Particle Concentrations in Urban Microenvironments

Levy, Jonathan I.; Houseman, E. Andrés; Ryan, Louise; Richardson, Deborah; Spengler, John D.

doi:10.2307/3434958

Cited by 35 publications

(17 citation statements)

References 24 publications

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“…In order to compare the PM 2.5 exposure between indoor and outdoor microenvironments, some studies have measured this pollutant simultaneously in both microenvironments (Brauer et al, 2000;Levy et al, 2000;Rojas-Bracho et al, 2000). Since in this work PM 2.5 real-time personal measurements were obtained, measurements at indoor and outdoor microenvironments were not paired by time, and indoor and outdoor measurements were grouped independently of the day time.…”

Section: Study Considerations and Limitationsmentioning

confidence: 99%

“…This allowed us to identify the microenvironment without recall bias, although microenvironment classification errors could be introduced by the participants. Other studies assigned activities to the participants into different microenvironments (Levy et al, 2000), or interviewed the study subjects in order to identify the microenvironments in which they stayed during the whole recording period (Brauer et al, 2000). Preassigned activities avoid microenvironment misclassification, but do not allow the assessment of the real exposure during activities on an ordinary day.…”

Section: Study Considerations and Limitationsmentioning

confidence: 99%

“…Most health effects studies on exposure to particulate matter air pollution have been carried out during short periods of time and using ambient monitors (Dockery et al, 1993;Pope et al, 1995;Saldivar et al, 1995;Ostro et al, 1996;Simpson et al, 1997;Brauer et al, 2000;Levy et al, 2000). Studies carried out in Mexico City were also performed with ambient monitors, and in some cases with monitors from the environmental monitors network (Romieu et al, 1992(Romieu et al, , 1996Borja-Aburto et al, 1997;Gold et al, 1999;Loomis et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Personal exposure to particulate matter less than 2.5 μm in Mexico City: a pilot study

Vallejo

Lerma

Infante

et al. 2004

J Expo Sci Environ Epidemiol

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This study was aimed to describe the personal exposure of permanent residents in Mexico City's Metropolitan Area (MCMA) to particulate matter of less than 2.5 mm diameter (PM 2.5 ) during their daily activities. A total of 40 healthy volunteers (30 women and 10 men) with sedentary activities were included. All of them carried a PM 2.5 personal monitor during 13 h and registered their activities in a written diary that classified them in indoor and outdoor microenvironments in each 30 min period. All sample collections started at 0900 hours, and even though measurements were obtained during the rainy season (April-August 2002), the relative humidity was less than 70%. The data were categorized and evaluated under the following criteria: morning and afternoon exposure, indoor and outdoor activities, and geographical location. The descriptive analysis showed that the overall outdoor median concentration of PM 2.5 (89.50 mg/m 3 ) was higher than the indoor one (67.55 mg/m 3 ). PM 2.5 concentrations in the morning to early afternoon were more elevated than in the late afternoon, suggesting a circadian-like behavior. In the indoor microenvironment, the highest concentration occurred in the subway (106.2 mg/m ). All the differences were statistically significant (Po0.05). Multivariate analysis corroborated that PM 2.5 concentrations are mainly determined by geographical locations and hour of the day, but not by the type of microenvironment. The inclusion of covariables in the multivariable analysis ensures a more accurate estimation and prediction of the real PM 2.5 concentrations. In conclusion, PM 2.5 personal exposure of healthy adult permanent residents of MCMA is usually higher than recommended by the international standards in outdoor and even in indoor microenvironments. Particulate matter personal exposure varies in relation to hour of the day, daily activities and microenvironments.

