Abstract
A 190 m3 outdoor smog chamber was used to study partitioning and photochemistry of 1- and 2-nitronaphthalene. The partitioning experiments were conducted at night. The photochemical formation of nitronaphthalenes was studied using a mixture of naphthalene, propylene, NOx and diesel particles. The buildup in the gas phase was followed by a rapid photolysis of 1-nitronaphthalene, whereas 2-nitronaphthalene decayed more slowly.
In a separate daytime experiment, photolysis rate constants were determined relative to kNO2 to be 0.07xkNO2 and 0.005×kNO2 for 1- and 2-nitronaphthalene, respectively. Our results confirm that gas-phase photolysis is the major degradation pathway for 1-nitronaphthalene, whereas for 2-nitronaphthalene other pathways may also be important. Evidence is provided that partitioning equilibrium is maintained even when the gas-phase components are decaying rapidly. A nitronaphthalene mechanism has been successfully implemented in the photochemical smog mechanism, Carbon Bond-4.