Polycyclic aromatic hydrocarbons in the atmosphere: monitoring, sources, sinks and fate. II: Sinks and fate.
This paper reviews the transformation processes that polycyclic aromatic hydrocarbons (PAHs) undergo in the atmosphere. These processes can take place both in the gas phase and in the particulate/aerosol one. Among the gas-phase processes, the most important ones are the daytime reaction with *OH and the nighttime reaction with *NO3. The relative importance of the two processes depends on the particular PAH molecule. For instance, gaseous naphthalene is mainly removed from the atmosphere upon reaction with *OH, while gaseous phenanthrene is mainly removed by reaction with *NO3. Oxy-, hydroxy-, and nitro-PAHs are the main transformation intermediates. Reaction with ozone and photolysis play a secondary role in the transformation of gaseous PAHs. The particle-associated processes are usually slower than the gas-phase ones, thus the gas-phase PAHs usually have shorter atmospheric lifetimes than those found on particulate. Due to the higher residence time on particulate when compared with the gas phase, direct or assisted photolysis plays a relevant role in the transformation of particle-associated PAHs. Among the other processes taking place in the condensed phase, nitration plays a very important role due to the health impact of nitro-PAHs, some of them being the most powerful mutagens found so far in atmospheric particulate extracts.
Vione
Davide
D
Dipartimento di Chimica Analitica, Università degli Studi di Torino, Via Pietro Giuria 5, 10125 Torino, Italy. davide.vione@unito.it
Barra
Silvia
S
De Gennaro
Gianluigi
G
De Rienzo
Massimo
M
Gilardoni
Stefania
S
Perrone
Maria Grazia
MG
Pozzoli
Luca
L
D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring; D017665:Hydroxyl Radical / Q000737:chemistry; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010316:Particle Size; D010782:Photolysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000737:chemistry*
D000336:Aerosols; D000393:Air Pollutants; D016877:Oxidants; D011084:Polycyclic Aromatic Hydrocarbons; D017665:Hydroxyl Radical