California Air Resources Board

                                                                                                                                                                                            < BACK TO CURRENT ACTIVITIES

CARB has conducted light-duty surveillance programs since the 1970’s to solicit and procure a representative sample of the in-use fleet to collect emissions data that is used to update the CA emissions inventory models. The primary objective of a surveillance program is to collect emissions data that represent the in-use fleet. The data is used to update the current EMisson FACtor model (EMFAC) on a continual basis. This program tests passenger cars and trucks at CARB’s Southern California laboratory. Motor vehicle exhaust and evaporative emissions are measured and analyzed to support emissions inventory improvement and better understand the emission trends due to new vehicle technologies, populations and driving activity.

The current LDVSP is a three-year project and will begin in the fall of 2023. The collected test data will be used to evaluate engine start emissions (after varied periods of soak) and running exhaust emissions. Data collected from evaporative tests will be used to evaluate hot soak, diurnal, running loss and permeation emission factors used in the model. Additional testing over arterial and freeway driving cycles will help evaluate and update the model’s light-duty vehicle speed correction factors. This program also includes on-road emissions testing using portable emissions measurement systems (PEMS).

Special testing of vehicles under varying outside ambient temperatures at different relative humidity settings with the air conditioning on and off will be used to develop temperature, RH and AC correction factors used in the model. Particulate matter (PM) and speciated emissions data will be collected to support air quality planning. Additionally, the collection of ammonia (NH₃) data from exhaust emissions testing will be used to update the model.

If you have questions, please contact the LDVSP Project Engineer, Steven Magbuhat (steven.magbuhat@arb.ca.gov) at (951) 542-3275 or Section Manager, Satya Sardar (satya.sardar@arb.ca.gov) at (951) 542-3376.