Carbonyl sulfide (OCS), the most abundant sulfur-containing gas in the atmosphere, is used as a proxy for photosynthesis rate estimation. However, a large missing source of atmospheric OCS has been inferred. Sulfur isotope measurements (³⁴S/³²S ratio and δ³⁴S) on OCS are a feasible tool to distinguish OCS sources from oceanic and anthropogenic emissions. Here we present the latitudinal (north–south) observations of OCS concentration and δ34S within Japan. The observed δ34S of OCS of 9.7 to 14.5‰ reflects source and sink effects. Particularly in winter, latitudinal decreases in δ34S values of OCS were found to be correlated with increases in OCS concentrations, resulting an intercept of (4.7 ± 0.8)‰ in the Keeling plot approach. This result implies the transport of anthropogenic OCS emissions from the Asian continent to the western Pacific by the Asian monsoon outflow. The estimated background δ34S of OCS in eastern Asia is consistent with the δ34S of OCS previously reported in Israel and the Canary Islands, suggesting that the background δ34S of OCS in the Northern Hemisphere ranges from 12.0 to 13.5‰. Our constructed sulfur isotopic mass balance of OCS revealed that anthropogenic sources, not merely oceanic sources, account for much of the missing source of atmospheric OCS.

羰基硫（OCS）是大气中最丰富的含硫气体，被用作光合作用速率估算的代理。但是，已经推断出大气中OCS的大量缺失来源。硫同位素测量（³⁴ S / ³² S比和δ ³⁴ S）上OCS是从海洋和人为排放区分OCS源的可行工具。在这里，我们介绍了OCS浓度的纬度（南北）观测值和δ34日本境内的S。观察到的δ34OCS的S为9.7至14.5‰，反映了源和汇效应。特别是在冬季，纬度在δ34发现OCS的S值与OCS浓度的增加相关，从而在Keeling图法中截获了（4.7±0.8）‰。这一结果表明，亚洲人的季风外流将人为的OCS排放物从亚洲大陆输送到了西太平洋。估计背景δ34东亚OCS的S与 δ34OCS先前曾在以色列和加那利群岛报道过，这表明背景 δ34北半球OCS的S值范围为12.0至13.5‰。我们构建的OCS的硫同位素质量平衡表明，人为来源而不是海洋来源占了大气OCS缺少的大部分来源。