The National Bureau of Economic Research released a report this month investigating the recent increase in air pollution by region in the United States. After a decade of improving air quality with a decrease in the presence of particulate air matter by 25%, the United States has experienced an increase pollution between 2016 and 2018. The largest increases have stemmed out of the Midwest and West. The report speculates that pollution increases are the result of higher economic activity, lower environmental regulatory enforcement, and wildfires. Read More.