Influence of traffic patterns on particulate matter and polycyclic aromatic hydrocarbon concentrations in Roxbury, Massachusetts

Abstract

Vehicle emissions have been associated with adverse health effects in multiple epidemiological studies, but the sources or constituents responsible have not been established. Characterization of vehicle-related exposures requires detailed information on spatial and temporal trends of various pollutants and the ability to predict exposures in unmonitored settings. To address these issues, in the summer of 2001 we measured continuously particle-bound polycyclic aromatic hydrocarbons (PAHs), ultrafine particles, and PM 2.5 at a number of sites in Roxbury, a neighborhood of Boston, Massachusetts with significant diesel and gasoline-fueled traffic. We took measurements at the side of the road and at varying distances from the road, with simultaneous collection of traffic counts and meteorological conditions. Across all nine sites, median roadside concentrations were 8 ng/m 3 of particle-bound PAHs (range: 4-57), 16,000 ultrafine particles/cm 3 (range: 11,000-53,000), and 54 mg/m 3 of PM 2.5 as measured with a DustTrak (range: 12-86). Concentrations of all pollutants were lower at greater distances from the road, upwind, and at higher wind speeds, with greater concentration gradients for PAHs and ultrafine particles. In linear mixed effects regression models accounting for temporal autocorrelation, large diesel vehicle counts were significantly associated with roadside concentrations of PAHs (P ¼ 0.02), with a moderate association with ultrafine particles and little relation with PM 2.5 . Although more comprehensive information would be needed for epidemiological applications, these data demonstrate significant spatial and temporal heterogeneity for traffic-related pollutants during the summer in an urban center, with our monitoring and analytical methodology helping to inform source attribution.

Determinants of ultrafine particle exposures in transportation environments: findings of an 8-month survey conducted in Montréal, Canada

“…However, we were unable to identify other studies exploring the effects of ambient temperature and wind speed on UFP exposures in transportation environments. Nevertheless, previous studies have observed inverse relationships between wind speed and roadside UFP levels (Zhu et al, 2002(Zhu et al, , 2006aLevy et al, 2003) as well as between temperature and ambient UFP counts (Jeong et al, 2004(Jeong et al, , 2006 and therefore our results appear to be consistent with previous findings. Indeed, lower UFP exposures were expected at increased wind speeds owing to the dispersion of vehicular emissions, and the observed inverse correlation between ambient temperature and UFP exposures was not surprising as the formation of UFPs from traffic exhaust depends in part on vapor condensation (Korhonen et al, 2004;Kulmala et al, 2004) which is favored at lower temperatures.…”

“…Diesel school buses and coach passenger buses were identified as strong local sources of UFPs while walking and driving, respectively, and this observation is consistent with previous findings (Abraham et al, 2002;Levy et al, 2003;Westerdahl et al, 2005). Interestingly, UFP exposures on public transit buses in Montre´al were more than twice those reported for diesel school buses in Fredericton, New Brunswick (Health Canada, 2005); suggesting that traffic density likely (expected to be lower in Fredericton than in Montre´al) plays an important role in determining in-vehicle exposures.…”

Using a generalized additive model to quantify the influence of local meteorology on air quality in Zagreb

“…Wind speed and direction have a large effect on CO, NO 2 and PM 10 , a pattern also found elsewhere (e.g. Levy et al, 2003). Both precipitation variables have some importance for PM 10 but have little effect on the other three pollutants.…”

“…Finlayson-Pitts and Pitts, 1986;Levy et al, 2003;Aldrin and Haff, 2005;Hussein et al, 2006;Cheng et al, 2007;Prtenjak et al, 2009Prtenjak et al, , 2013Klaić et al, 2012Klaić et al, , 2015. Past investigations focusing on the interplay between meteorology and air quality in Croatia can be grouped as follows: 1) Modelling of the long-range transport of airborne pollutants.…”

Exposure of Children to Ultrafine Particles in Primary Schools in Portugal

“…In addition, children tend to be more susceptible to UFP toxicity when compared to adults, particularly due to their undeveloped immune and respiratory systems (Schwartz 2004;Foos et al, 2008). Ultrafine particles may originate outdoors, from vehicle emissions and gas-to-particle conversions (Levy et al, 2003;Vigotti et al, 2007). However, indoor UFP originate from a wide range of indoor sources and occupant-related activities such as cooking, smoking, cleaning, and painting (Wallace et al, 2002;Vinzents et al, 2005;Weichenthal et al, 2007).…”