
Realtime California Air Quality - gdi2290
https://www.purpleair.com/map?opt=1/i/mAQI/a10/cC4#7.22/37.494/-120.928
======
ilyagr
I've found [http://www.airnow.gov](http://www.airnow.gov) very helpful and
faster to load than the Purple Air map. They also have a simple but efficient
app.

Airnow's map is slow to load, but shows smoke, air monitors (including the
Purple Air ones^[footnote]), and fires all at once:
[https://fire.airnow.gov/?lat=37.40&lng=-122.077&zoom=10#](https://fire.airnow.gov/?lat=37.40&lng=-122.077&zoom=10#)

A less detailed, fast, static map for the SF Bay Area is available at
[http://www.baaqmd.gov](http://www.baaqmd.gov).

Last, but not least, there is a forecast of surface-level smoke available at
[https://hwp-viz.gsd.esrl.noaa.gov/smoke/](https://hwp-
viz.gsd.esrl.noaa.gov/smoke/). I found it from
[https://twitter.com/NWSBayArea](https://twitter.com/NWSBayArea), which is a
good source of news for the Bay Area.

[footnote]: To make the numbers match, I had to set PurpleAir to show One-Hour
Averages with the LRAPA scoring. See
[https://imgur.com/a/d6yFtow](https://imgur.com/a/d6yFtow).

~~~
krat0sprakhar
Didn't know about airnow.gov - thanks!

I'm surprised though why the data is so different between airnow and
purpleair. On AirNow, SF currently shows unhealthy air (150~) whereas
purpleair shows 88 (moderate). Which one of these is more reliable and real-
time?

~~~
karlding
Someone posted a Medium article [0] on the /r/bayarea subreddit where they did
some digging into this. Apparently the sensors used by Purple Air rely on a
constant that represents the average density of the particles it detects.
Because wood smoke particles are less dense than typical PM 2.5 particles, the
resulting AQI values are too high.

The Lane Regional Air Protection Agency has developed a conversion formula
that is built into Purple Air (if you apply the LRAPA conversion factor in the
UI), so you can have a better comparison.

[0] [https://medium.com/@16fcali/understanding-purpleair-vs-
airno...](https://medium.com/@16fcali/understanding-purpleair-vs-airnow-gov-
measurements-of-wood-smoke-pollution-562923a55226)

~~~
aaroninsf
^^^ this

That article is well worth a read. I now am using PA in this mode.

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modeless
I like PurpleAir's air quality map but felt it was a bit too slow to check
frequently. So I used their API to make the fastest air quality site around:
[https://aqi.today](https://aqi.today)

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khuey
For those who don't live here, a series of dry thunderstorms last weekend
sparked a number of wildfires that have combined to burn more than 1500 square
miles (more than 4000 square kilometers) in less than a week.

~~~
RobLach
Unfortunately the same conditions are reappearing which will negatively
compound the situation:

[https://www.chicoer.com/2020/08/23/national-weather-
service-...](https://www.chicoer.com/2020/08/23/national-weather-service-
upgrades-fire-weather-watch-to-red-flag-warning-in-parts-of-northern-
california/)

~~~
coronadisaster
at least, those 1500 square miles can't burn again... maybe CA need to do
controlled burns like FL does (if they don't already do it). IE: Burn dry
brush in the forests.

~~~
kec
I believe California does, but the scale of the problem is completely
different compared to a sate like Florida. California has 2.5x as much land as
Florida and a significantly higher percentage of the total land is wilderness
or otherwise undeveloped.

~~~
shaftway
Not just wilderness or undeveloped, but highly inaccessible to firefighting
crews. The Bay Area has peaks over 4000 feet with lots of fairly sheer areas.
Often firefighters have to be dropped in by helicopter.

Florida is mostly low rolling hills with the highest point in the state being
~350 feet above sea level. If Florida has a fire in an inaccessible area, it's
usually inaccessible due to water, so more of a help to firefighters than a
hindrance.

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supernova87a
Maybe someone can share/explain --

Purple Air _sells_ you a sensor that you can install, and then takes the data,
displays it on their website for lots of people to view, and then presumably
makes money off the data you send them? Why should you have to pay for the
sensor then?

