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The Weight of Numbers: Air Pollution and PM2.5

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Re: The Weight of Numbers: Air Pollution and PM2.5

#41

Post by gh02t »

bigmit37 wrote: post #28
gh02t wrote: post #3

I recently built a sensor for particulate matter (using the Plantower PMS7003, a laser-based sensor) and it's interesting to look at the effects of every day tasks. Cooking for instance causes a huge spike in PM1.0/2.5/10.0 levels, but so do more mundane tasks like vacuuming or spraying aerosols. I'd like to add a sensor for CO2, but it's a bit more complicated. A lot of the easy to use sensors marketed for the purpo…

Do you have any recommendations for sensors I can buy? I don’t know If I would be able to build one.

Not off the top of my head, but here's a tutorial on how to build one. The Plantower sensors are pretty easy to use.

https://learn.adafruit.com/pm25-air-quality-sensor/overview

Re: The Weight of Numbers: Air Pollution and PM2.5

#42

Post by staikken »

b_b wrote: post #23

I'd recommend anyone who would like to clean the air of the home to use products from SmartAir [1] which is as inexpensive as just a fan attached to a filter, both of which they sell (although you can just buy the filter by itself and attach it to a fan you already own). I visited their office in China and received a complementary filter, which when installed in my hotel room in Beijing, definitely cleared the air an…

I've worked for a company that measures PM2.5 in the past. Using a HEPA filter to remove PM2.5 seems unlikely to me. Perhaps there's something more going on here than I've picked up from a quick skim of the site (perhaps there's some sort of cyclonic separation happening) but I'm skeptical this is actually removing particulate at that scale.

Re: The Weight of Numbers: Air Pollution and PM2.5

#43

Post by SECProto »

graeme wrote: post #22
gascan wrote: post #9

Earlier quoted context omitted.

Cooking with gas or electricity? I've heard before that cooking with gas causes significantly more indoor air quality problems, but I'm curious what your observations are.

My electric stove shoots my AQI through the roof when frying. Made me consider alternate ways to cook. Though, would like to know if gas is worse, as one alternative I was considering was Donabe, which requires gas.

A fume hood that keeps splatters in and vents a lot would work. I think it's just unavoidable that frying vaporizes/aerosolizes particles, so your options are either vent the contaminated air, or don't fry.

Re: The Weight of Numbers: Air Pollution and PM2.5

#44

Post by coconut_crab »

I have always wondered what is the relationship between PM2.5 measurement and humidity/dew point. From what I have read all three types of PM2.5 sensors (beta ray, particle counting...) can't tell the difference between dust particles and water droplet. Googling around gives me a lot of conflicted answer[1][2][3].

If one looks at the air quality graph of my city[0], it can be seen that summer has much better AQI while winter/spring are worse. But I feel summer is much more dustier and spring is cleaner because the street is always wet from drizzle (dust is prevented from floating in the air). Maybe it has something to do with the lower dew point during winter/spring as my city has very high humidity, from 60% to 100% (right now it is 90%).

[0] http://hanoiair.de/en_US/

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555266/

[2] https://www.ncbi.nlm.nih.gov/pubmed/29063278

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072227/

Re: The Weight of Numbers: Air Pollution and PM2.5

#45

Post by sundvor »

sberder wrote: post #26
qiqing wrote: post #7

Earlier quoted context omitted.

Do you recommend the air purifier that you have? And would you mind sharing which one has a built-in sensor? I'd like to try measuring my laundry room.

Most purifiers on the market with built-in sensors are unreliable to measure. They usually go for cheap IR sensors without flow control. Your results will vary wildly depending on conditions (temperature and humidity affect measurements a lot). I personally like Xiaomi purifiers for their affordability and noise level. If you're concerned about measuring pm2.5 in your space, you should consider buying a good entry le…

We have a Coway AP-1008DH, and it's interesting to see how quickly it comes on when cooking. Probably cheap sensors, but it appears to be a good device overall.

I see that Air Visual ship to Australia; could this be a good way to assess the pollution levels at the school we're considering moving our son to (see my other response in this thread), or could there be cheaper options? Thanks!

Re: The Weight of Numbers: Air Pollution and PM2.5

#46

Post by ridgeguy »

gh02t wrote: post #3

I recently built a sensor for particulate matter (using the Plantower PMS7003, a laser-based sensor) and it's interesting to look at the effects of every day tasks. Cooking for instance causes a huge spike in PM1.0/2.5/10.0 levels, but so do more mundane tasks like vacuuming or spraying aerosols. I'd like to add a sensor for CO2, but it's a bit more complicated. A lot of the easy to use sensors marketed for the purpo…

> ...it's interesting to look at the effects of every day tasks.

I suspect pretty much every task elevates PM levels.

I made a somewhat surprising and definitely unwelcome discovery by turning off the lights in my bathroom, flushing, and shining a green laser pointer around (Rayleigh/Tyndall scattering, etc.). Followed up with the same test while scuffing my feet on carpet and doing a few other everyday activities.

It was interesting, so I'd recommend trying it at home, but not right before dinner. Or breakfast. Or ever, if you have an overly vivid imagination.

