This paper presents the results of a study on the effect of moisture content in polylactic acid (PLA) filaments on dust emissions during incremental manufacturing. The tests were conducted in a customised chamber using a standard 3D printer, and Plantower PMS3003 sensors were used to monitor air quality by measuring PM1, PM2.5 and PM10 concentrations. The filament humidity levels tested were 0.18%, 0.61% and 0.83%. The results show that a higher moisture content in the filament significantly increases dust emissions. For dry filaments (0.18% humidity), the average dust emissions ranged from 159 to 378 µg/m. Slightly humid filaments (0.61%) produced higher emissions, with averages between 59 and 905 µg/m, with one outlier reaching up to 1610 µg/m. For very humid filaments (0.83%), the highest average emissions were observed, ranging from 57 to 325 µg/m, along with greater variability (standard deviation up to 198). These findings highlight that increased filament humidity correlates with elevated dust emissions and greater instability in emission levels, raising potential health concerns during 3D printing.