History of Air Pollution Control in Southern California

Note from the Web Editor: The following pages are not maintained. The information is included for historical interest only, and should not be relied upon for accuracy for current air quality control procedures or standards. 

  • The Southland's War on Smog: Fifty Years of Progress Toward Clean Air  (online version of 32-page brochure), May 1997

  • Anecdotes Illustrate 50-Year History of War on Smog, June 1997

  • Downtown LA Smog Monitoring Station Has Seen Many Changes, May 1997

  • UC Riverside Ran Early Studies on Effects of Smog on Plants, May 1997

  • Upland, Calif., had Last Stage III Episode in U.S., May 1997

  • Orchard Smudge Pots Cooked Up Pall of Smoke, May 1997

  • From Tunnels to Turbines: Old Ideas for Ridding Area of Smog, May 1997

     Anecdotes Illustrate 50-Year History of War on Smog

    Southern California residents take it for granted that air pollution control is a highly sophisticated science backed up by a world-class air quality monitoring network. It wasn't always so.

    • One of the first indications of the ill effects of smog was its damage to plants. Read about early research into plant damage at the University of California, Riverside.

    • The first smog monitoring network wasn't established until the 1950s. One of the first stations still monitors pollutants in downtown Los Angeles.

    • Southland residents endured extremely hazardous ozone levels until 1974, when the last Stage III episode was recorded in Upland.

    • Early air pollution officials had to contend with some serious pollution problems that no longer exist, such as orchard .

    • In their quest for clean air, Southland residents and engineers thought of just about everything to sweep away smog, including the installation of giant fans.

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    Downtown L.A. Smog Monitoring Station Has Seen Many Changes

    As the region's oldest air quality monitoring station, the South Coast Air Quality Management District's downtown Los Angeles station has been home to the gamut of technologies used through the years to measure air pollution.

    The station was first operated by the old Los Angeles County Air Pollution Control District at 5201 Santa Fe St. before being relocated to the agency's headquarters at 434 South San Pedro in 1955. In 1979 it was moved to its present location at the Los Angeles Department of Water and Power facility at 1630 N. Main St.

    The highest ozone level the station ever recorded was .68 parts per million in 1955 and the lowest was .14 ppm in 1996. Ozone is a chief component of smog.

    During the station's early years, everything was done by hand. Air pollution researchers set jars outside for up to 36 hours to collect fallout air samples. Then using qualitative and quantitative laboratory methods they determined air quality levels.

    "As far as automated sampling went, we passed air samples through a liquid agent that changed colors based on the properties of the contaminant in the sample," said William Bope, who then worked for the Orange County Air Pollution Control District and is now manager of AQMD's Atmospheric Measurements Division.

    The monitoring equipment was large, cumbersome and would be subject to interference from time to time, Bope said.

    In addition to equipment, the laboratory was home to a variety of small animals used to test the health effects of air pollution. Rats, mice and guinea pigs were exposed to rooms filled with clean and ambient air concentrations. After the animals died, the scientists examined their lung tissue and respiratory systems. This information was used to help establish smog alert levels.

    "The electronic age, beginning in the 1970s, helped to greatly reduce the size of our equipment," said Bope. "It also enabled us to gather information more quickly and produce more reliable data."

    Today, modern technology instantaneously measures air quality. The public can obtain current air quality reports from AQMD at 1-800-CUT-SMOG and through AQMD's Internet site.

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    UC Riverside Ran Early Studies on Effects of Smog on Plants

    May 1997
    In the early 1940s, Southern California farmers and Cooperative Extension personnel recognized an unusual type of damage to the leaves of plants. They called upon plant pathologists at what is now the University of California at Riverside to help identify the cause.

    Farmers observed that sugar beets and many other leafy vegetables were shriveled and discolored with mottled silver or bronze-colored lower leaves that made them unappetizing and unattractive.

    Growers immediately pointed to industry as the culprit for releasing toxic chemicals into the atmosphere, poisoning their crops below. Gardena truck farmers were increasingly alarmed at their shrinking sugar beet harvests. Then in July 1950, Dominiguez growers brought a suit against one local chemical manufacturer, citing it as a source of industrial air pollution.

