# Aerosol optical depth (AOD) and particulate matter (PM10, PM2.5) at forecast step 0: all values are zero **URL:** \ **Category:** CAMS - Datasets and Usage\ **Tags:** cams, cams\_global\_forecast\ **Created:** [24 September 2019 14:49 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556 "2019-09-24T14:49:37Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Michela](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/898d66/32.png) [@Michela](https://forum.ecmwf.int/u/Michela)\ **Post date:** [24 September 2019 14:49 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/1 "2019-09-24T14:49:37Z")
I downloaded data from the [CAMS Global near-real-time archive](http://apps.ecmwf.int/datasets/data/cams-nrealtime/levtype=sfc/) or other CAMS Global products, and the aerosol optical depth (AOD) and particulate matter (PM10, PM2.5) values are all zero at forecast step 0. Why does this happen? ---
**Author:** ![Antje\_Inness](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/a/eb8c5e/32.png) [@Antje\_Inness](https://forum.ecmwf.int/u/Antje_Inness)\ **Post date:** [26 September 2019 12:47 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/2 "2019-09-26T12:47:20Z")
This is a known issue. It is due to a bug that caused AOD and PM to not be computed for Step 0 (analysis time), and zeros were stored instead. **Affected Species** are AOD and PM, and only at forecast step 0. Subsequent steps are computed as designed. **Affected datasets** are the CAMS Global Near-Real-Time forecasts, the CAMS interim Reanalysis (CAMSiRA), and potentially other CAMS global datasets. **Fixes:** For AOD a fix was implemented, and since 24 January 2017 AOD at forecast step 0 is available. For PM a fix will be implemented in 2017. **Workaround:** Download data with forecast steps other than 0. For example, you need data for validity time 2015-01-01, 00:00. In this case do not download data for 2015-01-01, 00:00, step 0 (base time + 0 hours forecast). Instead, download for example data for 2014-12-13, 12:00, step 12 (base time + 12 hours forecast), which also results in a validity time 2015-01-01, 00:00. For more information on system changes please see [https://atmosphere.copernicus.eu/changes-cams-global-production-system](https://atmosphere.copernicus.eu/changes-cams-global-production-system) ---
**Author:** ![Lucas\_Couto](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/l/8e8cbc/32.png) [@Lucas\_Couto](https://forum.ecmwf.int/u/Lucas_Couto)\ **Post date:** [26 September 2020 23:17 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/3 "2020-09-26T23:17:52Z")
Hello Michela I am facing the same problem, when I open this same data (downloaded fromCAMS  near\_real\_time\_archive and CAMS reanalysis) my values are all zero when I open the data in Panoply ... Did you solve this problem? Do you have any tips? I tried to change the steps but the errors continue. ---
**Author:** ![Mariana\_Dias](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/f08c70/32.png) [@Mariana\_Dias](https://forum.ecmwf.int/u/Mariana_Dias)\ **Post date:** [23 September 2022 20:12 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/4 "2022-09-23T20:12:45Z")
Hello [Antje Inness](https://confluence.ecmwf.int/display/~std),  ``` I'm trying to find the pm2.5 values ​​in the file provided by CAMS, GFAS, as well as Michela, I couldn't extract the information. In my case, I'm not looking for hourly data, but daily. And the data values are all zero. Can you help me? ``` ---
**Author:** ![Antje\_Inness](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/a/eb8c5e/32.png) [@Antje\_Inness](https://forum.ecmwf.int/u/Antje_Inness)\ **Post date:** [26 September 2022 07:41 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/5 "2022-09-26T07:41:06Z")
Hi Mariana, Could you please go through the ecmwf support portal [https://www.ecmwf.int/en/support](https://www.ecmwf.int/en/support) and raise an issue there. Thanks, Antje ---
**Author:** ![Chloe\_Tarlen](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/c/d78d45/32.png) [@Chloe\_Tarlen](https://forum.ecmwf.int/u/Chloe_Tarlen)\ **Post date:** [18 October 2023 16:48 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/6 "2023-10-18T16:48:46Z")
Hello! I'm actually having this same issue. Not sure why but all of my PM10 values are 0 in Panoply. Any updates with this bug fix? ---
**Author:** ![Mariana\_Dias](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/m/f08c70/32.png) [@Mariana\_Dias](https://forum.ecmwf.int/u/Mariana_Dias)\ **Post date:** [26 September 2022 16:45 UTC](https://forum.ecmwf.int/t/aerosol-optical-depth-aod-and-particulate-matter-pm10-pm2-5-at-forecast-step-0-all-values-are-zero/1556/7 "2022-09-26T16:45:22Z")
Thanks for your answer Antje! Unfortunatelly the the errors continue. #### [Lucas Couto](https://confluence.ecmwf.int/display/~doutorado.lucas.couto@gmail.com) can you help me?