It serves as a carrier for oxides of nitrogen (NOx) into rural regions and causes ozone formation in the global troposphere.

At lower temperatures, it is stable and can be transported over long distances, providing nitrogen oxides to otherwise unpolluted areas.

Thus, the long-range transport occurs through cold regions of the atmosphere, whereas the decomposition takes place at warmer levels.

[5] Nitrogen oxides from PAN decomposition enhance ozone production in the lower troposphere.

Peak values above 200 μg/m3 have been measured in Los Angeles in the second half of the 20th century (1 ppm of PAN corresponds to 4370 μg/m3).

As an alternative, PAN can also be synthesized in the gas phase via photolysis of acetone and NO2 with a mercury lamp.

Eye irritation from photochemical smog is caused more by PAN and other trace gases than by ozone, which is only sparingly soluble.