Recently, the issues of air pollutants have become a major topic that is currently being debated among researchers and authority as it give negative impacts to the environment. This paper will discuss thoroughly on techniques that are currently being applied in monitoring air pollution. Techniques that are quite familiar in monitoring air pollution are such as the absorption spectroscopy technique, ozone monitoring instrument (OMI) and solid state gas sensor. Throughout this paper, the equipment used and the outcome from a number of methods will be reviewed. For future improvements, a new sensor for air monitoring will be proposed which is envisaged capable to detect ultrafine particles (UFPs) (i.e. with a diameter less than 100 nm).