"I can't speak for other MPs, but I've had many, many calls over the past eight years about chemtrails. And these questions are not so easy to answer," Jan Lindholm, Green Party MP, told The Local.
The queries came from Swedes who were "worried and afraid" about the white trails behind aeroplanes. Many callers were concerned, he said, that the planes were leaving poisonous gases.
Conspiracy theorists suggest that governments are behind the trails, which they claim are a deadly concoction of heavy metals.
"It's an attempt to geo-engineer the planet. We're talking weather control here," one chemtrail enthusiast told The Local on condition of anonymity.
Lindholm, tired of getting the same questions and not knowing how to answer them, took matters into his own hands.
He contacted Sweden's weather agency SMHI, the Swedish Civil Aviation Administration (Luftfartsverket) and the air force. Unsatisfied with their responses, he requested an official probe from Sweden's Parliamentary Investigative Service (Riksdagens Utredningstjänst, RUT).
"They studied it, perhaps for a few hours, I don't know, and they managed to give me a clear answer. Now, if someone asks me, I can answer," he explained.
"I tell them that as far as I know - and I have seen the work done by serious scientists - chemtrails probably don't exist, and probably can't exist."
While the investigation was completed in late 2012, it was only made public this week, reported Nyheter24 news site.
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Lindholm, who described himself as "an old man with an active curiosity", dismissed further claims that the study was a waste of time.
"As an elected person, it is my responsibility to listen. I can't ignore people, I have to try and give them answers," he told The Local.