    Riverside scientists were the first to determine that this sick plant syndrome was not caused by known industrial pollutants, but by "secondary" air pollutants, namely ozone and other photochemical oxidants.

    Setting up plastic tent-like enclosures in an Upland, Calif. lemon orchard, Clifton Taylor, Ph.D., and Ray Thompson, Ph.D., conducted the first scientific attempt to measure the effects of smog on commercial citrus in 1950. They used elaborate equipment for comparing the effects of "natural" and synthetic air pollutants on 24 trees spread through the orchard. Thompson, then director of the research center, spearheaded the project.

    To unravel the complex problem of photochemical smog, the plant researchers drew on the expertise of atmospheric chemists, beginning a collaboration between these two branches of science that continued for over two decades.

    Today, research into the effects of smog continues at UCR's Statewide Air Pollution Research Center. Sophisticated analytical methods help scientists to identify and measure trace substances in the air.

    Plant science studies benefited researchers tremendously by allowing the development of improved ozone monitors, exposure chambers and portable instruments. These modern-day tools have enhanced the study of plants response to polluted air.


    Statewide Air Pollution Research Center
    211 Fawcett Laboratory
    University of California at Riverside

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    Upland, Calif., Had Last Stage III Smog Alert in U.S.

    - May 1997

    Thursday, June 27, 1974, was the beginning of a smog siege in Southern California's Inland Empire.

    Temperatures topped 100 degrees and stagnant air caused ozone levels in the city of Upland to become literally hazardous at .51 parts per million. It was the last recorded Stage III smog episode in the nation.

    Media attention turned to the San Bernardino County Air Pollution Control District.

    "We did not yet have a plan to deal with this type of emergency, let alone the media frenzy that came with it," said Mel Zeldin, who was then the meteorologist and unofficial spokesperson for the 26 staff member APCD.

    In April that year the air pollution control agencies in the region devised a three-stage smog warning system that gave each county authority to halt all commercial, industrial and recreational activities (excluding emergency services, like the fire and police departments) during Stage III episodes. A Stage III episode is defined as when the ozone level remains above .50 ppm for one hour or more.

    Unfortunately, no emergency action procedures yet had been developed when the June smog siege hit. For several days news reporters, area residents and local, state, and federal agencies besieged the San Bernardino agency with calls.

    "Everybody wanted to know what to do," said Zeldin, now director of the South Coast Air Quality Management District's Applied Sciences and Technology Division.

    That evening Gov. Ronald Reagan issued a statement urging residents to "limit all but absolutely necessary auto travel" and recommending that those who must drive do so at reduced speeds to lessen vehicle emissions.

    "Carpooling and mass transit should be used whenever possible," he said.

    Without an established plan, some took voluntary steps to reduce pollution. On Friday, June 28, California Portland Cement in Bloomington and Kaiser Steel in Fontana curtailed some operations and Southern Pacific Pipeline delayed truck deliveries of gasoline to local service stations.

    The county garaged its fleet of vehicles; the Parks and Recreation Department closed all municipal swimming pools and moved all scheduled outdoor programs inside; and federal employees with respiratory ailments or breathing problems were told Thursday not to report to work on Friday.

    Lower temperatures and increased winds gradually reduced the smog build-up and the emergency eased over the next several days.

    Editor's Note: Much of the information herein is from The Sun-Telegram newspaper of San Bernardino.

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    Heaters First Regulated in 1950

    Orchard Smudge Pots Cooked Up Pall of Smog

    -  June 1997
    During the winter of 1949-1950, freezing weather gripped the Southland's citrus industry for the third year in a row, prompting growers to fire up millions of smoky orchard heaters that filled the air -- and lungs -- with black smoke.

    "You'd blow your nose, and it would be black," said Edward Camarena, a former chemist with the Orange County Air Pollution Control District, the first air quality agency to regulate orchard heaters, popularly known as smudge pots. Wintertime atmospheric inversions also trapped the thick smoke close to the ground.

