOM cost of the OPC sensor we use alongside the PMS5003 is more than the cost of the entire AirGradient kit, so it is valuable to have options in the market depending on application.

honk

3 jaar geledendiscuss

QuantAQ | Full-stack Software Engineer | Somerville, MA; San Francisco, CA; Remote (US) | Full-Time | https://quant-aq.com

At QuantAQ, we build air quality sensors and software to help customers measure, understand and act upon the air around them. In other words, digital twins for air quality. We're a very small team that is growing, profitable, and doing genuinely fun and impactful cleantech work.

We are looking to hire a software engineer to help us build out our cloud platform for air quality sensor networks: you'll have to be comfortable full stack, and hopefully you're a better front-end engineer than any of us are. Our web stack is mainly Python (flask), Postgres and Docker, with more buzzwords in the job ad.

To apply: https://jobs.ashbyhq.com/quant-aq/72bb5a30-e771-4a1d-9162-a1...

(Like Hardware? We're also hiring a generalist IoT engineer: https://jobs.ashbyhq.com/quant-aq/9fda1389-730d-4e5d-943c-ac... )

honk

3 jaar geledendiscuss

QuantAQ | Full-stack Software Engineer | Boston, San Francisco, Remote (US) | Full-Time | https://quant-aq.com

At QuantAQ, we build air quality sensors and software to help customers measure, understand and act upon the air around them. In other words, digital twins for air quality. We're a very small team that is growing, profitable, and doing genuinely fun and impactful cleantech work.

We are looking to hire a software engineer to help us build out our cloud platform for air quality sensor networks: you'll have to be comfortable full stack, and hopefully you're a better front-end engineer than any of us are. Our web stack is mainly Python (flask), Postgres and Docker, with more buzzwords in the job ad.

To apply: https://jobs.ashbyhq.com/quant-aq/72bb5a30-e771-4a1d-9162-a1...

( We're also hiring a director of Sales: https://jobs.ashbyhq.com/quant-aq/d7168eba-fb32-40ac-ad68-ff... )

honk

8 jaar geledendiscuss

I believe edraferi is just asking why you chose to use a 1-indexing system vs a 0-indexing system. https://en.m.wikipedia.org/wiki/Zero-based_numbering

Interesting note: Dewey Decimals are zero indexing. And of course, "000" is for computer science.

honk

8 jaar geledendiscuss

I've been fortunate enough to take a class with Sanjoy (The author) covering this book. It was an incredible experience, and he's one of the best mentors I've ever met.

One of the things I found most interesting from the class that you couldn't get from the book was a particular method of assessment. He would pose a question, and allow you to give a weighted answer across a few options, to better understand your uncertainty. It was a very useful pedagogical technique, and allowed me to quantify my understanding in a very tangible way.

I highly recommend the whole book, but especially the first section, on breaking things down.

honk

8 jaar geledendiscuss

To further the aside, there are many Olin buildings on college campuses, all due to Franklin W. Olin (the founder of the Olin corporation). There is also now an entirely standalone Olin College, which is the biggest shared name with this project in my opinion.

honk

8 jaar geledendiscuss

Congrats on the launch! You guys seem like a very different take on "computational biology". As a heads up, it looks like the twitter link on your site just redirects to the contact form.

Good luck!

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