Smog knows no jurisdictional bounds, and there are few better examples of this than in the Inland Empire of Southern California. The brown haze that forms over the area in the summer time has given San Bernardino and Riverside counties names such as the "SMOG Belt," and although it has improved in recent years, air pollution in the region is still at an unhealthy level according to the American Lung Association's report "State of the Air 2014."

Simply put, smog forms when Nitrous Oxide (NOx), a by-product of combustion, reacts with chemicals in the air and sunlight to produce ozone. The Inland Empire has no shortage of sunlight and cars, as well as a growing warehousing and trucking industry. Furthermore, NOx can easily cross regional boundaries before it reacts with other chemicals.  Southern California geography allows air currents to flow through mountain passes, carrying pollutants into the Inland Empire from the Los Angeles basin. The sources of these pollutants are many, ranging from automobile traffic to economic activity.

The ports of Los Angeles and Long Beach, together, rank as the number one busiest port complex in the nation, experiencing a combined container volume of 14.6 million containers in 2013. Activity from ships traveling in and out of the ports, as well as the unloading, drayage, and trucking activities, produces a significant amount of emissions, though the ports have been successful at reducing their emissions – the Port of LA seeing a NOx emission reduction of 57% as of 2013.

Factors other than emissions can contribute to poor air quality, including pesticides and particulate matter from dust particles scattered by the wind. Since smog forms more easily in hot, dry weather, changing climate conditions, such as an increase in the frequency and severity of warmer weather and drought, have the potential to speed up smog formation.

It is important to think of smog as a regional issue. Agencies such as the South Coast Air Quality Management District are working to reduces emissions, and are seeing air quality improvements, but the fact remains that Riverside County and the Inland Empire still receive failing air quality grades.

What can regions, or even individual jurisdictions do to reduce smog in the air, especially if many of the pollutants come from elsewhere? Is smog a concern in your community? 

Credits: Images by Taylor York. Data linked to sources.