Baltimore-Washington Corridor Research Articles

Shared Communities: A Multinational Qualitative Study of Immigrant and Receiving Community Members.

Community psychology is central to understanding how immigrants and more established residents of their new settings join together to develop a shared sense of community and membership. In our present study, we explored how newer (i.e., first- and second-generation immigrants) and more established community members form multiple positive psychological sense of community (PSOC) with one another. We conducted a multinational, qualitative study of PSOC through interviews with 201 first- and second-generation immigrants and third generation or more "receiving community members" in three contexts (Baltimore-Washington corridor of the U.S.; Torino, Italy; Lecce, Italy). Results indicated numerous similarities among the ways in which participants constructed PSOC in shared and nonshared communities, regardless of immigration/citizenship status, length of community residence, city, country, age, or gender. Small, proximal, and salient communities were often particularly important to building positive PSOC, which was formed around diverse membership boundaries. As intersectional beings, members converged and diverged on many characteristics, providing multiple opportunities for members to bring diversity to their communities while sharing other characteristics deemed essential to membership. Nonetheless, findings point to significant, structural challenges rooted in power and privilege that must be confronted to bridge the community-diversity dialectic and build strong, shared sense of community.

Aerosol Indirect Effect and Cloud-base Height Observations in the North East of the United States

Aerosol impacts on cloud-base height were investigated based on the 5 years (2006 to 2010) groundbased observations of aerosol and cloud properties provided by an atmospheric measurement field station in the Baltimore-Washington corridor operated by Howard University. Opposite to the decreasing trend of the aerosol loading, an increasing trend of cloud-base height was found over the five years. During the investigation, the five-year summer time low-base clouds are separated into clean and polluted groups based on the aerosol particulate matter with aerodynamic diameter ≤ 2.5m (PM2.5) value. With the same lifting condensation level (LCL) the cloud-base heights were found lower under the polluted conditions than that under the clean conditions. Moreover, a significant negative relationship between the difference of cloud-base height to LCL and PM2.5 concentration was found based on the five years observations. This study showed that clouds might form at lower altitude under the polluted conditions compared to the clean conditions.

Multi-year ground-based observations of aerosol-cloud interactions in the Mid-Atlantic of the United States

The U.S. Mid-Atlantic region experiences a wide variability of aerosol loading and frequent episodes of elevated anthropogenic aerosol loading associated with urban pollution conditions during summer months. In this study, multi-year ground-based observations (2006 to 2010) of aerosol and cloud properties from passive, active and in situ measurements at an atmospheric measurement field station in the Baltimore–Washington corridor operated by Howard University were analyzed to examine aerosol indirect effect on single-layer warm clouds including cloud optical depth (COD), liquid water path (LWP), cloud droplet effective radius (Re) and cloud droplet number concentration (Nd) in this region. A greater occurrence of polluted episodes and cloud cases with smaller Re (<7µm) were found during the polluted year summers (2006, 2007 and 2008) than the clean year summers (2009 and 2010). The measurements of aerosol particulate matter with aerodynamic diameter≤2.5µm (PM2.5) were used to represent the aerosol loading under cloudy conditions. Significant negative relationships between cloud droplet Re and PM2.5 were observed. Cloud cases were separated into clean and polluted groups based on the value of PM2.5. The cloud droplet Re was found proportional to LWP under clean conditions but weakly dependent on LWP under polluted conditions. The Nd was proportional to LWP under polluted condition but weakly dependent on LWP under clean conditions. Moreover, the effects of increasing fine aerosol particles on modifying cloud microphysical properties were found more significant under large LWP than small LWP in this region.

Regional characteristics of the relationship between columnar AOD and surface PM2.5: Application of lidar aerosol extinction profiles over Baltimore–Washington Corridor during DISCOVER-AQ

