The world's leading atmospheric scientists overwhelmingly deny the existence of a secret, elite-driven plot to release harmful chemicals into the air from high-flying aircraft, according to the first peer-reviewed journal paper to address the "chemtrails" conspiracy theory.

Researchers from the University of California, Irvine, the Carnegie Institution for Science and the nonprofit Near Zero organization asked 77 atmospheric chemists and geochemists if they had come across evidence of such a large-scale spraying program, and 76 responded that they had not. The survey results were published Wednesday in Environmental Research Letters.

Heat from aircraft engines produces condensation trails that can be clearly seen from the ground. A small but vocal segment of the population firmly believes that these are composed not merely of condensed water vapor but of chemicals and elements such as strontium, barium and aluminum that powerful, high-level entities have been intentionally and covertly releasing into the atmosphere for decades.

They find the increased number and lingering presence of these aerial streaks suspicious and claim to have identified toxic substances in soil and water samples.

"The chemtrails conspiracy theory maps pretty closely to the origin and growth of the internet, where you can still find a number of websites that promote this particular brand of pseudoscience," said study co-author Steven Davis, UCI associate professor of Earth system science.

"Our survey found little agreement in the scientific community with claims that the government, the military, airlines and others are colluding in a widespread, nefarious program to poison the planet from the skies."

The belief in chemtrails parallels increasing public distrust of elites and social institutions, according to earlier social science research. To those convinced, the chemicals are sprayed to regulate the food supply, control human population and/or manipulate weather patterns. In recent years, the theory has expanded to include government-sponsored geoengineering to mitigate climate change.

Some of the surveyed specialists suggested that global warming may in itself be a cause of longer-lasting condensation trails from aircraft engines. Another contributor, outlined in the study, is the steady growth of air travel in recent decades, which leads airplanes to fly higher, where contrails are more likely to form and remain in the sky.

"Despite the persistence of erroneous theories about atmospheric chemical spraying programs, until now there were no peer-reviewed academic studies showing that what some people think are chemtrails are just ordinary contrails," said Carnegie investigator and co-author Ken Caldeira.

"Contrails are becoming more abundant as air travel expands. Also, it is possible that climate change is causing contrails to persist for longer than they used to."

The survey's respondents - many of them currently active in research on atmospheric dust and pollution - stressed that methods of collecting samples of water, snow and soil recommended by chemtrails-focused groups may be to blame for faulty results. Obtaining and transporting samples via Mason jars with metal lids, for example, was cited as a poor practice that could lead to erroneous outcomes.

One of the experts questioned wrote: "The jar will contaminate the sample, as will the metal lid, particularly if you shake it. I cannot imagine a worse protocol for collecting a sample; the data would be totally worthless." Another said, "To analyze metals in environmental samples, glass needs to go through an acid wash to remove any residual metals. Otherwise, plastic should be used."

UCI's Davis said: "We don't imagine that we're going to sway the beliefs of hardcore adherents to the chemtrails conspiracy theory with this study. But we thought it was important to go on the record with fundamental scientific facts to refute claims that the government is deliberately spreading harmful chemicals from aircraft."