I don't think the MQ135 can do what you are asking. It basically shows a value representing air quality and not individual pollutants. Use the datasheet if you want to understand what it reports if calibrated properly.
If you're working with a naked sensor (no breakout board or printed circuit board), then you can try this:
Read the datasheet to make sense of the given wiring diagram.
Then code your sketch as follows:
int sensorPin = A0;
int sensorValue = 0;
Serial.begin(9600); // sets the serial port to 9600
sensorvalue = analogRead(sensorPin);
Serial.println(value, DEC); // print decimal value
delay(100); // wait at least 100 milliseconds