The first field campaign of DISCOVER-AQ (Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality) took place in July 2011 over Baltimore–Washington Corridor (BWC). A suite of airborne remote sensing and in-situ sensors was deployed along with ground networks for mapping vertical and horizontal distribution of aerosols. Previous researches were based on a single lidar station because of the lack of regional coverage. This study uses the unique airborne HSRL (High Spectral Resolution Lidar) data to baseline PM2.5 (particulate matter of aerodynamic diameter less than 2.5 μm) estimates and applies to regional air quality with satellite AOD (Aerosol Optical Depth) retrievals over BWC (∼6500 km2). The linear approximation takes into account aerosols aloft above AML (Aerosol Mixing Layer) by normalizing AOD with haze layer height (i.e., AOD/HLH). The estimated PM2.5 mass concentrations by HSRL AOD/HLH are shown within 2 RMSE (Root Mean Square Error ∼9.6 μg/m3) with correlation ∼0.88 with the observed over BWC. Similar statistics are shown when applying HLH data from a single location over the distance of 100 km. In other words, a single lidar is feasible to cover the range of 100 km with expected uncertainties. The employment of MPLNET–AERONET (MicroPulse Lidar NETwork – AErosol RObotic NETwork) measurements at NASA GSFC produces similar statistics of PM2.5 estimates as those derived by HSRL. The synergy of active and passive remote sensing aerosol measurements provides the foundation for satellite application of air quality on a daily basis. For the optimal range of 10 km, the MODIS-estimated PM2.5 values are found satisfactory at 27 (out of 36) sunphotometer locations with mean RMSE of 1.6–3.3 μg/m3 relative to PM2.5 estimated by sunphotometers. The remaining 6 of 8 marginal sites are found in the coastal zone, for which associated large RMSE values ∼4.5–7.8 μg/m3 are most likely due to overestimated AOD because of water-contaminated pixels.

Linking Spatial Pattern and Biophysical Parameters of Urban Vegetation by Multitemporal Landsat Imagery

Rapid urbanization has profoundly transformed the urban vegetation structure and its biophysical condition throughout the world. This research examined the spatial pattern and temporal dynamic of different vegetation types in relation to two biophysical parameters of urban vegetation, the leaf area index and fraction of photosynthetically active radiation, through remote sensing techniques in the Baltimore-Washington corridor area from 1990 to 2010. The results show that the productivity of urban vegetation was affected by the urbanization and the associated fragmentation processes. These results help us track the vegetation changes caused by urbanization and anthropogenic land surface change.

Assessing spatiotemporal variations of greenness in the Baltimore–Washington corridor area

This paper aims to characterize and analyze the urban greenness change in the Baltimore–Washington corridor area. The general objectives for this study are: (1) to identify and analyze the urban greenness pattern and its changes, (2) to interpret and associate the change in urban greenness structure within its zoning area, (3) to characterize and discuss the influence of urbanization on the spatial distribution and temporal dynamic of urban green spaces. The linear spectral mixture analysis (LSMA) was adopted to extract the fraction maps of four endmembers (imperviousness, grassland, woodland, and soil) using Landsat Thematic Mapper (TM). The research results indicate that LSMA offers a better classified map than the traditional Maximum Likelihood Classification with an improved overall accuracy from 78.99% to 86.20%. The greenness dynamics within each census tract as well as planning zone were derived based on the each two successive fraction maps and fuzzy set concepts. The significant decrease of grassland in the business-based landscape (average green density decreased from 30% to 17%) with a slight decrease of woodland (from 63% to 60%) indicate the urbanization in the Baltimore–Washington corridor area impact its spatial morphology, structure, and ecological environment under the special socioeconomic development and reserve policies. The combination of remote sensing data and GIS zoning data provides us a comprehensive track on the pattern and process of urban greenness to deliver significant information for city planners and policy makers, as well as the unique dataset for other researcher to further evaluate the socioeconomic function of urban greenness.

Estimating the impact of urbanization on LAI and fPAR in the Baltimore–Washington corridor area

During the past 20 years the Baltimore–Washington corridor area has exhibited many classic characteristics of urbanization, including the loss of natural resources, landscape fragmentation, and declines in water quality. In this research, we estimated the impact of urbanization on leaf area index (LAI) and the fraction of photosynthetically active radiation (fPAR) absorbed by vegetation in the Baltimore–Washington corridor area. Multitemporal LAI and fPAR images were acquired using Landsat thematic mapper (TM) images from 1986 to 2004. The impact of urbanization on the vegetation productivity was further analyzed based on the changes of LAI and fPAR in different zoning areas between 1986 and 2004. The overlaid results of zoning, census data, and LAI and fPAR images proved that the productivity of urban greenness was greatly impacted by the urbanization when more human activities were involved. The image-based LAI and fPAR coupled with GIS zoning and census data proved their unique values in assessing the impact of urbanization on urban greenness.

