Philadelphia Metropolitan Area Research Articles

An ozone episode in the Philadelphia metropolitan area

In July and August 1999 a Northeast Oxidant and Particle Study field campaign was conducted in the Philadelphia metropolitan area to determine causes for episodically high levels of O3 and particulate matter ≤2.5 μm in aerodynamic diameter. We report emission estimates, weather information, surface O3 monitoring data, and aircraft observations, with a focus on 31 July, the last day of an O3 episode in which concentrations in Philadelphia reached 165 ppb, the highest level observed there in the past 11 years. As is common in the northeastern states, this O3 episode started with the development of a broad ridge over the central United States and ended with the northeast corridor under the influence of an Appalachian lee trough with airflow from the SW in an along‐corridor direction. For a portion of the morning of 31 July, winds were nearly stagnant, allowing local emissions to accumulate. In contrast to typical O3 episodes in the northeast, transport on 31 July was limited, and O3 hot spots occurred close to NOx and volatile organic compound (VOC) emission sources. High O3 was observed downwind of Baltimore and Philadelphia, both major urban areas. High O3 was also observed in a less likely region near the Delaware‐Pennsylvania border, downwind of Wilmington, Delaware, but near utility and industrial emission sources. Surface O3 monitoring data and morning aircraft observations show that the residual layer aloft contained 80–100 ppb of O3 but almost no O3 precursors. Same‐day photochemistry on 31 July caused surface O3 concentrations to increase by 60–80 ppb. Photochemical model calculations indicate O3 production rates in excess of 20 ppb h−1 in regions with NOx > 5 ppb. High NOx concentrations are a consequence of poor ventilation. Peroxide observations and calculations indicate that O3 production is VOC limited in the high‐NOx portions of the Philadelphia urban plume. Our results are contrasted against a severe O3 episode that occurred in 1995. While the 1999 episode had stagnation conditions leading to local O3 hot spots, there were mesoscale meteorological features in 1995 that favored interregional transport.

A Spatial Mixture Model of Innovation Diffusion

The diffusion of new product or technical innovation over space is here modeled as an event‐based process in which the likelihood of the next adopter being in region r is influenced by two factors: (i) the potential interactions of individuals in r with current adopters in neighboring regions, and (ii) all other attributes of individuals in r that may influence their adoption propensity. The first factor is characterized by a logit model reflecting the likelihood of adoption due to spatial contacts with previous adopters, and the second by a logit model reflecting the likelihood of adoption due to other intrinsic effects. The resulting spatial diffusion process is then assumed to be driven by a probabilistic mixture of the two. A number of formal properties of this model are analyzed, including its asymptotic behavior. But the main analytical focus is on statistical estimation of parameters. Here it is shown that standard maximum‐likelihood estimates require large sample sizes to achieve reasonable results. Two estimation approaches are developed which yield more sensible results for small sample sizes. These results are applied to a small data set involving the adoption of a new Internet grocery‐shopping service by consumers in the Philadelphia metropolitan area.

A Spatial Mixture Model of Innovation Diffusion

The diffusion of new product or technical innovation over space is here modeled as an event-based process in which the likelihood of the next adopter being in region r is influenced by two factors: (i) the potential interactions of individuals in r with current adopters in neighboring regions, and (ii) all other attributes of individuals in r that may influence their adoption propensity. The first factor is characterized by a logit model reflecting the likelihood of adoption due to spatial contacts with previous adopters, and the second by a logit model reflecting the likelihood of adoption due to other intrinsic effects. The resulting spatial diffusion process is then assumed to be driven by a probabilistic mixture of the two. A number of formal properties of this model are analyzed, including its asymptotic behavior. But the main analytical focus is on statistical estimation of parameters. Here it is shown that standard maximum-likelihood estimates require large sample sizes to achieve reasonable results. Two estimation approaches are developed which yield more sensible results for small sample sizes. These results are applied to a small data set involving the adoption of a new Internet grocery-shopping service by consumers in the Philadelphia metropolitan area.

