This paper provides a cost effective and generic solution for urban air pollution monitoring using existing computing resources and infrastructure. The design has been modularised into three subsystems — the Data Acquisition System (DAS), Data Transmission System (DTS), and the Data Collation System (DCS). The DAS is composed of ground-based sensing equipment attached to the PCs, of citizen-volunteers geographically spread out in a city, connected to a central server via the internet. The devices periodically send snap-shots of urban environmental conditions of their respective localities to the central server using the DTS. Here, the DCS seamlessly aggregates received data to build a comprehensive database (DB) of the history of environmental conditions in a given urban setting and allows internet users to view analyses run on that data.