New soot particle from wildfire emissions discovered

A study led by Indian-origin researcher Rajan Chakrabarty has found a previously unrecognised form of soot particle, identified by the authors as "superaggregates", from wildfire emissions, offering new insights into global climate study.

These newly identified particles were detected in smoke plumes from wildfires in the US, Mexico and India.

"Our observations suggest that we cannot simply assume a universal form of soot to be emitted from all combustion sources," said Chakrabarty from Desert Research Institute in the US.

"Large-scale combustion sources, such as wildfires, emit a different form of soot than say, a small-scale, controlled combustion source, such as vehicles," Chakrabarty, who also holds a faculty appointment at Washington University in St. Louis, added.

Unlike conventional sub-micrometre size soot particles emitted from vehicles and cook stoves, superaggregates are on average ten times longer and have a more compact shape.

To assess the potential impact of superaggregates on global climate, scientists also calculated the radiative properties of soot superaggregates using numerically-exact electromagnetic theory.

"We found that superaggregates contribute up to 90-percent more warming than spherical sub-micrometer soot particles, which current climate models use," Chakrabarty noted.

The findings appeared in the journal Nature Scientific Reports.