Goals of ISR
The purpose of the District's Indirect Source Review (ISR) Program is to reduce emissions of NOx
and PM10 from new development projects. In general, new development contributes to the air-pollution
problem in the Valley by increasing the number of vehicles and vehicle miles traveled.
In 2005, on-road vehicles generated approximately 200 tons per day of NOx and direct PM10
pollution in the Valley. Although newer, cleaner technology is reducing the per-vehicle
pollution, the emissions increase from new development putting more vehicles on Valley roads
partially offsets the emission reductions gained from technology advances.
Indirect Source Review applies to development projects that have not yet gained
discretionary approval. A discretionary permit is a permit from a public agency,
such as a city or county, that requires some amount of deliberation by that agency,
including the potential to require modifications or conditions on the project.
However, there are several sources that are exempt. These include transportation
projects that meet certain conditions; reconstruction projects that result from a
natural disaster; development projects whose primary functions are from District
permitted stationary sources. Also, development projects that have a mitigated
baseline below 2.0 tons per year for NOx and PM10 are exempt from the mitigation
requirement of the rule.
The ISR Rule (Rule 9510) and the Administrative ISR Fee Rule (Rule 3180)
are the result of state requirements outlined in the California Health and
Safety Code, Section 40604 and the State Implementation Plan (SIP). The
District’s SIP commitments are contained in the District’s 2003 PM10 Plan
and Extreme Ozone Attainment Demonstration Plan (Plans), which identify
the need to reduce PM10 and NOx in order to reach the ambient air-pollution
standards on schedule. The Plans identify growth and reductions in
multiple source categories. The Plans quantify the reduction from current
District rules and proposed rules, as well as state and federal
regulations, and then model future emissions to determine if the
District may reach attainment for applicable pollutants.
The PM10 and Ozone plans have determined that the ISR Rule,
in addition to existing and future rules and conditions, will
help clean the Valley’s air and reach attainment.