Based on experiments, it was also found that sulfur dioxide gas adheres to the surfaces of kosa particles, with kosa particles working as a catalyst, and that the ammonium sulfate, much included in the air of major cities in China, adheres to kosa in high-humidity conditions and becomes calcium sulphate (gypsum) through the process in which calcium in kosa reacts with ammonia.
また実験により、黄砂の粒子が触媒となって、二酸化硫黄ガスが黄砂粒子の表面に吸着されて反応し硫酸イオンになることや、中国主要都市の大気に多く含まれる硫酸アンモニウムが、湿度が高いときに黄砂に吸着され、黄砂中のカルシウムがアンモニアと置換反応して硫酸カルシウム（石膏）になることも分かった。