Ozone depletion due to dust release of iodine in the free troposphere

Abstract

Iodine released from dust destroys ozone and indicates a missing atmospheric process in the geochemical iodine cycle.

The gas-phase formation mechanism of iodic acid as an atmospheric aerosol source

“…Field observations and laboratory experiments show that IO 3 − is reduced via iron redox chemistry, H 2 O 2 , nitrite, photosensitized reactions, photolysis and numerous other species (refs. 25,26 and references therein), with the overall effect of recycling iodine to the gas phase. The HIO 3 formation mechanism thus completes a catalytic iodine reaction cycle, by which a single iodine atom can repeatedly form HIO 3 , driving particle formation.…”

“…The photochemical box model builds on the framework described in refs. [22][23][24] and represents state-of-the-art iodine chemistry and HO x chemistry 25,48 . Here, the model is extended by the chamber auxiliary mechanism, which includes losses of gases to the chamber walls and to particles, losses by dilution and the actinic fluxes of the chamber lights.…”

“…This chemical reactivity extends to heterogeneous reactions involving aerosol iodide (I − ) 14,15 and iodate (IO 3 − ) (refs. 25,26 and references therein), which is the thermodynamically most stable form of iodine. The efficient multiphase chemistry of IO 3 − is markedly different from that of inert aerosol sulfate (SO 4 2− ), which accumulates without further chemical conversion until it is scavenged from the atmosphere by wet or dry deposition.…”

Photochemistry of CH3I···(H2O)n Complexes: From CH3I···H2O to CH3I in Interaction with Water Ices and Atmospheric Implications

“…Iodine may also dominate new particle formation and particle growth in coastal area , and in artic . Iodine compounds are naturally released mainly from the oceans either by marine metabolisms (i.e., phytoplankton and micro- and macro-algae) or, in the case of inorganic iodine species (HOI and I 2 ), resulting from the reaction between O 3 and iodide in seawater. − Terrestrial sources of iodine species from arid regions are much less important than marine sources, but have been identified as significant O 3 sinks . The measurements performed during field campaigns showed that photochemical processes occurring within the snowpack may alter the atmospheric composition including the iodocarbon content. , The discovery of primarily methyl iodide (CH 3 I) as potential sources of reactive halogen species during ozone depletion processes , have motivated investigations of photodissociation of CH 3 I adsorbed on ice. ,, There have been extensive experimental and theoretical studies on the photodissociation of CH 3 I in the gas phase − or adsorbed on ice surfaces .…”

Highly Selective Ionic Gel-Based Gas Sensor for Halogenated Volatile Organic Compound Detection: Effect of Dipole–Dipole Interaction

“…X-VOCs containing fluorine (F) and chlorine (Cl) are important raw materials for the synthesis of pesticides, organic solvents, air-conditioning refrigerants, etc., so they are widely applied in the industrial production. However, these X-VOCs are highly volatile and most of them are discharged to the atmospheric environment by disorganized emission, leading to a series of environmental issues including ozone layer destruction, photochemical smog, and global warming. − Besides, X-VOCs are difficult to degrade and can accumulate in the human body, which will cause cancer, genetic mutations, and teratogenicity. , Thus, monitoring the concentration of X-VOCs in air is of great significance for environmental protection and human health. In addition, the identification of X-VOCs also plays a key role in the treatment and recycling of industrial exhaust gases.…”