Several countries have mixed industrial-residential zones, favoured by social dynamics and the absence of land-use planning policies. Identifying the contributions of different emission sources to ambient pollution levels helps to guide air quality management efforts. Although more importance is given to stationary sources, recent studies have shown the strong contribution of mobile sources, the control of which is more complex. In this context, it is proposed to develop a simple and indirect methodology to identify the emission contributions of mobile sources to ambient particulate matter in industrial-residential areas, based on existing monitoring networks designed for stationary sources and inventories of these sources and the AERMOD View® modelling system. Mobile sources are usually neglected in industrial areas, but here they are presented as a relevant source to the contributions of ambient levels of particulate matter below 10 micrometres (PM10) due to the expansion of residential areas over industrial areas. The contribution from stationary sources at each of the six receptor sites studied varies between 9.6% and 32.2%, with the exception of one of the receptors, which reaches 99.3% due to its proximity to the main stationary source of emissions. When comparing the maximum controlled values at the receptors with the guideline levels suggested by the World Health Organization (WHO), the latter are exceeded for both exposure periods. However, none of the values estimated with AERMOD View at the receptors exceed the WHO guideline levels. This shows that stationary sources are not the most relevant.