Maternal discussions about pregnancy and adolescents, attitudes toward pregnancy

Purpose To identify aspects of maternal-adolescent relationships that are associated with high ambivalence toward pregnancy. Methods This was a cross-sectional study of 350 inner-city, African-American females between the ages of 14 and 17 years residing in the Philadelphia metropolitan area. Adolescent females and their resident female caretaker (usually the biological mother) were both interviewed. Multiple regression analyses were used to predict adolescents’ pregnancy attitudes from maternal-adolescent discussions about pregnancy, perceived maternal disapproval of pregnancy, and relationship satisfaction. Results Greater levels of discussion about negative consequences of pregnancy, stronger levels of perceived maternal disapproval, and higher levels of satisfaction all were associated with more negative attitudes towards pregnancy on the part of the adolescent. Conclusions Maternal communication about the negative consequences of experiencing a pregnancy and the quality of the mother–daughter relationship more generally may impact on adolescent attitudes toward pregnancy.

The Perils of Healthcare Workforce Forecasting: A Case Study of the Philadelphia Metropolitan Area

In 1996, a widely circulated and influential forecast for the Philadelphia Metropolitan Area stated that a decline in hospital and healthcare employment in the region would occur over the next five years. It also suggested that this decline would exacerbate the problem of an oversupply of nurses seeking hospital employment. The forecast reflected a regional leadership and expert consensus on the impact of the managed care transformation on workforce needs and was supported by short-term statistical trends in regional utilization and employment. Confounding these predictions was the fact that hospital and healthcare employment actually grew. By the end of 2001, hospitals in the region were experiencing problems in recruiting sufficient numbers of nurses, pharmacists, and technicians. The forecast failed to anticipate the impact of a strong regional economy on supply and underestimated the resilience of underlying forces that have driven the long-term growth in healthcare workforce demand. More effective ongoing monitoring can help moderate the fluctuation of workforce shortages and surpluses.

PRACTITIONER APPLICATION: The Perils of Healthcare Workforce Forecasting: A Case Study of the Philadelphia Metropolitan Area

PRACTITIONER APPLICATION: The Perils of Healthcare Workforce Forecasting: A Case Study of the Philadelphia Metropolitan Area

Redlining Redux

There has been a growing body of evidence indicating race-based discrimination in small business lending. However, very little research has examined potential geographic redlining effects. This article measures small businesslending flows to neighborhoods in the Philadelphia metro politan area. It advances previous work by measuring differential credit flows while accounting for variations in the credit scores of small firms. Black tracts receive fewer loans after accounting for firm density, firm size, industrial mix, neighborhood income, and the credit quality of local firms. The findings suggest that federal bank regulators should expand small business lending data to include racial characteristics and application information, in part to help identify potentially discriminating lenders for further investigation. Also, Community Reinvestment Act regulations should pay more attention to the distribution of small business loans, by both race and income of neighborhood.

Use of Black English and Racial Discrimination in Urban Housing Markets

The authors argue that racial discrimination in housing markets need not involve personal contact between agents and renters. Research indicates that Americans can infer race from speech patterns alone, thus offering rental agents an opportunity to discriminate over the phone. To test this hypothesis, the authors designed an audit study to compare male and female speakers of White Middle-Class English, Black Accented English, and Black English Vernacular. The study was conducted during the spring of 1999 in the Philadelphia metropolitan area. The authors found significant racial discrimination that was often exacerbated by class and gender. Poor black women, in particular, experienced the greatest discrimination.

Daily Mortality in the Philadelphia Metropolitan Area and Size-Classified Particulate Matter

ABSTRACT Time-series of daily mortality data from May 1992 to September 1995 for various portions of the seven-county Philadelphia, PA, metropolitan area were analyzed in relation to weather and a variety of ambient air quality parameters. The air quality data included measurements of size-classified PM, SO4 2-, and H+ that had been collected by the Harvard School of Public Health, as well as routine air pollution monitoring data. Because the various pollutants of interest were measured at different locations within the metropolitan area, it was necessary to test for spatial sensitivity by comparing results for different combinations of locations. Estimates are presented for single pollutants and for multiple-pollutant models, including gaseous pollutants and mutually exclusive components of PM (PM2.5 and coarse particles, SO4 2- and non-SO4 2- portions of total suspended particulate [TSP] and PM10), measured on the day of death and the previous day. We concluded that associations between air quality and mortality were not limited to data collected in the same part of the metropolitan area; that is, mortality for one part may be associated with air quality data from another, not necessarily neighboring, part. Significant associations were found for a wide variety of gaseous and particulate pollutants, especially for peak O3. Using joint regressions on peak O3 with various other pollutants, we found that the combined responses were insensitive to the specific other pollutant selected. We saw no systematic differences according to particle size or chemistry. In general, the associations between daily mortality and air pollution depended on the pollutant or the PM metric, the type of collection filter used, and the location of sampling. Although peak O3 seemed to exhibit the most consistent mortality responses, this finding should be confirmed by analyzing separate seasons and other time periods.

