The acidic rain and fog that have been damaging trees and crops are now slowly eating away homes, buildings and freeways, say scientists who have found that even galvanized steel cannot escape destruction.
Scientists at USC are embarking on a two-year study that will assess the damage of materials susceptible to acid at sites throughout Southern and Northern California to determine the overall economic impact of acidic precipitation.
"Society needs to know how much acid rain and fog are costing us so it can be decided how much expense we can justify in its control," said Florian Mansfeld, a materials science expert at USC.
He said many of the major building materials of Western civilization--aluminum, cement, galvanized steel and paint--are as susceptible as plant life to corrosive destruction brought on by acid rain and fog.
Worse Than Lemon Juice
Chemical analyses of Southern California precipitation at the University of California, Riverside, where scientists are assessing damage to vegetables, show that rain can be as acidic as vinegar and fog more acidic than lemon juice.
State lawmakers, mindful of the problem, enacted the Kapiloff Acid Deposition Act four years ago to study the adverse effects of air pollution and to develop plans to ward off destruction to homes, factories, bridges and freeways.
Government investigations have revealed that damage to such structures most often manifests itself in the form of corrosiveness--small holes, peeling paint or varnish and rust.
Mansfeld noted that state costs for maintenance and replacement of structures has risen dramatically over the last 20 years, reflecting increased destruction caused by acidic pollution.
"In accordance with the Kapiloff Act, the California Air Resources Board has been funding research programs, such as ours, to obtain an inventory of materials to determine the relationship between materials damage and atmospheric deposition," Mansfeld said.
The inventory of damage to such materials as wood, steel, cement and aluminum will be taken at sites in Long Beach, Burbank, Upland and Salinas during the two-year study period, Mansfeld said.
Along with the inventory, scientists also plan to construct two special test chambers, one to produce acid rain and another that will simulate the conditions of acid fog.
"We will conduct 28-day tests of the reactions of specific materials with specific components of acid rain and acid fog," the scientist said.
4 Chemical Culprits
Mansfeld defined the chemical culprits in acidic precipitation as ozone, sulfur dioxide, oxides of nitrogen and chlorides.
Automobile and factory emissions, particularly petroleum refining and chemical manufacturing in Southern California, are responsible for the tons of pollutants that drift into the atmosphere directly over the region, USC scientists say.
But Mansfeld and his team note that the release of sulfur and nitrogen oxides into the air are only the first act in an atmospheric drama that results in acid fog and rain.
The sulfur and nitrogen undergo complex chemical changes while in the air, combining with water vapor miles above the Earth's surface and collecting in clouds that return the acids to the surface as precipitation.
Southern Crops Damaged
UC Riverside scientists studying the effects of acid fog on agriculture say the ozone concentration in acid fog is particularly damaging to Southern California crops.
"We still consider ozone to be the No. 1 air pollution problem because typical levels cause high yield losses. Beans, spinach and lettuce are no longer grown in urban areas of Southern California because the ozone damage makes it uneconomical," said UC Riverside plant physiologist Robert Musselman.
Musselman and UC Riverside researchers began studying the effects of acid fog three years ago after studies that showed fog in Southern and Central California more acidic than acid rain.
"Typical acid fogs have measured as acidic as lemon juice, about 100 to 1,000 times more acidic than unpolluted clean rainfall and about 10 times more acidic than acid rain," Musselman said.
Human Health Studies
USC's research team plans to expand its studies of acid precipitation to include investigations of their effects on human health. Experts in the university's environmental and health sciences departments will join later portions of the study, Mansfeld said.
The U.S. Department of Agriculture also is conducting acid rain and fog studies mandated by Congress in 1980.
"We need more information about plant responses to gaseous precipitation like acid fog," said USDA plant physiologist Jack Barnes.
"The results of these studies, along with others, could provide a basis for policy makers to make regulatory decisions," he said.
'Typical acid fogs have measured as acidic as lemon juice, about 100 to 1,000 times more acidic than unpolluted clean rainfall and about 10 times more acidic than acid rain.'
UC Riverside plant physiologist