print logo
Main Content Anchor

Air Quality Trends

The SacMetro AQMD evaluates trends in air quality concentrations and emission inventories to monitor progress towards meeting federal and state air quality standards.

Concentration Trends

Ozone

The 8-hour ozone (O3) peak design value (an average of the 4th highest ozone concentration over three years) is the highest design value at any site in the Sacramento Federal Nonattainment Area (SFNA) and compared against current and past ozone standards to determine attainment. There is a decreasing trend in ozone concentrations measured at the peak monitoring sites. Meteorology plays an important role in ozone formation and the variability in design value concentrations. Ozone concentrations are usually highest in the summer when it is hot and when there are light winds. 

 

 Data source:  EPA's AQS database downloaded 08/02/2016, https://www.epa.gov/aqs/

 

Particulate Matter

The region has made significant progress in reducing ambient PM2.5 concentrations since 2007, after implementation of wood burning controls.


Data source:  EPA's AQS database downloaded 08/09/2016, https://www.epa.gov/aqs/

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 volitale 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 usually 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 1-Hour Standard in 2008 and attainment of the 1997 8-Hour standard in 2015.

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 concentrations are formed from precursors of nitrogen oxide (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), and ammonia (NH3). This figure shows how much precursor emissions have decreased from 2005 to attainment of the PM2.5 24-hour standard in 2012.  Emissions are expected to continue to decline 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. 

Supporting Page
Back to Top