By By Karen Graham Jul 8, 2014 in Environment Scientists have been trying to quantify the impact of wildfire soot particles on climate change and human health for years. Every year, wildfires consume millions of acres of land, emitting 34 percent of the total global soot mass into the atmosphere. A team of scientists from the Nevada Desert Research Institute, led by Rajan Chakrabarty, has published a paper in Nature Scientific Reports, describing their findings and observation of The research team first discovered the superaggregate soot particles in smoke plumes from the 2012 Nagarhole National Forest fire in western India. Unlike the sub-micrometer sized soot particles emitted from vehicles and cook stoves, the newly discovered particles were 10 times longer, with a more compact shape. Typical soot superaggregates seen from sampling of smoke plumes from the Nagarhole forest fire. Rajan K. Chakrabarty The scientists learned these superaggregates had a low effective density, giving them some similar characteristics to "Our observations suggest that we cannot simply assume a universal form of soot to be emitted from all combustion sources. Large-scale combustion sources, such as wildfires, emit a different form of soot than say, a small-scale, controlled combustion source, such as vehicles," said Chakrabarty, who is also on the faculty at Washington University in St. Louis. To verify the presence of superaggregate soot particles in wildfires, the team studied other wildfires around the world. Samples of smoke were collected and analysed from the 2010 Millerton Lake fire in Northern California, and the 2011 Las Conchas fire in New Mexico, as well as wildfires near Mexico City. It was found that large amounts of the superaggregate soot particles were found during the flaming phase of the fires. There is a basic difference between smouldering and flaming combustion. Smouldering is a surface phenomenon with relatively low heat and temperature, compared to flaming combustion. The Next, the scientists assessed the possible impact superaggregates might have on global climate, assessing the radiating properties of the soot aggregates using a numerically-exact "We found that superaggregates contribute up to 90-percent more warming than spherical sub-micrometer soot particles, which current climate models use," said Chakrabarty. "These preliminary findings warrant further research to quantify the significant impact these particles may have on climate, human health, and air pollution around the world." With the unpredictability of wildfire occurrences and the difficulty in sampling smoke plumes while they are occurring, accurate optical and physical knowledge of soot particles emitted from wildfires has eluded scientists.A team of scientists from the Nevada Desert Research Institute, led by Rajan Chakrabarty, has published a paper in Nature Scientific Reports, describing their findings and observation of previously unknown soot particles . The authors have identified them as "superaggregates" from wildfire emissions.The research team first discovered the superaggregate soot particles in smoke plumes from the 2012 Nagarhole National Forest fire in western India. Unlike the sub-micrometer sized soot particles emitted from vehicles and cook stoves, the newly discovered particles were 10 times longer, with a more compact shape.The scientists learned these superaggregates had a low effective density, giving them some similar characteristics to conventional soot particles when it came to long-range distribution in the atmosphere and the deposition of the particles in human lungs. These findings have led the team to the conclusion that the soot formation mechanism of particles in wildfires needs to be re-investigated."Our observations suggest that we cannot simply assume a universal form of soot to be emitted from all combustion sources. Large-scale combustion sources, such as wildfires, emit a different form of soot than say, a small-scale, controlled combustion source, such as vehicles," said Chakrabarty, who is also on the faculty at Washington University in St. Louis.To verify the presence of superaggregate soot particles in wildfires, the team studied other wildfires around the world. Samples of smoke were collected and analysed from the 2010 Millerton Lake fire in Northern California, and the 2011 Las Conchas fire in New Mexico, as well as wildfires near Mexico City.It was found that large amounts of the superaggregate soot particles were found during the flaming phase of the fires. There is a basic difference between smouldering and flaming combustion. Smouldering is a surface phenomenon with relatively low heat and temperature, compared to flaming combustion. The flaming phase has a rapid high temperature conversion of fuel to thermal energy, often leaving unburned fuel behind.Next, the scientists assessed the possible impact superaggregates might have on global climate, assessing the radiating properties of the soot aggregates using a 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," said Chakrabarty. "These preliminary findings warrant further research to quantify the significant impact these particles may have on climate, human health, and air pollution around the world." More about Wildfires, superaggregates, soot particles, desert research institute, Climate warming More news from Wildfires superaggregates soot particles desert research inst... Climate warming Human health