Pencemaran udara merupakan salah satu permasalahan lingkungan yang berdampak luas terhadap kesehatan manusia, ekosistem, dan perubahan iklim. Pencemaran ini disebabkan oleh berbagai polutan seperti sulfur dioksida (SO2) dan nitrogen dioksida (NO2) yang dominan disebabkan oleh aktivitas industri dan pembakaran bahan bakar kendaraan bermotor. Oleh karena itu perlu dilakukan pemantauan kualitas udara agar bisa menentukan strategi dalam menjaga stabilitas kualitas udara. Penelitian ini untuk mengetahui tingkat kualitas udara di Kabupaten Mojokerto dan mekanisme pemantauan kualitas udara dengan metode passive sampler. Pemantauan dilakukan di 4 titik yang mewakili kondisi wilayah perkantoran, pemukiman, industri, dan transportasi. Titik pemantauan kualitas udara berlokasi di kawasan pemukiman, perkantoran, industri dan padat tranasportasi Kabupaten Mojokerto. Hasil dari pemantauan kualitas udara adalah rata-rata konsentrasi SO2 dan NO2 Kab. Mojokerto masih berada dibawah baku mutu sesuai dengan Permen LHK no 27 Tahun 2021. Air pollution is one of the environmental issues that has wide-ranging impacts on human health, ecosystems, and climate change. This pollution is caused by various pollutants such as sulfur dioxide (SO2) and nitrogen dioxide (NO2), which are predominantly generated by industrial activities and motor vehicle fuel combustion. Therefore, air quality monitoring is necessary to determine strategies for maintaining air quality stability. This research aims to determine the air quality level in Mojokerto Regency, the air quality monitoring mechanism using the passive sampler method, and the efforts undertaken to maintain air quality stability in Mojokerto Regency. Monitoring was conducted at four locations representing office areas, residential areas, industrial areas, and transportation zones. The air quality monitoring points were in residential areas, office areas, and dense transportation areas in Mojokerto Regency. The results of the air quality monitoring showed that the average concentrations of SO2 and NO2 in Mojokerto Regency were still below the quality standards stipulated by the Minister of Environment and Forestry Regulation No. 27 of 2021.