Located 60 miles east downtown LA in the sprawling Southern California megalopolis, the city of Riverside is known as the birthplace of the California citrus industry: Its hot, sunny Mediterranean climate was the perfect place to begin planting orange trees way back in the 1870s. These days, unfortunately, Riverside is also known for its smog.
Riverside sits in what’s known as a “smog belt.” The Riverside-San Bernardino-Ontario area was found to be one of the most polluted regions based on year-round particle measurements when compared to other U.S. cities. Most of Riverside’s smog problems are the result of the prevailing westerlies that blow the smog from L.A. and particulates generated by Southern California’s huge number of vehicles, into the area, where they’re trapped by the San Bernardino Mountains to the east.
Despite smog problems, the city has made efforts to reduce pollution by incorporating additional means of mass transit and equipping its entire fleet of buses with natural gas. Smog has decreased considerably over the past years as local municipalities and counties work with the South Coast Air Quality Management District to implement measures to improve regional air quality.