Seasonal persistence of the nitrogen oxides production in Mexico City

Abstract This study investigates the seasonal influence on the nitrogen oxide NO x pollution records at four monitoring sites in Mexico City from 2010 to 2018. The analysis employs the second-order structure function to examine the trends in NO x concentration fluctuations. The findings reveal that the fluctuations follow a power law pattern characterized by Hurst exponents, predominantly in the statistical persistence regime, with a scaling range spanning three orders of magnitude. Specifically, the autumn period exhibits fluctuations with an exponent of $$\overline{H}=0.72$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mover> <mml:mi>H</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>=</mml:mo> <mml:mn>0.72</mml:mn> </mml:mrow> </mml:math> , indicating relatively smaller fluctuations compared to other seasons, but with the potential for NO x concentrations to surpass those in other periods. In contrast, for spring, summer, and winter, the fluctuations are characterized by exponents of $$\overline{H}=0.59$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mover> <mml:mi>H</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>=</mml:mo> <mml:mn>0.59</mml:mn> </mml:mrow> </mml:math> , $$\overline{H}=0.61$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mover> <mml:mi>H</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>=</mml:mo> <mml:mn>0.61</mml:mn> </mml:mrow> </mml:math> , and $$\overline{H}=0.62$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mover> <mml:mi>H</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>=</mml:mo> <mml:mn>0.62</mml:mn> </mml:mrow> </mml:math> , respectively, demonstrating greater fluctuations with lower NO x concentrations compared to autumn. These results are consistent with various studies conducted worldwide. Additionally, a negative correlation between NO x and ozone ( O 3 ) has been established during the winter season, as NO x and O 3 fluctuations display persistent and anti-persistent behavior, respectively.