Measurements were conducted near Kalamazoo, MI (42.2784°N, 85.6105°W) as part of the 2018 SNow and Atmospheric Chemistry at Kalamazoo (SNACK) campaign.The study was conducted from January 20 to February 24, 2018, at Western Michigan University in Kalamazoo, MI, USA.ClNO2 and N2O5 were measured at 1.5 m above ground level with a chemical ionization mass spectrometer (CIMS, THS Instruments), using iodide I(H2O)- as the reagent ion.PM2.5 chloride and nitrate were measured at 1.8 m above ground level using an an ambient ion monitor-ion chromatography instrument (AIM-IC; model 9000D, URG Corp.)
CIMS has 30 min time resolution, AIM-IC has 3 h time resolution.