He investigates ambient particulate matter and climate change.

Brett Toubman ASU

Brett Toubman, Assistant Professor of Chemistry at Appalachian State University, is an environmental scientist who is measuring aerosols that are being pumped into the atmosphere.

Most people think of spray cans when they hear the word “aerosols”. When atmospheric scientists use the term, however, they are referring to particles suspended in the atmosphere. Particles can be naturally occurring, such as dust or sea salt particles, or man-made, such as soot emitted from diesel engines..

Aerosols have many sources and come in many different forms. They may be emitted directly into the atmosphere as particles (primary particles) or they may form in the atmosphere when gases condense to form particles (secondary particles). There are both natural and man-made sources of aerosols. Natural sources include dust, sea salt, volcanic emissions, and emissions from plants. The first three sources are examples of primary particles, while plant emissions are an example of precursor gases that form particles secondarily in the atmosphere. In fact, the Great Smoky Mountains got their name from the smoke-like haze that hangs over the mountains. But the haze is not from smoke. It is caused by natural emissions from the trees, which then condense into particles that scatter the sunlight creating the hazy conditions. Man-made sources of aerosols include emissions from vehicles, power plants, agriculture, and industry. Forest fires are another large source of atmospheric particles and may be either natural or man-made. With so many sources and pathways to particle formation, it’s no wonder each individual particle is so complex!.