what are the main compounds of air? what are toxic gases in air? how they are formed?

Dear Student,

Air is a mixture of many gases, water vapour, dust particles, and smoke. Nitrogen constitutes about 78% of air, next to nitrogen, oxygen is the most abundant gas constituting around 21% of the air. The rest 1% of the air contains carbon dioxide, argon, water vapour, and dust particles.

Hope it is clear to you now,

Cheers!!