Re: The Weight of Numbers: Air Pollution and PM2.5

#47

Post by sberder »

sundvor wrote: post #32
clumsysmurf wrote: post #11

Its probably worse that it looks "Researchers from Queen Mary University of London have found that people exposed to air pollution levels well within UK guidelines have changes in the structure of the heart, similar to those seen in the early stages of heart failure." https://www.sciencedaily.com/releases/2018/08/180803103315.h...

That's interesting. We're looking at moving our son to a new school that's right at the corner of two major artery roads in Melbourne, with some 17 000 vehicles passing daily (just on one of them) according to VicRoads. The building doesn't appear to have a HVAC/filtration system. Playground is behind the building, but still has significant back traffic and is inside of 100-300 metres from the main roads. I'm saying…

You should be concerned as many research shows:

* leaving close to a busy road raises the risk of early dementia [1]

* higher risk of asthma

* cardiac arythmia

I could go longer but don't want to get too dark

For your situation, I think a laser egg from kaiterra is a good machine, you can bring it around and is reliable on the long run. They use a plantower sensor (mentioned in another comment) but have their own firmware on to interpret the readings. I know the founder of kaiterra personnaly so I might be biased but I'm not the only one in the industry recommending it for home use. The laser egg 2 is also measuring TVOC but is a bit more expensive, you might want to look into that. Overall a good and reliable machine for this price.

You would also like to consider PM10 in Australia, from memory, the dryness of the country and heavy farming in certain areas was producing a lot of bigger particles.

You can also track public data on sites like aqicn.org [2] or openAQ [3] (though the data looks sparse for Australia there).

[1] https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

[2] http://aqicn.org/map/#@g/-37.8328/144.8348/11z

[3] https://openaq.org/#/map?_k=ej77x9

Re: The Weight of Numbers: Air Pollution and PM2.5

#48

Post by sberder »

sundvor wrote: post #45
sberder wrote: post #26

Earlier quoted context omitted.

Most purifiers on the market with built-in sensors are unreliable to measure. They usually go for cheap IR sensors without flow control. Your results will vary wildly depending on conditions (temperature and humidity affect measurements a lot). I personally like Xiaomi purifiers for their affordability and noise level. If you're concerned about measuring pm2.5 in your space, you should consider buying a good entry le…

We have a Coway AP-1008DH, and it's interesting to see how quickly it comes on when cooking. Probably cheap sensors, but it appears to be a good device overall. I see that Air Visual ship to Australia; could this be a good way to assess the pollution levels at the school we're considering moving our son to (see my other response in this thread), or could there be cheaper options? Thanks!

We do work with a lot of schools here in SEA. not in Australia yet but AFAIK the market is probably not ready yet.

Re: The Weight of Numbers: Air Pollution and PM2.5

#49

Post by gh02t »

ridgeguy wrote: post #46
gh02t wrote: post #3

I recently built a sensor for particulate matter (using the Plantower PMS7003, a laser-based sensor) and it's interesting to look at the effects of every day tasks. Cooking for instance causes a huge spike in PM1.0/2.5/10.0 levels, but so do more mundane tasks like vacuuming or spraying aerosols. I'd like to add a sensor for CO2, but it's a bit more complicated. A lot of the easy to use sensors marketed for the purpo…

> ...it's interesting to look at the effects of every day tasks. I suspect pretty much every task elevates PM levels. I made a somewhat surprising and definitely unwelcome discovery by turning off the lights in my bathroom, flushing, and shining a green laser pointer around (Rayleigh/Tyndall scattering, etc.). Followed up with the same test while scuffing my feet on carpet and doing a few other everyday activities. I…

I dunno. I'm not really convinced that all particulates are automatically harmful at modest levels, at least not to a degree that is worth worrying about. The stuff that worries me are aerosolized modern pollutants- things like smog, glass dust from cutting fiberglass (particularly nasty stuff), and in the future potentially even new wonder materials like carbon nanotubes.

An air purifier with a HEPA filter and an ionizer will take care of the majority of visible airborne household dust, if it really bothers you.

Re: The Weight of Numbers: Air Pollution and PM2.5

#50

Post by sberder »

staikken wrote: post #42
b_b wrote: post #23

I'd recommend anyone who would like to clean the air of the home to use products from SmartAir [1] which is as inexpensive as just a fan attached to a filter, both of which they sell (although you can just buy the filter by itself and attach it to a fan you already own). I visited their office in China and received a complementary filter, which when installed in my hotel room in Beijing, definitely cleared the air an…

I've worked for a company that measures PM2.5 in the past. Using a HEPA filter to remove PM2.5 seems unlikely to me. Perhaps there's something more going on here than I've picked up from a quick skim of the site (perhaps there's some sort of cyclonic separation happening) but I'm skeptical this is actually removing particulate at that scale.

I'm not sure I get what you're saying here, HEPA is a standard that was developed for medical environments & clean rooms [1]. To qualify as HEPA, a filter should be able to remove 99.97% of particles 0.3µm and above so it is definitely impacting PM2.5 (particles 2.5µm and below).

See my other comment [2] for my opinion on smartair solutions.

[1] https://en.wikipedia.org/wiki/HEPA [2] https://news.ycombinator.com/item?id=17720802

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