A system and method for automated analysis of a membrane filter obtained from an air quality monitoring apparatus used for sampling airborne respirable fibres such as asbestos and synthetic mineral fibres is described. The membrane filter is loaded on a robotic XY stage of a digital phase contrast microscope which is used to capture at least one magnified phase contrast image at each of 20 or more sample locations located across the filter member. The magnified phase contrast images are analysed using a computer vision method, including deep learning classifier based methods, to identify and count the number of fibres in the field of view. When at least 100 respirable fibre are counted or images collected from at least 100 sample locations, the total number of counted fibres is reported. 112 ~ Captu~re full image of Movesso exvt Anis pit 124-~~~b imGesnVusb Analr
