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The origin of atmospheric particulate matter (PM) events in an industrialized mega-city of Central China (Wuhan) was investigated. Wuhan constitutes an ideal case scenario for the study of atmospheric pollution episodes, given that it is representative of densely populated and industrialized Chinese cities. Levels of PM10, NOx and SO2 were evaluated and automatic PM levels were corrected following EU-guidelines, aiming to achieve comparability with results from outside China (Europe and US). This correction evidenced that PM10 levels were underestimated with the automatic instrumentation by 26-38%. This correction is thus essential for the potential use of ambient PM data in epidemiological and climate studies within China and abroad. Several types of peak PM10 events were identified: winter pollution events (daily mean PM10 = 200-350 mu g/m(3)), Asian desert dust events (PM10 increments of 60-70 mu g/m(3) on the daily means) and biomass burning episodes (scarce during the study period). Natural contributions are thus a significant PM source to be taken into account for the evaluation of air quality in the area, the application of daily or annual limit values and the potential assessment of the data from an epidemiological point of view. In addition, the influence of the Wuhan pollution plume was detected in the Mulanhu regional site, which is 40 km far from the city, underlining the large area of influence of atmospheric pollution from Wuhan on the regional-scale. Finally, the results from this work evidence that a detailed knowledge of PM episodes and sources at a given site may be obtained by means of relatively straightforward and economic routine measurements (PM10, NO2, SO2).