Verification of fugitive emission of aeolian river dust and impact on air quality in central western Taiwan by observed evidence and simulation

Abstract Taiwan's rivers dry during the winter, exposing large areas of river bed and leading to airborne aeolian river dust. This study used PM10 and windspeed data taken from monitoring stations local to the Zhuoshui River (the river with the largest exposed area in Taiwan) to investigate the relationship between airborne river dust and air quality, and subsequently to estimate river dust emissions. During river dust events, PM10 concentrations were significantly and positively correlated with wind speeds exceeding 5 m/s (the critical wind speed). FPG Lunbei station, located downwind (south of the river) and the closest station to the river, recorded an average hourly PM10 concentration of 189 ± 193 μg/m3 an average correlation coefficient (r) of 0.94 between hourly PM10 concentration and average hourly wind speed, an average annual dust occurrence rate of 15%, and a maximum PM10 concentration exceeding 1000 μg/m3. PM2.5 increased with PM10, albeit at a disproportional rate. When hourly PM10 concentration exceeded 200 μg/m3, most of the particulates in the dust were coarse particulates (PM2.5–10). An hourly PM2.5/PM10 ratio of