Photochemistry of the polluted troposphere

Journal Article · Fri Apr 09 00:00:00 EST 1976 · Science; (United States)

DOI:https://doi.org/10.1126/science.192.4235.111· OSTI ID:7175994

Finlayson, B J; Pitts, Jr, J N

Historically, the reactions of O/sub 3/ and O(/sup 3/P) in photochemical smog formation have received major attention; however, during the last 5 years, the great importance of other species, such as OH and HO/sub 2/, has been established. Indeed, the hydroxyl radical has now been measured directly in urban air. Determination of the concentration-time profiles of OH under a variety of conditions in simulated and real atmospheres will most certainly greatly enhance our understanding of photooxidation processes occurring in these complex mixtures. Development of sufficiently sensitive detection techniques for other free radical species such as HO/sub 2/ will also prove of great value. Detailed quantitative data on the irradiation of simulated and real polluted atmospheres (even on the stable products) remain sparse; this is especially true for reactions of aromatic hydrocarbons. Furthermore, virtually no quantitative information, necessary for the validation of computer models, is available on the yields of such minor but mechanistically important species as HONO and H/sub 2/O/sub 2/. The complex chemistry of photochemical smog must include heterogeneous as well as homogeneous reactions. In addition, studies of physical and chemical synergisms arising from the introduction of SO/sub 2/ into the HC-NO/sub x/-Ox-UV system are of top priority, since the rate of photooxidation of gaseous SO/sub 2/ to particulate sulfate is greatly enhanced in ambient photochemical smog. Synergisms in these systems may also have important biological consequences. Finally, physical and chemical transformations occurring in the HC-NO/sub x/-Ox-UV system must be far better understood, because such knowledge is a cornerstone of rational, cost-effective air pollution control strategies. However, while this overall research goal is being pursued, we must utilize our existing knowledge and continue to press for an acceptable balance among our needs in energy, economics, and air quality.

• Research Organization: California State Univ., Fullerton
• OSTI ID: 7175994
• Journal Information: Science; (United States), Vol. 192:4235
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
PHOTOCHEMISTRY
HYDROCARBONS
ENVIRONMENTAL EFFECTS
NITROGEN OXIDES
OZONE
SULFUR OXIDES
TROPOSPHERE
POLLUTION
HYDROXYL RADICALS
RADIATION EFFECTS
ULTRAVIOLET RADIATION
CHALCOGENIDES
CHEMISTRY
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
RADICALS
SULFUR COMPOUNDS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)