    "I can remember getting up and going to work and seeing this ugly black haze where they had smudged most of the night," said Jack Adame, a retired University of California, Riverside employee and now the volunteer master gardener for the University of California Cooperative Extension -Riverside County.

    Following World War II, air pollution captured the public's attention, and orchard heaters, like smoking diesel trucks and open burning at garbage dumps, were a significant and visible source of smog.

    -- From the Pasadena Star-News, Oct. 20, 1947

    In the fall of 1947, Louis C. McCabe, director of the newly formed Los Angeles Air Pollution Control District, appealed to Southland citrus growers to eliminate smoke from more than 4 million orchard heaters.

    "There was a belief that smoke helped hold the heat in, and therefore, smoke was good," Camarena said.

    McCabe and agricultural authorities launched a campaign to educate growers on how to operate heaters so they prevented frost damage to crops, but didn't belch out black clouds.

    In 1950, the Orange County Air Pollution Control District adopted a regulation prohibiting the use of dirty fuels, including old tires and used motor oil, in smudge pots. They also banned the smokiest smudge pots, which included garbage pails.

    Seven other air pollution control districts and the state Air Resources Board subsequently adopted similar rules. Other factors contributed to the demise of the smudge pot.

    1950s brochure advising growers on the use of smudge pots

    During the early 1950s, growers started using wind machines in place of smudge pots. A large propeller mounted on a tower mixed pockets of cool and warm air in orchards, effectively raising temperatures at the ground and preventing frost damage. The wind machines were more expensive to buy, but cost-effective over a period of years because they didn't have to be constantly tended, as smudge pots did, by a small army of laborers.

    Orchard heaters fell out of use completely by the 1970s, Adame said. In addition, almost all commercial citrus growing has moved out of the area to the state's Central Valley, he said.

    Today, residents might still see the rusted hulk of a smudge pot lying in an orange grove, serving as a reminder of a bygone era and a polluting nuisance put in its place by clean technology.

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    From Tunnels to Turbines: Old Ideas for Ridding Area of Smog

    Since smog was first recognized as a serious problem in 1947, inventors and engineers have proposed innovative ideas to get rid of it.

    One was to connect all Los Angeles industries to a massive network of concrete exhaust pipes routed to the mountains where pollution could be released above the inversion layer.

    If it works for sewage, it will work for air pollution, thought the engineering firm that pioneered the "air sanitation system" concept.

    But the system would have required 89 miles of ductwork and the energy to move the large volumes of air would have been several times beyond what Hoover Dam could supply.

    Many other ideas surfaced in the 1950s and 1960s to purify, ventilate or wash the air over Los Angeles.

    One was to cut holes in the mountains and install huge exhaust fans to blow smog out of the basin. However, blowing or washing away smog proved to be impractical since it involved a land mass of 1,600 square miles and over 200 million tons of air. The enormous energy requirements made the idea impossible.

    One scientist suggested blackening whole sections of the eastern mountains so as to store heat and create thermal currents and westerly winds that would blow smog over the ocean.

    Seeding clouds to create rain to "wash the air clean" was one method several experts recommended in the late 1950s. Installing jet engines attached to vertical tubes to propel the smoggy air above the inversion layer also was suggested in 1961.

    In 1967, a respected Penn State chemistry professor thought he had a better idea. Instead of spending money on tailpipe pollution controls, why not simply fumigate the urban air each summer smog season with a chemical called diethylhydroxylamine, or DEHA. The professor said that would interrupt smog formation because DEHA scavenges the short-lived free radicals that fuel the airborne chemistry of smog.

    The only problem was that the chemical posed an even greater health risk than air pollution.

    Although these ideas seem quaint today, they were seriously evaluated at a time when no one knew the cause of air pollution or how to control it.

    Many other ideas eventually proved successful at reducing pollution, such as baghouses to control dust from factories, vapor recovery systems with "booted" nozzles at gas stations, catalytic converters on cars and powerplants and reformulated gasoline.

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