EPA AirNow reported moderate PM2.5 concentrations over several regions, most of them where fires and smoke are present. The Northeast, Mid-Atlantic, Central States and Pacific Northwest regions reached moderate levels throughout the day (top left). Unhealthy levels were read in some stations in California, Washington and Idaho. Fires story continue over several states as discussed in the previous weeks. According to HMS, the large number of wildfires in the western US continue to generate a large quantity of smoke that is spreading across the northern tier of states across the country and into the Atlantic with an area also peeling off to the south through the Plains into northern Mexico. The smoke mainly extends from the fires in Idaho, western Montana and northwest
Wyoming eastward across the Dakotas, the northern Mississippi Valley, the Great Lakes States, New England and the northern mid Atlantic, southeast Ontario and southern Quebec and finally exiting off the coast of New England and New Jersey (top left).
In addition to the smoke in the US, two separate areas of light smoke are located in Canada. The first is over Hudson Bay and moving east and the second extends from southern Nunavut into northern Manitoba and Saskatchewan. The origin of these two plumes is also likely to be from the wildfires in the northwestern US. Aerosol Optical Depth (AOD) retrievals by MODIS instrument on AQUA satellite shows high AOD levels over the above mentioned areas cover by smoke (bottom).
SPECIAL FEATURE: Flying through Formaldehyde
In the past few years, NASA scientist Tom Hanisco has been hunting for formaldehyde, a carcinogenic air pollutant common in smoke. A byproduct of combustion, formaldehyde affects human health and also has significant--but little understood--effects on Earth's atmosphere. For instance, chemical reactions that break down formaldehyde in the lower atmosphere can produce small airborne particles that have an outsized influence on Earth's climate. Other reactions involving formaldehyde affect the production of ozone.
Hanisco's tool for tracking the short-lived and elusive pollutant is a lightweight aircraft sensor he developed at NASA's Goddard Space Flight Center. Called the In-Situ Airborne Formaldehyde (ISAF), the sensor uses lasers to measure the abundance of formaldehyde in the atmosphere.
ISAF is one of 28 sensors mounted on NASA's DC-8, a research airplane used in the NASA-led SEAC4RS field campaign, which stands for Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys. The campaign began in August and will continue through the end of September. The broad goal is to investigate how the combination of summer storms and pollution from wildfires, cities, and other sources affect air quality and the workings of Earth's climate. (Full article: Earth Observatory)