Using infrared geostationary remote sensing to determine particulate matter ground-level composition and concentration

• Published in: Air quality, atmosphere and health Vol. 17; no. 6; pp. 1183 - 1192
• Main Authors: Sowden, M., Blake, D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2024; Springer Nature B.V
• Subjects: Aerosol composition; Aerosol concentrations; Aerosols; Air pollution; Air quality; Air sampling; Air temperature; Airborne particulates; Atmospheric models; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric stability; Brightness; Brightness temperature; Dust; Dust filters; Dust storms; Earth and Environmental Science; Emissions; Environment; Environmental Health; Forest & brush fires; Geostationary satellites; Health Promotion and Disease Prevention; High pass filters; Indoor air quality; Infrared radiation; Outdoor air quality; Ozone; Particle size; Particulate emissions; Particulate matter; Remote monitoring; Remote sensing; Satellites; Smog; Spatial analysis; Spatial discrimination; Spatial resolution; Spectral sensitivity; Storms; Synchronous satellites; Temperature gradients; Temporal resolution; Wildfires; Australia; Ground-level concentrations; Himawari-8; Aerosol; Remote sensing
• ISSN: 1873-9318; 1873-9326
• DOI: 10.1007/s11869-021-01061-3

Speciated ground-level aerosol concentrations are required to understand and mitigate health impacts from dust storms, wildfires, and other aerosol emissions. Globally, surface monitoring is limited due to cost and infrastructure demands. While remote sensing can help estimate respirable (i.e. ground level) concentrations, current observations are restricted by inadequate spatiotemporal resolution, uncertainty in aerosol type, particle size, and vertical profile. One key issue with current remote sensing datasets is that they are derived from reflectances observed by polar-orbiting imagers, which means that aerosol is only derived during the daytime and only once or twice per day. Newer quantification methods using geostationary infrared (IR) data have focussed on detecting the presence, or absence, of an event. The determination of aerosol composition or particle size using IR exclusively has received little attention. This manuscript summarizes four scientific papers, published as part of a larger study, and identifies requirements for (a) using infrared radiance observations to obtain continual (i.e. day and night) concentration estimates; (b) increasing temporal resolution by using geostationary satellites; (c) utilizing all infrared channels to maximize spectral differences due to compositional changes; and (d) applying a high-pass filter (brightness temperature differences) to identify compositional variability. Additionally, (e) a preliminary calibration methodology was tested against three severe air quality case study incidents, namely, a dust storm, smoke from prescribed burns, and an ozone smog incident, near Sydney in eastern Australia which highlighted the ability of the method to determine atmospheric stability, clouds, and particle size. Geostationary remote sensing provides near-continuous data at a temporal resolution comparable to monitoring equipment. The spatial resolution (~ 4 km
2
at NADIR) is adequate for large sources but coarse for localized sources. The spectral sensitivity of aerosol is limited and appears to be dominated by humidity changes rather than concentration or compositional changes. Geostationary remote sensing can be used to determine the timing, duration, and spatial extent of an air quality event. Brightness temperature differences can assist in qualifying composition with an order of magnitude estimate of concentration.