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Titre du document / Document title

Photochemical oxidant air pollution : A historical perspective

Auteur(s) / Author(s)

DAVIDSON A. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Davidson and Associates Environmental Consulting, 4814 Somerset Drive SE, Bellevue, Washington 98006, ETATS-UNIS

Résumé / Abstract

Photochemical smog first came into prominence in July 1943, in Los Angeles. In 1947, the Los Angeles County Air Pollution Control District was formed to deal with the growing smog problem, which was caused by a combination of poor atmospheric ventilation, strong solar radiation, confining topography, and generally uncontrolled pollutant emissions. In the early to mid 1950s, the basis of photochemical smog theory was set forth by Professor Arie J. Haagen-Smit of the California Institute of Technology, who concluded that ozone and other photochemical oxidants were not emitted directly, but were formed in the atmosphere when precursor emissions of oxides of nitrogen and hydrocarbons reacted with each other in the presence of sunlight. Beginning in 1959, the State of California moved to control vehicle emissions, passing a series of acts which culminated in the formation of the Califomia Air Resources Board in 1967. On the federal level, congress passed the first Clean Air Act in 1963, with subsequent major amendments added in the 1970 Act (which also established the Environmental Protection Agency), and the 1990 Act. Although some controls had been required on motor vehicles in the 1960s, it was not until 1975 that the first catalytic converters, designed to reduce emissions of hydrocarbons and carbon monoxide appeared, with the three way catalyst (to also control oxides of nitrogen) being introduced on 1981 model vehicles. In 1976, recognizing the regional nature of photochemical smog, the four local agencies of the Greater Los Angeles region combined to form the South Coast Air Quality Management District. In the Los Angeles region, ozone concentrations showed a moderate overall decline from the late 1950s to the late 1970s, and have declined substantially from the late 1970s until the present time, even in the face of large increases in population and vehicle miles traveled. Ozone trends for the period 1986-95 are also presented for several major cities in the United States. Also discussed are current trends to incorporate market forces in the control of pollutant emissions, and the future outlook for reducing pollutant emissions still further by a combination of technological and educational means.

Revue / Journal Title

Studies in environmental science    ISSN  0166-1116 

Source / Source

Congrès
Air pollution in the 21st century : priority issues and policy
Facing the air pollution agenda for the 21st century. US-Dutch symposium No5 , PAYS-BAS (sd)
1998  , vol. 72, pp. 393-405[Note(s) : XI, 1100 p., ] (18 ref.) ISBN 0-444-82799-4 ;  Illustration : Illustration ;

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Amsterdam, PAYS-BAS  (1978) (Revue)
Elsevier Science Publishers, Amsterdam, PAYS-BAS  (1998) (Monographie)

Mots-clés anglais / English Keywords

United States

;

Air pollution

;

Air quality

;

Pollutant emission

;

Photochemical oxidants

;

Smog

;

Atmospheric chemistry

;

Pollutant creation

;

Pollution prevention

;

Motor vehicle

;

Catalytic converter

;

Modeling

;

Legislation

;

Ozone

;

Case history

;

North America

;

America

;

Mots-clés français / French Keywords

Etats Unis

;

Pollution air

;

Qualité air

;

Emission polluant

;

Oxydant photochimique

;

Smog

;

Chimie atmosphérique

;

Formation polluant

;

Prévention pollution

;

Véhicule à moteur

;

Convertisseur catalytique

;

Modélisation

;

Législation

;

Ozone

;

Historique

;

Amérique du Nord

;

Amérique

;

Mots-clés espagnols / Spanish Keywords

Estados Unidos

;

Contaminación aire

;

Calidad aire

;

Emisión contaminante

;

Smog

;

Formación contaminante

;

Prevención polución

;

Vehículo de motor

;

Convertidor catalítico

;

Modelización

;

Legislación

;

Ozono

;

Histórica

;

America del norte

;

America

;

Localisation / Location

INIST-CNRS, Cote INIST : 19645, 35400007459168.0230

Nº notice refdoc (ud4) : 1820599



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