The project MOBILAB aims at the development of a mobile continuous urban air pollution monitoring system, capable of collecting and analyzing pollution data in real-time mode. Hazardous airborne pollutants (emissions) consist of a large group of potentially toxic compounds emitted from a variety of mobile and stationary sources. Among them, in urban areas, automotive emissions are claimed to have a major contribution. Although engine emissions per vehicle have been reduced for twenty years with technical developments in the fields of engine, after-treatment technologies and fuels (i.e. catalytic converters, diesel particulate filters, unleaded gasoline, low fuel sulphur content the urban air pollution problem still exists in many cities around the world. Forthcoming European emission regulations (EURO V) will require further development of new complex technologies to reach low emissions standards (Particulate Matter, Nitrogen Oxides, Hydrocarbons and Carbon Monoxide). Real vehicle drive assessment of such technologies offers significant advantages in the development phase of novel emission reduction systems as valuable conclusions can be extracted regarding their performance and durability. The project aims to the development of a mobile laboratory with two-fold capabilities: On the one hand it will be able to monitor urban air pollution by measuring the concentration of the major gaseous and particulate pollutants concentration in the urban environment and on the other hand it will be able to act as a mobile automotive emissions reduction systems test center (i.e. able to measure the engine exhaust gaseous and particulate pollutants concentration) for the assessment of future exhaust after-treatment technologies under real drive conditions. A committed van-type vehicle will be equipped with all instruments (HCs, CO, NOx analyzers, particulate matter (PM) sensors, PM concentration and size distribution analyzers etc). The multinational partner consortium consists of three organizations with extensive experience in emissions and emissions measurements and the development and assessment of innovative engine exhaust after-treatment technologies. The project will take advantage of recent developments made in the context of European research projects in which the partners have participated e.g. advances in the of emission measurements technologies, real-time particulate sensors etc. Initially the measurement protocols of each pollutant will be defined. The necessary measuring instruments will be defined and acquired/developed. Necessary arrangements will be made to facilitate the measuring instruments operation on vehicle under on-road conditions. The mobile laboratory will then be calibrated against state-of-the-art laboratory instruments and its performance will be evaluated. It will be then ready to be used for field measurements for either urban pollution monitoring or the testing of innovative exhaust after-treatment systems. There are certain advantages in the concept of the creation of a pollution map via this mobile laboratory as fixed monitoring stations are usually most costly and the possibility of introducing them in the desired areas does not always exist. Moreover by tracking the position of the vehicle (e.g. via a GPS system) the pollution map created will be near-real time in contrast to the reports over standard time intervals of the fixed air pollution monitoring stations. As far as the capability of the mobile laboratory to test the engine out emissions of a vehicle is concerned, the advantage of it over fixed testing stations is more than obvious. Direct beneficiaries of the project outcome will be the municipal and traffic control authorities who based on the information the mobile laboratory, will create on the pollution situation will be able to take corrective measures to avoid undesired air pollution incidents. In addition, this mobile laboratory will benefit the owner organizations with the ability for real-life testing and evaluation of exhaust after-treatment technologies under development.