On-Roadway In-Cabin Exposure to Particulate Matter: Measurement Results Using Both Continuous and Time-Integrated Sampling Approaches

Abstract

The Atlanta Commuters Exposure (ACE) Study was designed to measure in-cabin exposure to roadway particulate pollution and acute health response in a panel of adults with and without asthma following a 2-h scripted route along major highways in Atlanta. This article focuses on methods and results of both continuous and integrated approaches used to measure the concentration of PM 2.5 mass, particle number concentration (PNC), black carbon (BC) mass, and particle-bound PAHs, in-cabin noise, PM elemental composition, elemental carbon, organic carbon, water-soluble organic carbon (WSOC) content, and speciation of a broad range of organic compounds including alkanes, hopanes, and PAHs. Speciated PM data indicates that in-cabin particles derive from three non-co-varying processes: the resuspension of road dust containing crustal elements and previously-deposited brake pad residue with a contribution of normal fuel combustion, incomplete combustion processes producing PAHs and carbon particles, and particles ablated from brake pads that have not previously deposited to the roadside environment. Most in-cabin pollutants were elevated during the warm season with the notable exception of PNC. PNC was not found to be correlated with most other pollutants. In-cabin concentrations were marginally higher when windows were open.

Exposure to traffic pollution, acute inflammation and autonomic response in a panel of car commuters

“…All collected data were assessed for bias, precision and completeness. Full details on the data quality parameters for all of the measured pollutants can be found elsewhere (Greenwald et al 2014). …”

Modification of Traffic-related Respiratory Response by Asthma Control in a Population of Car Commuters

“…Additional description of the concentrations of these in-vehicle pollutants have been published previously. 2 …”

“…Pollutant data collection protocols, analytic methods, and data quality have been described in detail elsewhere. 2,6 A previously published matrix of Pearson correlation coefficients indicating correlations of the in-vehicle particulate components 6 also provides information about correlations in the data used for this analysis.…”

“…Percentage of predicted values of FEV 1 , FVC, and FEF 25–75 were calculated using standard reference equations published by Hankinson et al 7 We measured exhaled NO, malondialdehyde, and spirometry precommute, immediately postcommute, and 1, 2, and 3 hours after the commute using methods described previously. 2,6 …”

“…1 In-vehicle measurements of organic and inorganic particulate matter components indicate that drivers and passengers are exposed to exhaust, regardless of whether they use vehicle air filters or drive with the windows closed. 2 The effects of traffic-related air pollution on respiratory health, including on respiratory health of individuals with asthma, are well documented. 3-5 However, little information is available about the contribution of asthma to individual susceptibility or whether any such susceptibility may be affected by level of asthma control.…”