Infrared solar spectra recorded between July 1991 to March 1992 and November 2002 with the Fourier transform spectrometer on Kitt Peak (31.9°N latitude, 111.6°W longitude, 2.09 km altitude) have been analyzed to retrieve stratospheric columns of HNO₃, NO, and NO₂. The measurements cover a decade time span following the June 1991 Mount Pinatubo volcanic eruption and were recorded typically at 0.01 cm⁻¹ spectral resolution. The measured HNO₃ stratospheric column shows a 20% decline from 9.16 × 10¹⁵ molecules cm⁻² from the first observation in March 1992 to 7.40 × 10¹⁵ molecules cm⁻² at the start of 1996 reaching a broad minimum of 6.95 × 10¹⁵ molecules cm⁻² thereafter. Normalized daytime NO and NO₂ stratospheric column trends for the full post-Pinatubo eruption time period equal (+1.56 ± 0.45)% yr⁻¹, 1 sigma, and (+0.52 ± 0.32)% yr⁻¹, 1 sigma, respectively. The long-term trends are superimposed on seasonal cycles with ∼10% relative amplitudes with respect to mean values, winter maxima for HNO₃ and summer maxima for NO and NO₂. The measurements have been compared with two-dimensional model calculations utilizing version 6.1 Stratospheric Aerosol and Gas Experiment (SAGE) II sulfate aerosol surface area density measurements through 1999 and extended to the end of the time series by repeating the 1999 values. The model-calculated HNO₃, NO, and NO₂ stratospheric column time series agree with the measurements to within ∼8% after taking into account the vertical sensitivity of the ground-based measurements. The consistency between the measured and model-calculated stratospheric time series confirms the decreased impact on stratospheric reactive nitrogen chemistry of the key heterogeneous reaction that converts reactive nitrogen to its less active reservoir form as the lower-stratospheric aerosol surface area density declined by a factor of ∼20 after the eruption maximum.