The overall air quality impacts of the 710 Gap Closure are extremely beneficial from a regional perspective. Total Organic Gas and Carbon Monoxide are reduced significantly within the region as average freeway speeds increase with the new freeway network link. Although at higher freeway speeds Nitrogen Oxide is emitted at higher rates than at the sluggish speed of vehicles on city streets, the region has met the National Clean Air Act requirement for Nitrogen Oxide. Thus, overall emissions from the 710 Freeway improves the regional air quality, especially with respect to the most critical pollutant – TOG – that is the key element in ozone smog formation.

The 710 Freeway also is projected to reduce the emission of TOG within the 710 corridor itself. Thus, smog producing pollutants will be reduced in the corridor cities next to the freeway. Although there are some increases in other pollutants within the 710 corridor itself, these less important pollutants are already in conformance with the applicable air quality plans of the region.

Recent modeling by the Southern California Association of Governments shows the 710 Freeway will remove about 1.1 tons of air pollutants each day. That equals 803,000 pounds of air pollutants removed from the air every year, according to the Multi-Mode, Low-Build study summarized above. In the Environmental Impact Statement the reduction is even more dramatic. In that study the total emissions are projected to be 8.2 tons less after the freeway is completed. According to this study the reductions are divided as follows: TOG 692kg, CM 8,213kg, Nitrogen Oxide 161kg.

Source: Multi-Mode, Low-Build study