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, NO(y), O(3), H(2)O(2), CH(2)O(2), and Cl(2)), while five species show a diurnal pattern of night time maximums (NO(2), HONO, ClNO(2), HNO(3), and N(2)O(5)). Vector autoregression analyses were completed to better understand important species influencing the formation of O(3) and NO(x). For the species studied, r(2) values of predicted versus measured concentrations ranged from 0.82-0.99. 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 O(3) and NO(x) behave as chemical products, reactants (in order of importance) are as follows: H(2)O(2), N(2)O(5), HONO, and ClNO(2).