emission of ppm

my friend 240sx didn't past the emission ppm, what does that mean? How to fix that?

my friend 240sx didn't past the emission ppm, what does that mean? How to fix that?

PPM means parts per million, there is no PPM test, pollutants are measured in PPM. Find out what what exactly you failed.

What do they measure in CA again? HC's CO's NO's and CO2's ?or do they even measure CO2..

im lived in VA, the paper says it fails the ppm which is the HC
Changing the spark plugs.. Would that help it, cuz sometimes it misfires and u can hear the bang.

HC is hydrocarbons, There is another thread about this just a few threads down, look at that one and see what the came up with in there.