Being able to see blue skies and white clouds frequently indicates that the air quality in that area is good, right?

There are many colorless harmful gases; P

The most obvious sign of clean, unpolluted air is clear weather and fresh air without any strange odors. It’s not enough to just see blue skies and white clouds; if, under those conditions, there’s a lump of hot cow dung at a distance of 100 millimeters from your eyes, would you still say that the air quality is good?

Your metaphor is apt: lol

Bro, are you being stubborn or are you just using a dumbbell as an example? Air quality isn’t related to a single point; it refers to an entire area. Blue skies and white clouds indicate good air quality, while if there’s any pungent smell, then there must be pollution present, and in that case the weather can’t be clear

【Reply to Floor 7】 Before electric dust removal was in use, the smoke coming from the chimneys was white; one could hide from it. After treatment, the smoke became colorless. Does colorlessness mean there is no smoke? Yes, there is hydrofluoric acid, but it’s invisible. So how can one know when hydrofluoric acid vapor is approaching? It’s simple: just sprinkle some ammonium carbonate on the ground. If hydrofluoric acid is coming, I can see it from a distance. When a dangerous substance is approaching, run away! Guess how I can see colorless hydrofluoric acid gas. The sky was indeed blue, with not a cloud in sight.

Most pollutants are invisible chemicals; it would be too narrow to consider pollution as being caused mainly by dust alone. The majority of pollutants are invisible. Is sulfur dioxide, the most common characteristic pollutant, visible? Just because there is fog, it doesn’t mean there is pollution; that isn’t what pollution is. Fog and sandstorms are natural phenomena that have existed since ancient times, long before the advent of industry. Otherwise, how would the Loess Plateau have come into being? Pollution indicators include dust and specific pollutants, and pollution refers specifically to changes in the environmental condition caused by human activities and excessive exploitation. There are certain criteria for determining pollution; one cannot simply conclude that there is pollution just because there is fog, or that there is no pollution just because the sky is clear.