Dynamic micro-assignment modeling approach for integrated multimodal urban corridor management

Development and analysis of demand management strategies for integrated multimodal urban corridor management requires application of a new generation of demand modeling and network analysis tools. This paper describes the development of a dynamic trip micro-assignment and (meso) simulation system that incorporates individual tripmaker choices of travel mode, departure time and route in multimodal urban transportation networks (with different travel modes such as drive alone, shared ride, bus rapid transit and metro rail). These travel choice dimensions are integrated in a stochastic utility maximization framework that considers multiple user decision criteria such as travel time, travel cost, schedule delay, as well as travel time reliability. A variational inequality model is first proposed to describe the general stochastic dynamic traffic user equilibrium problem. For a typical case that assumes the logit-based alternative choice model, this paper develops an equivalent gap function-based optimization formulation and a heuristic iterative solution procedure. Based on a multi-dimensional network representation, an efficient time-dependent least cost path algorithm is embedded to generate an intermodal route choice set that recognizes time-dependent mode transfer costs and feasible mode transfer sequences. A two-stage estimation procedure that can systematically utilize historical static demand information, time-dependent link counts, as well as empirically calibrated stochastic departure time choice models is proposed to infer commuters’ preferred arrival time distribution, which is important in modeling departure time choice dynamics. A case study based on a large-scale multimodal transportation network (adapted from the Baltimore–Washington corridor) is presented to illustrate the capabilities of the methodology and provide insight into the potential benefit of integrated multimodal corridor management.

An Exploration of Recent Club Drug Use among Rave Attendees

Raves are characterized by large numbers of youth dancing for long periods of time and by the use of "club drugs," such as 3, 4-methylenedioxymethamphetamine (MDMA or "ecstasy"). While a small body of research has explored the use of ecstasy and other club drugs (EOCD) among club rave attendees in the United States, we are aware of no studies that have investigated the relationship between EOCD use and high-risk sexual behaviors among members of this population. We explored the association between EOCD use and high-risk sexual behaviors among a sample of 283 club rave attendees interviewed during the spring and summer of 2005. Data were collected at 13 rave events in two different clubs along the Baltimore-Washington corridor between March 17 and September 3, 2005. Potential respondents were conveniently sampled and approached between 12 a.m. and 5 a.m. as they exited the clubs. Only 12% reported using ecstasy within the two days preceding the interview, findings considerably lower than our earlier studies of club rave attendees. Moreover, no significant relationship was discerned between recent MDMA use and high-risk sexual behavior. These findings suggest that the use of EOCD among rave attendees has diminished and that the allocation of significant resources to combat their proliferation, among this and other populations at risk for EOCD use, may be premature.

Exploring the Validity of Self-Reported Ecstasy Use Among Club Rave Attendees

While several empirical studies have focused on Ecstasy use among rave attendees, only one study has explored the validity of self-reported Ecstasy use within this population. To address this limitation, the authors collected self-report drug use information and oral fluid (OF) specimens from 96 club rave attendees within the Baltimore-Washington corridor between August and October 2000. The Kappa statistic is 0.59, suggesting a moderate relationship between the self-report and OF measures. Such accurate reporting bodes well for researchers interested in eliciting sensitive information from this population.

Identifying the Perceived and Diagnosed Prevalence of Ecstasy Dependence Among Club Rave Attendees

ABSTRACTThe “rave” phenomenon has been a major element in the resurgence of psychedelic drug use in Western society. Purportedly central to raves is the use of “club drugs,” such as 3,4-methylenedioxymethamphetamine (MDMA or “ecstasy”). To date, however, no studies have attempted to estimate MDMA dependence among rave attendees. In the current study, personal drug data were collected from 154 adult “club rave” attendees along the Baltimore-Washington corridor between September and November 2002. The Center for Substance Abuse Research (CESAR) Arrestee Drug Screener (CADS) was used to screen for ecstasy dependence. Seventeen percent of the sample was diagnosed with probable MDMA-dcpendencc. MDMA-dependent rave attendees were significantly more likely than non-dependents to be male, white, and to have used most illicit drugs during the 12 months preceding the interview. Logistic regression identified that gender, race, and past-year use of marijuana and PCP were the strongest predictors of MDMA dependence. Implications for these findings are discussed. /Article copies available for a fee from The Haworth Document Delivery Service: 1- 800-HA WORTH. E-mail address: <docdelivery@haworthpress.com> Website: <http://www.HaworthPress.com> © 2004 by The Haworth Press. Inc. All rights reserved.]

