Emission Trends
Emissions of precursors for both ozone and particulate matter have decreased steadily in the Sacramento region due to implementation of local, state, and federal emission control programs.
Ozone precursors
The precursors associated with ozone are volatile organic compounds (VOC) and oxides of nitrogen (NOx). The emissions inventory graphs show the VOC and NOX trends during the summer months (May through October). Summer is typically when ozone concentrations are the highest. The emission trends show significant declines in emissions, despite increasing population, vehicle activity, and economic development.
The largest reduction in emissions was from on-road motor vehicles, where there was a 66% reduction for VOCs and 62% for NOx from 2000 to 2015. The drop in NOx and VOC emissions corresponds to attainment of the 1979 1-Hour Standard in 2009 (attainment was based on data from 2007 – 2009).
Data source: CEPAM: 2016 SIP Baseline Emission Projections, Section a1 – Emission Projections With External Adjustments, Sacramento NAA 2016 Ozone SIP Version 1.04.
Data source: CEPAM: 2016 SIP Baseline Emission Projections, Section a1 – Emission Projections With External Adjustments, Sacramento NAA 2016 Ozone SIP Version 1.04.
Fine Particulate Matter and Precursors
Fine particular matter can be emitted directly or formed by chemical reactions of precursors - nitrogen oxide (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), and ammonia (NH3). This figure shows how much precursor emissions have decreased since 2005, and are expected to continue to decrease in the future despite an increase in population and economic growth.
Data Source: CEPAM: NORCAL 2012 PM2.5 SIP Baseline Emission
Projections, Section a1 – Emission Projections With External Adjustments,
Sacramento Nonattainment Area 2012 PM2.5 SIP Version 1.01.