Acid rain and automotive paint finishes

Acid Rain Facts & Fiction:  

You may have read or  heard horror stories about acid rain. Unfortunately most information regarding acid rain and automotive paint finishes is at least slightly incorrect or, in some cases, totally wrong. Let' s set the record straight and clear away all the old wives' tales about acid rain. With that accomplished, you should be able to explain to your our customer’s at 6th Avenue Car Wash what it' s all about.


Manufacturing plants, power-generating plants, internal combustion engines, jet engines, etc. all produce sulfuric dioxides, which are released in their exhaust fumes. Smog, well known in major cities, contains these chemicals. When smog settles on a surface such as an automobile fender it is known as industrial fallout, or IFO. When ozone, water and heat are applied to IFO it becomes acid rain, right on the paint' s surface.

You may ask, "Don' t catalytic converters on our cars get rid of sulfuric emissions?" Only partially . Whatever changes the converter accomplishes in the sulfuric compounds are reversed by the effect of ozone and water.

Nitric oxides are additional acid rain components. The nitrics were originally thought to be a large part of the problem. However, recent data have shown they are not a real contributor to acid rain problems on vehicle paint finishes . there are, of course, exceptions.

While all manufacturing plants contribute to the nationwide pollution problem, one type stands out as an example of a sever localized producer of acidic contaminates . paper or pulp mills. These mills use an acidic process to break down wood fiber. A major portion of the acid compounds utilized is nitric acid. The nitric acids combine with other acids emanating from the process to create a mini acid-rain belt in the area around the facility.

When the emitted acids combine with particulate matter and then settle on an automobile finish, severe acid etching may take place in a very short period of time.

As a result of this localized pollution problem, many paper mills have a car wash on site so employees can remove the acid compounds from their vehicles at the end of their work shift. Others contract with a quality local car wash to clean their employees' vehicles.

A far worse emission is hydrazine. This extremely active acid is a component of jet fuel. So a vehicle parked regularly around a major airport or in high-usage flight paths will be subjected to hydrazine acids on its painted surfaces. Hydrazine is extremely reactive to oxidizers such as ozone.

An oxidizer is any compound that spontaneously emits oxygen either at room temperature or under slight heating. Many chemical compounds react vigorously at ambient temperatures as the oxidizing process takes place. Hydrazine, due to its molecular chain of hydrogen and nitrogen atoms, reacts violently, eating at any surface where it is concentrated. Any of us who took basic chemistry in high school or college remembers our instructor' s caution: "Always add the acid to the water . never, never add the water to the acid!"