99% of the world's population is exposed PM 2.5 at unhealthy levels according to Lancet Planetary Health's recently released study. The Washington Post author Kasha Patel highlights:

In 2019, they found 0.001 percent of the global population is exposed to levels of PM 2.5 pollution that the World Health Organization deems safe. The agency has said annual concentrations higher than 5 micrograms per cubic meter are hazardous.

Wildfires have devastated large swaths of the western states resulting in a range of catastrophic consequences. The wine grape growers and vintners in Washington, Oregon and California have lost hundreds of millions of dollars due to grapes that become unsuitable for wine due to damage from wildfire smoke.

A recent study by the University of Leeds and the Southern University of Science and Technology in Shenzhen divulged PM2.5 had only a small reduction across China and it was not lowered at all in Northeast China. The PM2.5 reduction of 11% across China was disappointing in comparison to the reduction 27% of NO2 across China.  

Nineteen researchers from the University of California, Davis, have been named in the annual Highly Cited Researchers 2018 list released by Clarivate Analytics. The list identifies exceptional scientists and social scientists who have demonstrated significant influence by publishing multiple papers that rank in the top 1 percent by citations in a particular field and year, over a 10-year period.