Time series analysis of wintertime O3 and NOx formation using vector autoregressions. (1st December 2019)

• Record Type: Journal Article
• Authors: Olson, David A.; Riedel, Theran P.; Long, Russell; Offenberg, John H.; Lewandowski, Michael; Kleindienst, Tadeusz E.
• Is Part Of: Atmospheric environment. Volume 218(2019)
• Publication Date: 2019-12-01
• Subjects: Ozone formation -- Hydrogen peroxide -- Nitrous acid -- Dinitrogen pentoxide -- Nitryl chloride; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2019.116988
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: Concentrations of 11 species are reported from continuous measurements taken during a wintertime field study in Utah. Time series data for measured species generally displayed strong diurnal patterns. Six species show a diurnal pattern of daytime maximums (NO, NOy, O3, H2 O2, CH2 O2, and Cl2 ), while five species show a diurnal pattern of night time maximums (NO2, HONO, ClNO2, HNO3, and N2 O5 ). Vector autoregression analyses were completed to better understand important species influencing the formation of O3 and NOx . For the species studied, r 2 values of predicted versus measured concentrations ranged from 0.82 to 0.99. Fitting parameters for the autoregressive matrix, Π, indicated the importance of species precursors. In addition, values of fitting parameters for Π were relatively insensitive to data size, with variations generally <10%. Variable causation was quantified using the Granger causation method. Assuming O3 and NOx behave as chemical products, reactants (in order of importance) are as follows: H2 O2, N2 O5, HONO, and ClNO2 . Highlights: Measurements of 11 species were taken during a wintertime field study in Utah. A high-resolution time-of-flight chemical ionization mass spectrometer was used. Vector autoregression analyses were completed for all species. Important precursor species included H2 O2, N2 O5, HONO, and ClNO2 .