A Bayesian VAR Forecasting Model for the Philadelphia Metropolitan Area

Vector-autoregression (VAR) forecast models have been developed for many state economies, including the three states in the Third Federal Reserve District--Pennsylvania, New Jersey, and Delaware. This paper extends that work by developing a Bayesian VAR forecast model for the Philadelphia metropolitan area and the city of Philadelphia.

A predictive index for the flypaper effect

It is well established that lump-sum public grants boost local government spending more than an equivalent increase in private income, the flypaper effect. One shortcoming of the related literature is that it presumes all communities have an identical propensity to consume from an intergovernmental grant. This paper is one attempt to allow for a heterogeneous response. The working conjecture is that government expenditure on administrative overhead is a gauge of voter control over fiscal decisions. High overhead spending implies a lower provision of public services and a stronger role for revenue-maximizing forces in the budget-setting process. As such, the flypaper effect should be more marked in high overhead communities. An overhead index is applied to a sample of Pennsylvania communities in the Philadelphia metropolitan area. It is difficult to understand these governments' spending propensities from various windfall revenues without the help of the overhead index, supportive evidence for this approach. Because overhead data is widely available, the technique here can be used to address important policy questions such as predicting variations in state government responses to the recently created lump-sum welfare grants.

An assessment of the usefulness of the Duke criteria for diagnosing active infective endocarditis.

We evaluated the usefulness of the Duke criteria for diagnosing cases of active infective endocarditis (IE). Patients were identified prospectively over a 3-year period at 54 hospitals in the Philadelphia metropolitan area. Three of us independently reviewed abstracted hospital records and classified 410 patients as definite, probable, or possible cases of IE or as probable noncases. We then applied the Duke criteria to this sample to assess the degree of agreement between our diagnoses and the diagnoses based on these new criteria. Agreement was good to excellent, ranging from 72% to 90%, depending on the case definition used. The sensitivity of the Duke criteria was also good to excellent, varying from 71% to 99%, again depending on case definition used. Specificity was lower (0-89%). We conclude that use of the Duke criteria will result in little underdiagnosis of IE but that it may result in overdiagnosis of IE; therefore, these criteria should be applied prospectively to determine their clinical usefulness.

Ovarian Aging and Hormone Replacement Therapy: Hormonal Levels, Symptoms, and Attitudes of African-American and White Women

OBJECTIVES: To characterize reproductive hormone levels, symptoms, and attitudes related to menopause among healthy, menstruating white and African-American women aged 44 to 49 years. DESIGN: Pilot study; cross-sectional survey. SETTING: Community-based convenience sample of women in the Philadelphia metropolitan area. PARTICIPANTS: Thirty-three African-American and 35 white women. MEASUREMENTS: The survey instrument collected demographic data, medical and reproductive history, health practices and behaviors. It included previously validated function, depression, and quality-of-life instruments, and a Menopause Attitude Scale that included two factors, attitudes toward the menopause and attitudes toward medical therapy. Anthropometric measurements were taken at enrollment, and reproductive hormones and daily symptom logs were followed over two menstrual cycles. MAIN RESULTS: The two groups were comparable in mean age (African-American 46.2 years, white 46.9 years). Serum levels of estradiol, follicle-stimulating hormone, dihydroepiandrosterone-sulfate, and progesterone were comparable. Symptoms were similar in type and frequency. However, the African-American women had significantly more positive attitudes toward menopause, were more likely to rely on family for information about menopause, and were less likely to have been recommended hormone replacement therapy by their physicians. A majority of women in each group expressed satisfaction with the care they had received. CONCLUSIONS: Perimenopausal African-American and white women have different expectations of menopause and the role of medical care in menopause. This bears directly on women's acceptance of hormone replacement therapy. Conclusions are limited by the small sample size and convenience nature of the study population: further work with larger samples is needed to confirm these apparent differences.

