Obtain product quality for the (Sentinel-5P OFFL NO2: Offline Nitrogen Dioxide) mean image

Question

I am unable to obtain this property of image:

PRODUCT_QUALITY STRING - (Indicator) that specifies whether the product quality is degraded or not. Allowed values are "Degraded" and "Nominal".

https://code.earthengine.google.com/12d44579494aab219bdd92bb45de72b3

Answer 1

As I said before, you need the collection before applying mean. Then, you can convert it into a table, selecting the PRODUCT_QUALITY metadata. Now, you can check this metadata either by printing it or by exporting it into csv.

//filtering image collection without calculating the mean value
var dongguan_area = ee.ImageCollection("COPERNICUS/S5P/OFFL/L3_NO2")  //importing image collection dataset
  .filterBounds(area_dongguan)      //filtering region of interest
  .filterDate('2019-10-01','2019-10-24')     //filtering date 
  .select('NO2_column_number_density')  //selecting band
  //.mean();   //obtaining mean a/c to filters

// convert image collection into a table
var pq = ee.FeatureCollection(dongguan_area).select(['PRODUCT_QUALITY']);

// print table
print('PRODUCT QUALITY', pq);

// Export to csv
Export.table.toDrive({
  collection: pq,
  description: 'pq',
  fileFormat: 'csv'
});