FOTOS: Los Ángeles encubierto | Smog a través de los años

Buildings in Los Angeles Civic Center are barely visible in picture looking east at 1st and Olive Streets when smog was at its peak.   (John Malmin / Los Angeles Times)

Downtown Los Angeles shrouded in smog as seen from the top of the Angels Flight funicular on December 19, 1958.

There is limited visibility in this 1959 image of a smog attack in downtown Los Angeles looking south on Broadway from 1st Street.

The tall buildings in downtown Los Angeles rise above a blanket of smog in October 1973.

Smoggy view of the civic center area of downtown Los Angeles in March 1974 from the roof of the Dept. of Water and Power building.

View of downtown Los Angeles civic area from the roof of the Arco tower in July 1978.

Aerial view of downtown Los Angeles with the junction of the Harbor and Santa Monica Freeways in the foreground in July 1982.

April 1988 view of Torrance beach looking north from Palos Verde Estates.

The Los Angeles skyline shrouded in smog as seen from the 1st street bridge in July 1993.

The downtown Los Angeles skyline peaks out above a layer of smog as seen from Griffith Park.

The state and regional air quality officials warn that dispite years of efforts and billions of dollars in programs, Southern californiaand the San Joaquin Valley won’t meet federal smog targets.

A view of downtown Los Angeles from Hilltop Park in Signal Hill. A high pressure system along the West Coast that has been warding off rain for months has also worsened air pollution across California and the Southwest, leaving a brown haze hanging in the air many days.

Downtown skyscrapers reflect the light from the setting sun as seen from more than 20 miles away on the Palos Verdes Peninsula.

Southern California is experiencing its worst smog in years this summer as heat and stagnant weather increase the number of bad air days and drive up ozone pollution to levels not seen since 2009.