~~~
IvyMike
Here's a NYT article on the origins of Purple Air.

[https://www.nytimes.com/2018/11/30/style/air-quality-
polluti...](https://www.nytimes.com/2018/11/30/style/air-quality-pollution-
monitors.html)

I have a Purple Air sensor; I view the money I spent on it as helping to
sponsor a "citizen science" project. Could the nature of the project change in
the future, to where I feel like I was taken advantage of? Sure, I guess. But
I'm ok taking that risk.

~~~
supernova87a
I see. Ok, well at least it's not some tech app service trying to charge on
the front end and make money off the back too.

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gdi2290
also see how bad the fires are from Santa Cruz
[https://twitter.com/robwormald/status/1296709260429029378](https://twitter.com/robwormald/status/1296709260429029378)

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ahaucnx
We are a new startup (currently doing Startup School) to provide air quality
monitoring solutions especially for schools.

From the beginning it was important for us to give back to the community so we
setup AirGradient for Education providing free tutorials and advise.

We just published our open source and open hardware air quality sensor
measuring PM2.5, CO2, Temperature and Humdity. So you can build your own
sensor with a small display to measure the air quality in and around your
home. We call it the AirGradient DIY sensor.

Build instructions, Code and Hardware files can be found on our project page:
[https://www.airgradient.com/diy/](https://www.airgradient.com/diy/)

It would be great to hear feedback from you!

PS: We are also looking for schools that are interested in improving air
quality to learn more about their needs and possible solutions. Please PM me
for more information.

------
Zhenya
Submitted a quick instruction on how to make an air purifier.

Link:
[https://news.ycombinator.com/item?id=24251509](https://news.ycombinator.com/item?id=24251509)

Copy/pasta to help folks:

Note: this is not my idea, but I have used it for 2 Cal fire seasons
successfully.

1) Acquire a box fan

2) Acquire a large "FPR 10" rated filter from home depot

3) Duct tape filter to the out flow side of the box fan. Make sure the arrows
on the filter point in the correct airflow direction.

This works dramatically well for very little dollars and can help save your
lungs if air purifiers are not available or expensive.

~~~
ilyagr
How loud is it?

~~~
Zhenya
Not loud at all. Just a background hum. However, I'm sure it's a function of
the box fan motor. I have a cheap one and it's perfectly fine to sleep in the
same room.

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Fauntleroy
It's useful to see the pollution numbers on the sensors, but it's also just as
interesting to see which sensors have been destroyed and for how long. You can
track the fire just by seeing when sensors go offline, if you know where to
look.

~~~
anamexis
Not necessarily destroyed, but at least without power.

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oski
Make sure to use the “LRAPA” conversion on purpleair.com

[https://twitter.com/rengiec/status/1296486310123905024?s=20](https://twitter.com/rengiec/status/1296486310123905024?s=20)

------
dang
See also: a thread from 2018:
[https://news.ycombinator.com/item?id=18714777](https://news.ycombinator.com/item?id=18714777)

------
Animats
Site down:

    
    
        Over Quota
        This application is temporarily over its serving quota.
        Please try again later.

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ericand
What's with indoor sensors being default on? Is there some value to then that
I don't understand?

~~~
stbtrax
This is very frustrating. Agreed, they should turn them off by default.

~~~
mjrpes
I sent their team an email two years ago with exactly that feedback, and their
response was:

"Thank you for the feedback. We are working on an update that will 'save' your
preferred map view when logged in on the PurpleAir website. However, it is not
published yet."

See my post above how I am able to bookmark the site after I choose the
settings I want and it remember these choices when I visit again.

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tempsy
this year is like a sad joke. if covid didn’t kill San Francisco these fires
will be the breaking point. it has become that for me.

~~~
scurvy
What about the fires last year? Or two years ago? Those were worse for SF
proper. It looked like Mars or the end of days 2 years ago.

~~~
novok
No covid... Can't meet people inside or outside now, plus an economy that is
close to starving people. Most places are 3 meals away from a revolution.

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archarios
It seems like they're out of indoor sensors by the way I ordered one and they
printed a shipping label then canceled it.

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snoshy
What is the source for this data?

~~~
stbtrax
They have devices that you can buy and install. Check out their website