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Section: Study Considerations and Limitationsmentioning

confidence: 99%

Section: Study Considerations and Limitationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Personal exposure to particulate matter less than 2.5 μm in Mexico City: a pilot study

Vallejo

Lerma

Infante

et al. 2004

J Expo Sci Environ Epidemiol

View full text Add to dashboard Cite

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“…Dispersion models have also been used to estimate exposure because they incorporate both spatial and temporal variations in pollutant concentration; however, dispersion models require resource-intensive meteorological and emissions data to make accurate predictions (Briggs et al, 1997;Jerrett et al, 2005). Land use regression (LUR) modeling has emerged as a cost-effective alternative approach to meet these challenges of assessing the intra-urban spatial variability of ambient air pollutants in urban and industrial settings because it can capture local-scale spatial variations more effectively and economically than previous monitoring and modeling approaches Levy et al, 2000;Jerrett et al, 2005;Brauer et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Personal and household-level monitoring provide more accurate measures of exposure (Levy et al, 2000), but the suitability of individual monitoring for estimating exposure in epidemiologic studies is hampered by the high cost and participant burden associated with air monitoring data collection, particularly for a large cohort (Madsen et al, 2007). Dispersion models have also been used to estimate exposure because they incorporate both spatial and temporal variations in pollutant concentration; however, dispersion models require resource-intensive meteorological and emissions data to make accurate predictions (Briggs et al, 1997;Jerrett et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Assessing the spatial distribution of nitrogen dioxide in London, Ontario

Oiamo

Luginaah

Buzzelli

et al. 2012

Journal of the Air & Waste Management Association

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Land use regression (LUR) models have been widely used to characterize the spatial distribution of urban air pollution and estimate exposure in epidemiologic studies. However, spatial patterns of air pollution vary greatly between cities due to local source type and distribution. London, Ontario, Canada, is a medium-sized city with relatively few and isolated industrial point sources, which allowed the study to focus on the contribution of different transportation sectors to urban air pollution. This study used LUR models to estimate the spatial distribution of nitrogen dioxide (NO 2 ) and to identify local sources influencing NO 2 concentrations in London, ON. Passive air sampling was conducted at 50 locations throughout London over a 2-week period in May-June 2010. NO 2 concentrations at the monitored locations ranged from 2.8 to 8.9 ppb, with a median of 5.2 ppb. Industrial land use, dwelling density, distance to highway, traffic density, and length of railways were significant predictors of NO 2 concentrations in the final LUR model, which explained 78% of NO 2 variability in London. Traffic and dwelling density explained most of the variation in NO 2 concentrations, which is consistent with LUR models developed in other Canadian cities. We also observed the importance of local characteristics. Specifically, 17% of the variation was explained by distance to highways, which included the impacts of heavily traveled corridors transecting the southern periphery of the city. Two large railway yards and railway lines throughout central areas of the city explained 9% of NO 2 variability. These results confirm the importance of traditional LUR variables and highlight the importance of including a broader array of local sources in LUR modeling. Finally, future analyses will use the model developed in this study to investigate the association between ambient air pollution and cardiovascular disease outcomes, including plaque burden, cholesterol, and hypertension.

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Urban aerosol particulates on Hong Kong roadsides: size distribution and concentration levels with time

2011

Stoch Environ Res Risk Assess

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A detailed study on particulate matter from vehicle emission was carried out at roadsides in Hong Kong downtown area. The study aims to explore the variations of particulate matter at roadsides in morning and afternoon. Data of concentrations of different size groups of particulate matter were collected and analyzed. It was found that the particulate levels generally vary periodically with traffic signal changes. During the green traffic light period, concentrations of the particulate matter increase to peak point and then diffuse to a relatively stable level in the red traffic light period. Such stable level is regarded as background level, to which pedestrians are exposed when they walk-by and cross the zebra zones. To analyze and further explore the collected data, a statistical distribution model, i.e., goodness-of-fit test, was employed. It was noticed that the lognormal distribution best fits the particulate matter data in both morning and afternoon. In addition, the non-parametric test was also used to assess the differences between morning and afternoon data. The results show that both data sets statistically differ from each other at 5% significance level. It can be deduced that the change of traffic volume, humidity and wind speed between morning and afternoon may cause this difference.

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Particle Concentrations in Urban Microenvironments

Cited by 35 publications

References 24 publications

Personal exposure to particulate matter less than 2.5 μm in Mexico City: a pilot study

Personal exposure to particulate matter less than 2.5 μm in Mexico City: a pilot study

Assessing the spatial distribution of nitrogen dioxide in London, Ontario

Urban aerosol particulates on Hong Kong roadsides: size distribution and concentration levels with time

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