Camphor, known for its distinct, pungent aroma, is a chemical compound that occurs naturally in the wood of the camphor laurel tree, Cinnamomum camphora. Today, camphor is also commonly produced synthetically from turpentine oil, creating a product with the same chemical structure and properties.
The long history of using camphor as a repellent against various pests, including moths and mosquitoes, has led to a widespread belief in its efficacy as a natural solution. This traditional use, however, requires scientific examination to determine its protective capabilities against disease-carrying mosquitoes.
Scientific Findings on Mosquito Repellency
Scientific study offers moderate support for camphor’s use as a mosquito repellent, particularly in confined spaces. Camphor deters insects from an area or a host, rather than acting as a quick-acting insecticide that kills them. The strong, volatile odor is attributed to its active component, borneol, which is released as the solid sublimates or is heated.
The mechanism involves confusing the mosquito’s olfactory system, which mosquitoes use to locate humans. Mosquitoes primarily track their targets by sensing carbon dioxide and other volatile compounds in human sweat. The intense aroma of borneol acts as a sensory irritant and masking agent, disrupting the mosquito’s ability to follow these chemical trails. Laboratory and field studies have demonstrated that camphor oil can be effective, with one study showing it provided nearly 98% protection against the Anopheles culicifacies mosquito, which transmits malaria. However, camphor’s duration of effect is shorter than that of synthetic repellents, and its efficacy can vary depending on the specific mosquito species and concentration used.
Traditional Methods for Using Camphor
Traditional application methods focus on maximizing the release of camphor’s vapor into the surrounding air. One common technique involves placing solid camphor tablets or balls in strategic locations, such as near windows, entry points, or inside closets, allowing them to slowly evaporate at room temperature. The strong scent is continuously released as the solid substance transitions directly into a gas.
A more intense method involves heating or burning the camphor to rapidly diffuse the fumes into a room. People often light a piece of camphor in a metal container and close off the room for a short period to allow the concentrated smoke to permeate the area. Another method is to use an electric vaporizer, where a tablet is placed on a heating element to ensure a steady release of the vapor over several hours. Some traditional remedies also call for dissolving camphor in a carrier oil or water to create a localized solution, although this method carries greater safety concerns regarding skin exposure.
Important Safety Considerations
Despite its natural origins, camphor is a flammable substance and carries toxicity risks that must be carefully managed. Camphor is readily absorbed through the skin, and applying concentrated camphor oil directly to the skin can lead to irritation, redness, and systemic toxicity. The risk is particularly high if the skin is broken or damaged, as absorption increases.
The greatest danger is from accidental ingestion, especially in children, where even small amounts can be life-threatening. Ingesting camphor can rapidly cause central nervous system stimulation, leading to symptoms like nausea, vomiting, mental confusion, and severe seizures. Doses exceeding 30 milligrams per kilogram of body weight are considered toxic and require immediate medical attention. When using camphor for fumigation, burning it should only be done with caution and proper ventilation to prevent fire hazards and avoid inhaling high concentrations of the fumes, which can cause respiratory irritation and dizziness.