Prevalence and Impact of Exposure to Interpersonal Violence Among Suburban and Urban Middle School Students

The purpose of this study was to determine the prevalence of exposure to violence in preadolescent children in communities that vary by family income and to determine patterns of physical symptomatology and communication after exposure to a traumatic event. Two hundred twenty-eight sixth-grade students from a suburban middle school (school A) and 209 sixth-grade students from an urban middle school (school B) in the Philadelphia metropolitan area were surveyed by a group-administered anonymous questionnaire. Two hundred two students (89%) from school A and 200 students (96%) from school B reported knowing someone who had been robbed, beaten, stabbed, shot, or murdered. One hundred twenty-nine students (57%) and 183 students (88%), respectively, witnessed a robbing, beating, stabbing, shooting, or murder. Ninety-one students (40%) and 141 students (67%) had been personally robbed, beaten up, stabbed, shot, or caught in gun cross fire. One hundred thirty-four (59%) and 152 (73%) reported hearing gunfire in their neighborhood. One hundred eighty-eight (82%) and 202 (97%) had at least one positive response in all three categories: knowing a victim, witnessing an event, and being a victim of violence. The proportion of positive responses from school B was significantly greater than the proportion from school A for all of these results. Many students reported symptoms associated with somatization syndromes, depression, and posttraumatic stress disorder; the school B group had significantly more symptoms than the school A group. Both student groups had discussed episodes of witnessing an event or victimization with others, mostly family members and friends, and expressed feelings of fear, anger, sadness, and frustration about these episodes. A very low percentage of the students (from 1% to 8% in the different analyses) consulted a medical or mental health professional. These data support a substantial prevalence or exposure to violence for suburban and, even more dramatically, for urban middle school-aged children. The higher-prevalence group reported a higher incidence of symptoms sometimes seen after traumatic stress. Many students in both groups expressed multiple feelings about their exposure to violence, and most talked to someone about their exposure; rarely was this person a health professional.

Incidence of infective endocarditis in the Delaware Valley, 1988–1990

This population-based study aimed to determine the incidence of native, prosthetic, and bioprosthetic valve nosocomial infective endocarditis (IE), and IE associated with the use of injected drugs. Patients with IE during 27 months over the years 1988 to 1990, and residing in any of 6 counties in the Philadelphia metropolitan area were identified. An expert panel reviewed all patients to verify the diagnosis. Incidence rates were estimated after adjustment for failure to recruit and underreporting. Of 853 potential patients, 670 (79%) met the inclusion criteria. The overall incidence rate of IE was 11.6 cases/100,000 person-years (95% confidence interval [CI] 10.8 to 12.4). The rates for specific types of IE were: 4.45 (95% CI 3.97 to 4.94) for community-acquired native valve, 0.94 (95% CI 0.72 to 1.12) for prosthetic valve, 0.94 (95% CI 0.71 to 1.16) for nosocomial, and 5.34 (95% CI 4.80 to 5.87) for IE associated with use of injected drugs. Previous population studies found overall incidence rates of 1.7 to 4 cases/100,000 person-years, similar to our rate for community-acquired native valve IE. Type-specific rates have not been previously reported. The higher overall rate in this study is partly related to the nigh prevalence of injection drug use in our area.

Perceptions of Job Discrimination Among Lower-Income, Elderly Part-Timers

Findings from a study of 164 part-time employed older adults (mean age = 67.1 years) placed by four senior employ- ment programs in the greater Philadelphia metropolitan area docu- ment an important aspect of the quality of the work experience of lower-income, white and minority (Hispanic and African American) elders. Analysis of quantitative index data suggest that discrimina- tion was not perceived to be a major impediment in the work lives of these individuals. Age discrimination, and to a lesser degree, racial and gender discrimination are experienced, but only by a small ro- portion of older workers in part-time jobs. When it does s&e. older workers verceive it to be reflected in reduced salaries, fewer promotions, arid inadequacies in fringe benefit packages. Given a series of qualitative responses offered by study subjects, the possibil- ity that i~tances of dikrimination, especially ageism, may 6e down- played by some elder part-time employees because of fear of job loss is not ruled out.

