This is the 10454th most frequent Spanish word.
contaminante
A substance that pollutes or harms the environment.
In this sentence, 'contaminantes' is used as a noun meaning 'pollutants,' referring to substances that pollute the air.
El aire está lleno de contaminantes dañinos.
The air is full of harmful pollutants.
Here, 'contaminantes' is an adjective describing the noun 'gases,' indicating that the gases are causing pollution.
El escape del vehículo emite gases contaminantes.
The vehicle's exhaust emits polluting gases.
In this usage, 'contaminante' is used as an adjective modifying the noun 'impact,' meaning the impact that causes pollution.