Abstract: Indoor particle and lacquer pieces were collected in Emperor Qin’s Terra-cotta Warriors and Horses Museum. The SEM-EDX analysis for long-term (LTDF, over 10 years), short-term (STDF, ～ 0.5 year) dust fall, suspended atmospheric particles (SPM), and lacquer pieces (LP) were preformed. The diameters of S-containing SPM, STDF, and LTDF ranged 0.9～22.8μm, 1.0～29.0μm 1.2～37.7μm, respectively. Those impure S-containing particles were mostly gypsum with an internally mixed state with clay or quartz. Small floccules of gypsum were much more frequently observed in dust fall than in suspended particles, which implied a progressive chemical reaction between continuous dust fall and atmospheric sulfur dioxide. Crystals of calcium sulfate were also found in-situ growing near pits and cracks on the surface of lacquer pieces, which reveals that acid chemical reaction between sulfur dioxide and lacquer material or dust fall particles was one of the reasons of the formation of erosion pits and cracks on the surface of lacquer pieces.

Key words: Emperor Qin’s Terra-cotta Warriors and Horses Museum, indoor particle, S-containing particle, SEM-EDX