See more at the link https://denver.streetsblog.org/2019/...-than-beijing/

Excerpt:

Today from downtown Denver, the peaks of the Rocky Mountain foothills were barely visible through the brown cloud of pollution that covered the region with an unhealthy level of fine particulate matter.

At six p.m., Denver’s air quality index measured 162, an unhealthy level more than three times worse than the moderate rating of 51 now in Beijing. The pollution triggered health warnings across the northern Front Range.

Colorado’s “brown cloud” is an increasingly frequent reminder of the Denver-Boulder metro’s car dependency and the impact of the state’s oil and gas production, which the industry projects will generate $12.5 billion in revenue this year.