Bolsonaro said he had asked U.S. President Donald Trump for “help” and that Trump had said “he couldn’t make a decision without hearing from Brazil.”

The talks are continuing despite Brazil's initial rejection of international funding to help fight fires in the Amazon, apparently over a personal spat with France's President Emmanuel Macron.

NASA noted that pollutants can travel great distances, and that carbon monoxide in particular can remain in the atmosphere for as long as a month.