4:14 know that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming oxides of nitrogen

When fuels are burned in vehicle engines, high temperatures are reached.

At these high temperatures nitrogen and oxygen from the air react to produce nitrogen oxides:

          nitrogen          +          oxygen        →          nitrogen oxides

eg

          N2 (g)              +          O2 (g)          →          2NO (g)

In the atmosphere these nitrogen oxides can combine with water to produce nitric acid (HNO3).