A Hampshire Fire and Rescue Service spokesman said it had received more than 20 calls about the smell, mostly in the Portsmouth area, with reports that it had been noticed as far north as Basingstoke and Andover and as far west as Ringwood.
Group manager Tony Deacon said:
Our control room has dealt with a number of calls reporting the unpleasant gas smell.
We want to reassure the public that the gas presents no threat to health and is completely harmless.
We would also like to remind the public that if they suspect they are dealing with a genuine gas emergency in their home or building, they should call the National Gas Emergency Number on 0800 111999.
More top news
Satoshi Uematsu, 26, was sent to the Yokohama District Public Prosecutors Office in Kanagawa prefecture.
West Yorkshire Police confirmed a 32-year-old woman was taken into custody in connection with the alleged threats.
Five women shared their views about whether Hillary Clinton's Democratic presidential nomination is a defining moment in US history.