Estimating the Prevalence of Ecstasy use among Club Rave Attendees

The “rave” phenomenon has been a major element in the resurgence of psychedelic drug use in Western society. Purportedly central to raves is the use of “club drugs” such as 3,4-methylenedioxymethamphetamine (MDMA or “Ecstasy”). To date, however, few studies have examined the prevalence of Ecstasy use and dependence symptoms among rave attendees in the United States. In the current study, self-report drug use information and oral fluid (OF) specimens were collected from a sample of adult “club rave” attendees along the Baltimore-Washington corridor between September and November 2002. Data collection was scheduled between 12 midnight and 5 a.m. Participation rates were high. Of the 192 rave attendees approached, 80% completed the interview. Of those who completed the interview, 82% provided an OF specimen. Twenty-four percent of the respondents with usable specimens (N=103) reported using Ecstasy within the two days preceding the interview, while 30% tested positive for MDMA by OF analysis. Sixteen percent responded affirmatively to at least one of the three dependence symptoms. Self-reported 12-month Ecstasy users were more likely than non-users to be white, and recent users were more likely to have used most other drugs of abuse during the 12 months preceding the interview.

Analysis of a Summertime PM2.5 and Haze Episode in the Mid-Atlantic Region

Observations of the mass and chemical composition of particles less than 2.5 μm in aerodynamic diameter (PM2.5), light extinction, and meteorology in the urban Baltimore-Washington corridor during July 1999 and July 2000 are presented and analyzed to study summertime haze formation in the mid-Atlantic region. The mass fraction of ammoniated sulfate (SO4 2-) and carbonaceous material in PM2.5 were each ∼50% for cleaner air (PM2.5 < 10 μg/m3) but changed to ∼60% and ∼20%, respectively, for more polluted air (PM2.5 > 30 μg/m3). This signifies the role of SO4 2- in haze formation. Comparisons of data from this study with the Interagency Monitoring of Protected Visual Environments network suggest that SO4 2− is more regional than carbonaceous material and originates in part from upwind source regions. The light extinction coefficient is well correlated to PM2.5 mass plus water associated with inorganic salt, leading to a mass extinction efficiency of 7.6 ± 1.7 m2/g for hydrated aerosol. The most serious haze episode occurring between July 15 and 19, 1999, was characterized by westerly transport and recirculation slowing removal of pollutants. At the peak of this episode, 1-hr PM2.5 concentration reached ∼45 μg/m3, visual range dropped to ∼5 km, and aerosol water likely contributed to ∼40% of the light extinction coefficient.

An examination of the relationship between certain meteorological parameters and surface ozone variations in the Baltimore–Washington corridor

Fifteen years of ozone data from the United States Environmental Protection Agency's (EPA) Aerometric Information Retrieval System (AIRS) and surface and upper air meteorological data from National Weather Service (NWS) stations were used to determine the meteorological conditions in the Baltimore–Washington corridor area that are important in characterizing ozone variations. Three data sets were used in this study: the initial 15-year data set; a subset of the complete 15-year data set that was a 15-year summer data set; and another subset of the complete 15-year data set that only included those days when the daily maximum ozone concentration (DMOC) was greater than or equal to 100 ppb (DMOC⩾100 ppb). The results from this study indicated that the meteorological terms that affect ozone in the Baltimore–Washington corridor were compartmentalized; that is, the results were dependent on which data set was used in the study. When the entire 15-year data set was considered, the meteorological parameters that influenced ozone variations were temperature and dewpoint. The principal meteorological term, when only the 15-year short-term variations (i.e., variations with periods less than 30 days) of ozone were considered, was sky cover. When the 15-year summer data set was considered, the principal meteorological terms involved in the variation of ozone were temperature and sky cover; and when the data set in which the limitation DMOC⩾100 ppb was used, the principal meteorological terms were surface wind speed and sky cover. The results from this study indicated that high temperatures and large concentrations of water vapor are a necessary, but not a sufficient, condition for high ozone to be found in the Baltimore–Washington corridor. The sufficiency condition is satisfied when significant amounts of solar radiation reach and when stagnation conditions prevail in the surface layer at the same time.

