meteohub.de

Hi

From my understanding (and I may be wrong) the Air Quality Index is not a number

It is a category based on the values of the 2.5 and 10 particle concentration so if a number is displayed as an index that is incorrect

Regards

Graham

Hi Brian,

The latest AQI update looks great and clarifies the reported values. The VOC remains experimental (with Purple Air) and I need to check the hardware - I may have obstructed the airflow around the chip when I added it a few months ago, rendering higher values.

I plan on using the Airlink as an indoor device, so the raw values are fine with me. As you indicated, the main value is to check any relative changes in the reported data.

Purple Air has some interesting information relative to conversions that can be seen at any of its sensor sites. It is not definitive, but does show some of the variables.

Here is an example of mine.

https://www.purpleair.com/map?opt=1/mAQ ... /-78.93869

Many thanks,

Chuck

Ok Chuck we can tweak the VOC scale as appropriate and more relative based on your output which I did earlier , for reference just use the AIRLINK for what you intended for ,once you get into the path of comparing one and against the other 24/7 you end up not using it for it was intended for just, creates so much confusion, uncertainty , trust in what you bought and so on .. hence you see a lot confusion going on with AQ .. FWIW im sticking to the purple air script and layout. ill continue to push changes to GITHUB as and when .

i dont take anything as criticism im too thick skinned to be offended ... but i do like to read and listen to constructive ideas and criticism, all ideas have a value just have to ween out the ones that are not all about ones own backyard and use the ones that are valid for everyone as its easier to move forward if everyone is on the same boat its far easier to resolve any issues that can arise either by my mistakes or unseen scenarios that can arise and trust me they do ask Chuck but their easy to resolve in a short period because 90% of the time i can replicate it if we are on the same boat.. with AQI as you can see its all rather confusing as to what one wants and what is expected with AQI at present , i do t recall this at anytime in the past when AQI data was just pulled from an api . at present personally ill just tweak the purple air script as it now includes voc and leave the rest until i can establish a best approach that suits all . dont ever feel shy of dishing out criticism along as its constructive , relevant then its all beneficial .

luftdaten not every sensor has pm 2.5 has i found out earlier last week , also with luftdaten pm 2.5 is not always the primary particle matter i have seen pm10 appear as the primary particle so you can see the template now needs an option to determine what is being used as a primary particle... nothing is ever as easy as just do that just do this unfortunately..brian

Brian,
Okay, I'll take note of that. Changed it for me now (are only two tiny changes in the php file), I'm satisfied with that.

Hi Brian,

Regarding the Purple Air VOC, I did some research on the BME680 Bosch sensor that is used. Keeping it simple (3 colors) - it looks like their scale would match up like this:

if($aqiweather["voc"] >=201){ echo "<red>".$aqiweather["voc"]."</red>";}
else if($aqiweather["voc"] >=101){ echo "<yellow>".$aqiweather["voc"]."</yellow>";}
else if($aqiweather["voc"] >0){ echo "<green>".$aqiweather["voc"]."</green>";}

I made an adjustment in my hardware - the sensor chip placement was restricting airflow and inflating the values.

Best wishes,

Chuck

ok chuck all done as per your color code ..have a good evening..brian

a work in progress for Davis Airlink or Purple Air popups please note work in progress a release including Lufdaten/MB assigned to position 175 support will come when this is found to be stable/manageable enough across all user configuration possibilities .

Hi Brian

That looks really good - thanks for all your hard work

I just have a question though -what does the number in the Air Quality Index actually mean - it doesnt seem to bear any relation to the PM values

Kind Regards

Graham

as it as always been since day one in 2018 for purple air AQI US !!! charts are dummy data as ive only just started collecting 10 min data for charts . as above work in progress with a few beta testers to get the right balance.

Hi guys,

The AQI data point is confusing. Some devices use the amount of PM2.5 particulates over a 10 minute period some use over 1 hour or more. Here is a nice calculator that shows the relationship between PM2.5 and AQI for US EPA.

https://www.airnow.gov/aqi/aqi-calculat ... entration/

Chuck

Hi Brian,

I see you are working on ID's and charts. Those will be great additions. . As usual, Chrome and Firefox want to create a slight alignment issue. I also have a few screen shots to show the scaling on the charts, before and after, for your info.

Before
After
Take care,

Chuck

Hi

I agree - from my point of view I would rather see the text GOOD UNHEALthy etc - the number is meaningless

But I am happy to accept the majority view

Regards

Graham

ok chuck just pushed ff alignment and column bar width for chart .

graham its logical to use phrases but to me its one less thing to worry about in terms of translations at present , first thing establish an happy medium make it universal then add on the extras but chuck highlights different practices , use of actual figure , average period figure and so on ive seen all these and yet to fathom out how to determine what one is actually using..
im sure in time all will come good..