Re: [weewx-user] Purple Air and WeeWx-Purple extension

['John Kline' via weewx-user]

Hi Dan, Please explain how weewx.conf entries could fix the AQI displayed on the PurpleAir website? The AQI you are seeing from my purple extension has the correct pm2_5_cf_1 EPA correction (computed from the average of the two pm2_5_cf_1 readings of the two sensors as well as the current_humidity returned in the purple air reading).  The AQI is calculated using the new EPA AQI formula.  There is nothing more you to do with this number. I was telling you to look at the documents so that you can manually verify the AQI the Purple extension is showing.  I did this because you are questioning if it is correct.  I don’t know any other way for you to know for sure without you going through the steps yourself. If you satisfy yourself that the Purple extension AQI is correct, then you can take this up with PurpleAir as to why it is incorrect on their map.  When I last looked at this, PurpleAir was not giving a date for using the new AQI index. John On Jan 11, 2025, at 8:21 AM, Dan Hinckley <d...@suiattle.org> wrote: Thanks John, did the map settings, and will experiment with your links. I guess there isn't a way to do that correction in the weewx.conf file then? On 10 Jan, 2025, at 13:02, 'John Kline' via weewx-user <weewx-user@googlegroups.com> wrote: The following settings in the purpleair web app will help you, but you can’t get the correct AQI because PurpleAir hasn’t implemented it. If you want to be sure weewx-purple is showing you a correct AQI, you need to take a current reading from the sensor, apply the pm2_5 correction (one of the two links I previously sent) and then use the other link to compute the AQI.  That is what should agree with weewx-purple’s AQI.  AQI will show higher in the green range in weewx-purple since the EPA made that range more stringent in the new calculation (among other changes). <image0.png> On Jan 10, 2025, at 9:24 AM, Dan Hinckley <d...@suiattle.org> wrote: I thought it might be something along those lines. How would I tell is the PA unit is using the new correction? My unit appears here on the PA map, and the page displaying your extension output is here. On 10 Jan, 2025, at 11:51, 'John Kline' via weewx-user <weewx-user@googlegroups.com> wrote: There are two reasons these can differ.  One, the PurpleAir map you are showing is a 2m average while the weewx-purple loop packets are the most recent reading.  Also, the EPA has updated the AQI calculation (see: https://www.epa.gov/system/files/documents/2024-02/pm-naaqs-air-quality-index-fact-sheet.pdf ).  Weewx-purple has been updated with the new AQI calculation while the PurpleAir map has not been. A third reason could be if the PurpleAir map is not using the EPA correction (which corrects pm2_5)—see https://www.epa.gov/sites/default/files/2021-05/documents/toolsresourceswebinar_purpleairsmoke_210519b.pdf .  I cannot tell if this is so from your screenshot. On Jan 10, 2025, at 6:40 AM, Dan Hinckley <d...@suiattle.org> wrote: When I access my PA unit directly, the readings I see are different from the one generated by the John Kline extension. When I check right after WeeWx has generated new files on each loop, direct access to the PA shows this: <Screen Shot 2025-01-10 at 09.37.37.png> And the WeeWx-Purple displays this: <Screen Shot 2025-01-10 at 09.37.56.png> I don't know enough about how the AQI is calculated to know if this discrepancy is normal or is something else. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/C40F997E-F8DC-452D-9D30-3C8307C08AB1%40suiattle.org. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/A5AED7CB-4982-4A46-BD84-8A211646C0E5%40johnkline.com. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/2D6FE60B-105B-4524-86BA-F94D046B70F1%40suiattle.org. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/A2CF2B8A-E028-48C3-AA6E-2A1357F1F3FB%40johnkline.com. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/C6D4D48D-2209-4E6A-AC38-03E96DA18AB8%40suiattle.org. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/EC2EDBD4-6282-4820-8887-8D1921C1F61C%40johnkline.com.