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'
});
Dongguan_area
? In that case, after usingmean()
at the beginning of the code, you lost the properties, because you are converting the collection into a single image (a mean composite). This composite does not have properties unless you set them.