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-peas- t1_jcgv5ro wrote

Reply to comment by Tactically_Fat in Open-source tool from MIT’s Senseable City Lab lets people check air quality, cheaply. by chrisdh79

I made & coded my own array of various sensors and have a blower/laser pm2.5 sensor, and I care not about its scientific accuracy, but I care about its ability to be able to tell me when air quality on my deck gets worse. It does that immediately with an LED that shines into my window with various colors depending on EPA air quality math. It could be huge percentages off scientifically accurate, but its going to tell me that the air quality got much worse. Its pm2.5 numbers are close to other stations around me regardless, but it definitely isn't a scientific instrument.

I'm not sure if most people buying these things care about its scientific accuracy, mainly just if things are getting worse outside.

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CARLEtheCamry t1_jchpkey wrote

I live less than 20 miles downwind from East Palestine. In the immediate aftermath local subs were full of panic posts about "omg death cloud, look at PurpleAir!".

Turns out it just got cold, and people burned wood. Happens frequently with the Cracker Plant as well, people try to correlate PurpleAir with it, it's always wood burners.

You're using the sensors right. It should be more of general guidance, leave the actual testing to scientists. Like, I wouldn't walk into a hazmat scene with my air purifier if it's sensor was green.

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Tactically_Fat t1_jcgvy1s wrote

> scientific accuracy

But that's, like, the only real way to know for sure. Otherwise - it's either speculation or generalization?

Accuracy, repeatability, and defensibility.

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what595654 t1_jcgzrjl wrote

Did you not read what he said? You are just looking at whether it goes up or down. Being perfectly accurate is not necessary.

Its like if you had a weight scale. If it told you, tomorrow that you gained 15.3 lbs, and you repeated... and it said 13.9 lbs... 17.6 lbs, so on. It doesnt matter the exactness. The point is, your weight went up a lot in one day. That is good enough to make decisions on. Not for scientific studies.

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