AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Spatial Distribution of and Correlation between Noise And Particulate Matter near Two Freeways in Los Angeles, California
SHI SHU, Yang Pu, Yifang Zhu, UCLA
Abstract Number: 378 Working Group: Urban Aerosols
Abstract Near-freeway environments are important from public health and environmental justice perspectives. Because both the traffic emitted air pollution and noise are associated with cardiovascular disease, there is a knowledge gap on how they distributed in space and if they are correlated with each other. This study investigated the spatial profile of particle concentrations and noise levels near Interstate 405 and Interstate 710, two major freeways in Los Angeles, CA. Besides ultrafine particle (UFP) number concentrations and fine particle (PM2.5) mass concentrations, A-weighted equivalent continuous sound level (LeqA) was measured simultaneously at increasing distances from the freeways on four streets with or without sound wall. Twenty sampling sessions were conducted on nine different days from February to June 2013. For the 405 site, the sampling sessions were scheduled at different hours of daytime to cover different traffic and meteorological conditions. For the 710 site, the sampling sessions were scheduled during both daytime and nighttime to capture different meteorological conditions. Generally, LeqA levels showed a more symmetrical profile on both sides of freeways than particulate matter concentrations did. Under upwind conditions, UFP showed relatively low concentrations and no obvious gradient, while LeqA showed decay with increasing distance as it did under downwind conditions. Moderate correlations (Pearson correlation coefficients ranged from 0.39 to 0.72) between LeqA and UFP were observed under downwind conditions on all four streets. The presence of a sound wall was found to effectively reduce LeqA but not UFP and PM2.5. Both the LeqA level and UFP concentrations at a fixed location increased with increased traffic volume, but at different rate. These data may be used to study the independent and synergistic health impacts of noise and air pollutants near roadways.