https://goldenmidas.net/story.php?title=error-the-requested-url-could-not-be-retrieved-154 Pollutants will be categorized as main or secondary. Secondary pollutants are in a roundabout way emitted from sources, however as a substitute type within the ambiance from major pollutants (additionally referred to as "precursors"). Sat, 23 Jan 2021 05:21:44 UTC en