01698058

Component

Near-road air quality measurement serves as a fundamental method to understand the impact of transportation emissions on ambient air quality and public health. In this study, the authors obtained 5-minute average fine particulate matter (PM₂.₅) and nitrogen dioxide (NO₂) measurement data from two near-freeway air monitoring stations (AMS) in Southern California. In addition, they collected 13 variables and more than 26,000 rows of data, including weather parameters, traffic speed, and traffic volume near the AMS. The authors applied Multiple Linear Regression (MLR) and Multivariate Adaptive Regression Splines (MARS) models to examine the relationship among the weather parameters, traffic data, and near-freeway air pollutant concentration. Both MLR and MARS showed that all weather parameters (e.g., relative humidity, pressure, temperature, wind) were significant variables. MLR coefficients indicated that the traffic speed on the direction closest to the AMS had up to 13 times larger impact than the speed on the opposite direction. For State Route 60 AMS, MLR gave the adjusted R² as 0.18 and 0.27 for PM₂.₅ and NO₂, respectively, and MARS gave the R² as 0.30 and 0.46, respectively. For Interstate-710 AMS, MLR gave the adjusted R² as 0.14 and 0.36 for PM₂.₅ and NO₂, respectively, and MARS gave the R² as 0.21 and 0.57. Generally, NO₂ concentration can be better explained by the selected variables than PM₂.₅. The test of traffic speed segmentation further indicates that the traffic speed has a considerable influence on near-road pollutant concentrations.

This paper was sponsored by TRB committee ADC20 Standing Committee on Transportation and Air Quality.

19-03343

English

7p

2019

Transportation Research Board 98th Annual Meeting

Digital/other

Photos; References; Tables

Air quality; Data analysis; Data collection; Environmental monitoring; Freeways; Pollutants; Public health; Traffic data; Weather

Environment; Highways

Transportation Research Board Annual Meeting 2019 Paper #19-03343

TRIS, TRB, ATRI

Dec 7 2018 9:45AM