Application of a multi-lag regression approach to determine on-road PM10 and PM2.5 emission rates

Intensive measurements were performed at roadside locations in Reno, Nevada, and Durham/Research Triangle Park, North Carolina to derive mass emission factors from on-road vehicles. Measurements included continuous particulate matter (PM) concentrations (PM2.5, and PM10), wind speed, wind direction, and vehicle number, class, and speed. A multi-lag linear regression approach was applied to calculate mass emission rates using the continuous data. The output of the multi-lag regression model, the regression coefficients, along with the vehicle specifications and the wind speed/direction at each site were then used to calculate mass emission factors for light-duty spark ignition (LDSI) and heavy-duty diesel (HDD) vehicles. PM10 emission factors ranged from 530 to 9100 mg/km, and from 90 to 850 mg/km for HDD and LDSI vehicles, respectively. PM2.5 emission factors ranged from 120 to 170 mg/km, and from 10 to 90 mg/km for HDD and LDSI vehicles, respectively.