About Risk Trend Maps

This page last reviewed August 17, 2010

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This page contains a brief description of what is included on the risk trend maps viewing page. To return to the trend maps, press "Return to Map Page", above.

Overview

The risk trend maps viewing page allows the selection of inhalation cancer risk maps for: 1990; 2001; 2010 with currently adopted controls; and, finally, the risk maps where additional diesel controls (beyond those adopted circa 2001) in place to achieve the goal of a 75% reduction in diesel cancer inhalation risk from year 2000 levels.

Maps for 2001

The 2001 maps are the same as the total risk maps from the summary map viewer, which were derived mostly from year 2001 data.

1990 Maps and 2010 Adopted Rule Maps

The 1990 and the projected 2010 risk maps use the same data as the 2001 risk maps with the following exceptions:
  1. The major diesel source emissions were scaled to 1990 and projected 2010 emissions (reflecting currently adopted controls);
  2. The major onroad and offroad mobile source risk drivers, such as benzene and 1,3-butadiene emissions, were also scaled to 1990 and 2010 levels. These pollutants/sources account for most of the inhalation cancer risk from the pollutants/sources included in this analysis.

Maps Meeting Goal of 75 Percent Reduction in Diesel Risk From 2000

The risk maps that include the additional controls to achieve the 75% reduction goals use the same data as the adopted control 2010 risk maps, but in this case the diesel emissions reflect a reduction by 75% in diesel risk from year 2000 levels.

What Sources are Driving Risk Trends?

These trend maps demonstrate the large influence of diesel emissions on the overall risk picture and the effects of current and projected controls for diesel engines. They also incorporate smaller, though still important, risk reductions from the decreases in onroad and offroad nondiesel emissions. Although these trend maps incorporate much of the region-wide inhalation cancer risk that current science predicts is present, these trend maps do not take into account the reductions in other risk producing compounds, and sources, between 1990 and 2010. To view trends in ambient monitored levels for other compounds please visit the toxic trends site.

Overall Risk Trend and Risk Reduction Goal 

The overall risk trend is clearly down. However, comparing the projected 2010 maps reflecting currently adopted controls to the maps that result from the achievement of the 75% diesel emissions reduction goal demonstrates the importance of the additional control programs.

Please send questions or comments to: 
eibweb@arb.ca.gov


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