It is evident that urban ambient air pollution has disproportionately negative effect on socioeconomically disadvantaged communities living in downgraded urban environment. However, the factors that must be systematically considered when assessing population exposure inequalities have not been thoroughly addressed from an urban informatics perspective. In this paper a theoretical framework is proposed with respect to identifying the necessary factors for assessing inequalities in exposure to urban air pollution by means of urban informatics methods. A five -domain factor classification for assessing population’s exposure to ambient urban air pollution is proposed, with use of urban informatics approaches and context. The five-domain classification is organized in: i) the source of pollution and its dispersion characteristics, (ii) the dynamics of population exposure, (iii) socioeconomic and demographic vulnerability, (iv) urban morphology and urban landscape, and (v) data infrastructure and methodological factors. Each domain is thoroughly examined by taking into consideration its significance, constituent factors, data requirements, analytical methodologies and evaluation. The proposed framework provides a systematic reference for urban informatics system design, with particular emphasis on equitable sensor deployment and integration of cadastral, planning, and socioeconomic data into environmental monitoring.