If you've been following air pollution studies, you must be aware of PM2.5, fine particulate matter, which has been thought responsible for millions of premature deaths worldwide every year. But now, people start to realize that PM2.5 may not be the primary one to blame. Instead, ultra fine particles (PM1) may be responsible, because it can travel even deeper into the lungs and may have more serious health implications than PM2.5.
With more and more attentions on PM1, a recent study (link) by Jing Wei and Zhanqing Li from the University of Maryland presents the first high resolution (1 km) long-term (2014-2018) satellite-derived PM1 estimates over China. Their estimates are based on satellite observations of aerosol optical depth (AOD), ground-based observations of PM1, and a statistical model (space-time extremely randomized trees). Similar method may have been used to investigate PM2.5, but with the first precious long-term PM1 measurements across China, Wei and Li are able to adopt the method to their new PM1 measurements. That is the creativity of this study. Creativity is hardly a creation out of nothing. Rather, it is often a new combination of old materials. If you are interested in this study, please check out:
J. Wei et al:Satellite-Derived 1-km-Resolution PM1 Concentrations from 2014 to 2018 across China, Environ. Sci. Technol. 2019. [Link]