Origins of fine aerosol mass in the Baltimore–Washington corridor: implications from observation, factor analysis, and ensemble air parcel back trajectories

Chemically speciated fine particulate matter (PM 2.5) and trace gases (including NH 3, HNO 3, CO, SO 2, NO y ) have been sampled at Fort Meade (FME: 39.10°N, 76.74°W; elevation 46 m MSL), Maryland, since July 1999. FME is suburban, located in the middle of the Baltimore–Washington corridor, and generally downwind of the highly industrialized Midwest. The PM 2.5 at FME is expected to be of both local and regional sources. Measurements over a 2-year period include eight seasonally representative months. The PM 2.5 shows an annual mean of 13 μg m −3 and primarily consists of sulfate, nitrate, ammonium, and carbonaceous material. Day-to-day and seasonal variations in the PM 2.5 chemical composition reflect changes of contribution from various sources. UNMIX, an innovative receptor model, is used to retrieve potential sources of the PM 2.5. A six-factor model, including regional sulfate, local sulfate, wood smoke, copper/iron processing industry, mobile, and secondary nitrate, is constructed and compared with reported source emission profiles. The six factors are studied further using an ensemble back trajectory method to identify possible source locations. Sources of local sulfate, mobile, and secondary nitrate are more localized around the receptor than those of other factors. Regional sulfate and wood smoke are more regional and associated with westerly and southerly transport, respectively. This study suggests that the local contribution to PM 2.5 mass can vary from <30% in summer to >60% in winter.

Gender, sexuality, and health in a turn-of-the-century "black metropolis".

or nearly a decade now, the Cultural Systems Analysis Group (CuSAG) has been engaged in critically important applied research in several fieldwork sites in the Baltimore-Washington metropolitan area. CuSAG's qualitative and quantitative research has focused on low-income African Americans, the quality of everyday life in their communities, and the uneven structure of opportunity available for meeting both individual and community-wide needs in such domains as employment and economic development, education, housing, health care, and governance. In partnership with a number of local and national organizations devoted to public policy matters, CuSAG has used an impressively diverse methodological repertoire to triangulate qualitative and quantitative methods to address a range of difficult and important questions concerning the complex and contradictory predicament of the population problematically characterized as an underclass (Maxwell 1993). Under Tony L. Whitehead's able direction, the critical anthropological project that CuSAG pursues is holistic and relatively systematic in its scope of data collection and analysis. Whitehead resists nihilistic views of the social world and of the ability of social scientists to analyze, explain, and help to change reality. In this respect as well as in others, the larger CuSAG project draws on a century-long tradition of urban research, particularly the trajectory that W.E.B. DuBois (1899) initiated with The Philadelphia Negro. A bit closer to our anthropological home, St. Clair Drake and Horace Cayton's classic Black Metropolis (1945) brought the concerns of DuBoisian activist scholarship into the peripheral vision of the anthropological canon, from which it was virtually excluded (Harrison 1988, 1992). Drake and Cayton's classic ethnographic and historical sociological study of Chicago's South Side was the first research to involve anthropology in the study of a large metropolitan center (Harrison 1988, 1992). Fifty years before its time, the Black Metropolis project foreshadowed many of the trends that have become central to sociocultural anthropology today. Whitehead's research in the impoverished black metropolis of the Baltimore-Washington corridor, like the best work within this activist-oriented tradition of African American social research, interrogates local

Atmospheric changes in a growing community (the Columbia, Maryland experience)

An account of seven years of meteorological observations in the growing town of Columbia, Howard County, Maryland, in the Baltimore-Washington corridor is given. Information was collected from fixed stations and mobile surveys. In the interval from 1968 to 1975 the town grew from 200 to 20000 inhabitants, with building activity eliminating the original diversified rural microclimates. An unmistakable urban heat island has developed that is quite notable nocturnally when it maximally reaches 8° C in the densely built-up town center. The time series of the maximal heat island is linearly related to the logarithm of population figure. At midday on sunny days the IR surface temperatures are directly proportional to the per cent of area built-up. The radiation balance reflects the changes in the urbanized area. There is little heat loss from evapotranspiration but large heat transport into the surface (day) and out of the surface (night). No effect on precipitation is (as yet) discernible. Relative humidities are lower in the town area than in the rural district. Roughness has increased and wind speeds have been reduced. In all seasons, except summer, hours of turbulent wind have decreased. Run-off has become typically urban and air pollution has increased (presumably from motor vehicle traffic). All findings support earlier studies on town climate and reveal considerable detail on the progress of atmospheric modification in the urbanization process.