EFFECTS OF ENGINE IDLING ON NAAQS CRITERIA POLLUTANT EMISSIONS FROM NONROAD DIESEL CONSTRUCTION EQUIPMENT

摘要

effects of engine idling on air pollutant emissions from highwayconstruction equipment due to a lack of combined activity and emissions data. This paperpresents a methodology for quantifying the impact of idling on National Ambient Air QualityStandards (NAAQS) criteria pollutant emissions, including nitrogen oxides (NO_x), carbonmonoxide (CO), hydrocarbons (HC), and particulate matter (PM). The methodology and resultsare based on field data collected from 35 items of nonroad diesel construction equipment.Engine idle time was quantified in terms of equipment operational efficiency (η), which wasdefined as the ratio of non-idle time to total equipment use time (non-idle time plus idle time).Using η and the ratio of idle to non-idle emission rates (r_e) for each pollutant, the percentageincrease in the total quantities of each pollutant emitted (N_E) were calculated for each item ofequipment for the observed values of η and r_e. Results showed that as η increased (or idle timedecreased), N_E decreased. Mathematical models using η as a predictor variable were developedto estimate values of N_E for each pollutant. Regression equations in the form of y =ax~3+bx~2+cx+d were developed for NO_x and HC, with R~2 values of 97% and 87%, respectively.Regression equations in the form of y = mx+b were developed for CO and PM, with R~2 values of50% and 65%, respectively. Recommendations include using the models as performancemeasurement tools to assess idle restriction regulations and operational strategies of highwayconstruction equipment.