Short-run and long-run policies for increasing bicycle transportation for daily commuter trips

Long-run and short-run policies to increase the share of bicycle transportation for commuting to and from work are discussed. Analyses of data collected in the Philadelphia metropolitan area show that two general approaches can be taken to promote bicycle transportation. One is a set of policies geared to making bicycling safer and more convenient, essentially short-run ‘pro-bike’ policies. The other set is aimed at reducing the convenience of automobile commuting. This is an ‘anti-auto’ policy which can only be implemented in the long run. Since much of the sample had no choice but to commute by automobile, the impact of this constraint on the policy options is examined. In the long run it is assumed that commuters will have the choice of at least two modes by adjusting the distance between home and work locations. Specific proposals are discussed to implement some of the policies considered.

Breast silicone implants and risk of systemic lupus erythematosus

The uncertain safety of breast implants has been a major controversy of late, both in the lay press and in the scientific literature. A case-control study had been performed in the Philadelphia metropolitan area during 1985–1987 to investigate potential risk factors for systemic lupus erythematosus (SLE). A total of 219 eligible cases who met the American Rheumatism Association criteria for SLE were identified from the medical practices of cooperating rheumatologists in the area; 195 (89%) of these were enrolled in the study. Friends of the cases, matched to the cases on sex and age (±5 years) served as controls. For the current investigation, conducted during June 1992 through September 1992, we attempted to re-contact each of these individuals. Using a short telephone interview, we asked each subject to provide information on any surgery that they may have had prior to the index date, i.e. the year of diagnosis of SLE in the cases and the same year for the age-matched friend controls. Specific questions were asked about plastic surgery in general and breast implants in particular. 148 (75.9%) of the 195 SLE cases being sought and 111 (77.6%) of the 143 controls being sought agreed to be re-interviewed for this study. Only 1 (0.8%) out of 133 female SLE cases reported having had a breast implant, 8 years prior to the diagnosis of SLE. This compared to 0 out of the 100 female friend controls (Fisher exact one-tailed p-value = 0.57). If we use the results from the population-based controls of the Cancer and Steroid Hormone study, to reflect the frequency of surgical implants or injections to increase breast size (specifically, 8 out of 4754 controls), then the experience from our cases would provide an odds ratio (90% exact confidence interval) of 4.5 (0.2–27.3) (Fisher exact one-tailed p-value = 0.22). In conclusion, based on this very large case-control study of SLE, no association was seen between silicone breast implants and the subsequent development of SLE. While the power of the study was limited, it was sufficient to provide evidence against a very large association. Given this, and the other data available in the literature, it would seem that future studies of the association between silicone breast implants and connective tissue diseases should focus primarily on scleroderma.

Local Taxes, Public Services, and the Intrametropolitan Location of Firms and Households

This work examines the effects of local public sector tax and spending decisions on the intrametropolitan location of jobs and workers. Municipality-level data for the entire Philadelphia metropolitan area are used to estimate a two equation partial adjustment model of firm and household location. Effective local property and income tax rates and spending data for three (exhaustive) service categories are included. The model is estimated for total employment and six sectors The findings imply that employment location is more sensitive to local government activities than is household location. Firms m most sectors react to both tax and spending policies. The effects on employment of local tax increases can be partially offset if the higher taxes supplement particular types of spending. However, differences across sectors imply that the net effect on total employment will be negative except in very special circumstances. Household behavior, on the other hand, is affected only by school spending. The findings also imply that models based on highly aggregated measures of employment or economic activity understate the speed of adjustment of the system, resulting in overstated estimates of long-run tax and spending effects.

Critical care clinical nurse specialist in home health care: survey results.

Two surveys were designed and sent to health care providers in the Philadelphia metropolitan area. The purpose of the surveys was to explore whether there was a need for critical care CNSs (CCCNS) in the field of high-tech, complex home care and to determine the characteristics of that role. In addition, the surveys sought to identify the necessary curriculum content a CCCNS graduate program should include to prepare individuals for practice in home care. One survey was sent to home care providers and an amended version to in-hospital personnel identified as responsible for discharge planning. Eighty-three percent of the home care survey respondents and 85% of the in-hospital survey respondents perceived a need for a CCCNS in the high-tech, complex home care field. The identified roles of the CCCNS in home care were similar for both respondent groups. They included consultant to the home care agency, patient-family educator, staff educator, and hospital-to-home coordinator. Some suggestions for curriculum content included courses on technology, discharge planning, health policy, and chronic illness. Although a preliminary exploration, the surveys demonstrated the existence of patients with high-tech, complex home care needs and supported the belief that CCCNSs have a role in their care.