published journal article
published journal article
PM2.5 is an air contaminant that has been widely associated with adverse respiratory and cardiovascular health, leading to increased hospital admissions and mortality. Following concerns reported by workers at an industrial facility located in Santa Ana, California, workers and community leaders collaborated with experts in the development of an air monitoring pilot study to measure PM2.5 concentrations to which employees and local residents are exposed during factory operating hours. To detect PM2.5, participants wore government-validated AtmoTube Pro personal air monitoring devices during three separate workdays (5 AM–1:30 PM) in August 2021. Results demonstrated a mean PM2.5 level inside the facility of 112.3 µg/m3, nearly seven-times greater than outdoors (17.3 µg/m3). Of the eight workers who wore personal indoor sampling devices, five showed measurements over 100 μg/m3. Welding-related activity inside the facility resulted in the greatest PM2.5 concentrations. This study demonstrates the utility of using low-cost air quality sensors combined with employee knowledge and participation for the investigation of workplace air pollution exposure as well as facilitation of greater health-related awareness, education, and empowerment among workers and community members. Results also underscore the need for basic measures of indoor air pollution control paired with ongoing air monitoring within the Santa Ana facility, and the importance of future air monitoring studies aimed at industrial facilities.
published journal article
published journal article
Mobility is one mechanism used to address the federal goals of deconcentrating poverty and minorities. The Housing Choice Voucher Program relies on participants to make residential location decisions consistent with these goals. Our research investigates the level and impact of mobility on the neighborhood quality of voucher holders, their neighborhood conditions by race and ethnicity, and perceived obstacles to mobility within the jurisdiction of a Southern California housing authority. About one-third of the sample moved during the study, and moving resulted in improved neighborhoods for only one subset of movers. Minorities live in more impoverished, overcrowded neighborhoods than nonminorities, even when controlling for mobility status, contract rent, and other factors. Further, most voucher holders see the lack of rental units as a major obstacle to mobility. These findings suggest that current policy is not uniformly achieving deconcentration and that real and perceived barriers to mobility exist, especially for minorities.
published journal article
book/book chapter
This book presents a history of the United States freeway system especially as it relates to cities and urban planning. The roles played by transportation professionals and others, such as government officials, are explored. The impacts of changes in legislation, funding, and environmental policy are outlined. Three case studies of freeway development are included: Syracuse, New York; Los Angeles, California; and Memphis, Tennessee. Chapter topics include: America’s changing cities; The 1930s; National policy, 1939-1945; Postwar urban freeways; and Changing visions and regulations.
published journal article
A discrete choice model is presented that explicitly recognizes differences in the error structure associated with a single `’oddball” alternative within the choice set that has properties not common to the other alternatives. The model purportedly resolves questions related to the use of alternative-specific variables in transportation choice models to capture the effects of attributes unique to a single travel alternative, such as `’schedule frequency” in the case of modal choice between personal auto and public transit. The model, which shares the general error structure of multinomial legit, is shown to be a modification of a multinomial legit subchoice by terms involving the exponential integral. The model is shown to yield different results from those produced by an equivalent multinomial legit specification. Comparisons to multinomial probit and nested legit formulations are also made.
published journal article
Skin diseases have become a global concern. This study aims to evaluate the associations between ambient air pollution and emergency room visits for skin diseases under the background of improving air quality in China. Based on 45,094 cases from a general hospital and fixed-site monitoring environmental data from 2014–2019 in Beijing, China, this study used generalized additive models with quasi-Poisson regression to estimate the exposure–health associations at lag 0–1 to lag 0–7. PM2.5 and NO2 exposure were associated with increased emergency room visits for total skin diseases (ICD10: L00-L99). Positive associations of PM2.5, PM10, O3 and NO2 with dermatitis/eczema (ICD-10: L20–30), as well as SO2 and NO2 with urticaria (ICD-10: L50) visits were also found. For instance, a 10 μg/m3 increase in PM2.5 was associated with increases of 0.7% (95%CI: 0.2%, 1.2%) in total skin diseases visits at lag 0–5 and 1.1% (95%CI: 0.6%, 1.7%) in dermatitis/eczema visits at lag 0–1, respectively. For PM2.5, PM10 and CO, stronger annual associations were typically observed in the high-pollution (2014) and low-pollution (2018/2019) years. For instance, a 10 μg/m3 increase in PM2.5 at lag 0–5 was associated with increases of 1.8% (95%CI: 1.0%, 2.6%) and 2.3% (95%CI: 0.4%, 4.3%) in total skin disease visits in 2014 and 2018, respectively. Our study emphasizes the necessity of controlling the potential health hazard of air pollutants on skin, although significant achievements in air quality control have been made in China.
conference paper
published journal article
During the last five years, transit performance indicators have been widely used in the transit industry. California and New York have used performance indicators to determine eligibility for funding. In Pennsylvania, transit performance measures have been used to provide incentive payments for superior performance, and in Michigan a detailed analysis of transit operations provides the basis for state managerial assistance. In Los Angeles County, nine transit operators, including Southern California Rapid Transit District, provide fixedroute transit service. Between 1977 and 1980, operating cost per vehicle hour increased from $28.52 to $38.76, a rate higher than the consumer price index for the Los Angeles area. In response to state legislation designed to maximize utilization of public subsidies for transit, the Los Angeles County Transportation Commission undertook the development of performance-based guidelines for allocating transit subsidies. The performance guidelines developed in cooperation with the local transit operators are presented here. In this program, service is classified into local and express categories. Seven indicators were chosen to monitor transit performance on a periodic basis. Three indicators were selected to establish standards to be achieved by all fixed-route service operators in Los Angeles County. Compliance with these standards will determine eligibility for discretionary funds (representing 5 percent of operating assistance) in the future. The methodology for quantifying loss of subsidy funds if an operator falls below the established standards is also described. The performance guidelines merit consideration for two reasons. First, they represent an attempt by a large metropolitan area to control transit costs, and second they initiate performance-based funding allocation rather than funding based on demographic characteristics or operating deficits. Both reasons are substantial advancements in the theory and application of performance-based guidelines to transit-financing issues.