Chapter 5, Problem 5.3PAE

Interpretation Introduction

Interpretation:

The reason for the decrease in NO concentration at noon should be explained.

Concept Introduction:

• The chemical reactions that lead to the formation of smog are:

  $\begin{array}{l}1.N{O}_2+h\gamma (Sunlight)\to NO+O\\ 2.O+O_2\to O_3\\ 3.O_3+NO\to N{O}_2+O_2\\ 4.N{O}_2+R(VOCs)\to PAN\\ 5.NO+R{O}_X\to N{O}_2+Other\mathrm{Pr}oducts\end{array}$

• Nitrogen dioxide breaks down in presence of sunlight to give Oxygen radical which further reacts with atmospheric oxygen to produce Ozone in the low atmospheric level. Ozone consumed by NO to produce NO₂ which further reacts with hydrocarbon of the volatile organic compounds (VOCs) to produce toxic compounds like Peroxyacetyl nitrate (PAN). Oxygenated organic and inorganic compounds (ROx) also react with nitric oxide to produce more nitrogen oxides.