published journal article

Examining the joint effects of heatwaves, air pollution, and green space on the risk of preterm birth in California

Environmental Research Letters

Publication Date

October 1, 2020

Author(s)

Lizhi Sun, Sindana D. Ilango, Lara Schwarz, Xuting Wang, Chia-Lin Chen, Jean M. Lawrence, Jun Wu, Tarik Benmarhnia

Abstract

Background. Exposure to high air temperature in late pregnancy is increasingly recognized as a risk factor for preterm birth (PTB). However, the combined effects of heatwaves with air pollution and green space are still unexplored. In the context of climate change, investigating the interaction between environmental factors and identifying communities at higher risk is important to better understand the etiological mechanisms and design targeted interventions towards certain women during pregnancy. Objectives. To examine the combined effects of heatwaves, air pollution and green space exposure on the risk of PTB. Methods. California birth certificate records for singleton births (2005–2013) were obtained. Residential zip code-specific daily temperature during the last week of gestation was used to create 12 definitions of heatwave with varying temperature thresholds and durations. We fit multi-level Cox proportional hazard models with time to PTB as the outcome and gestational week as the temporal unit. Relative risk due to interaction (RERI) was applied to estimate the additive interactive effect of air pollution and green space on the effect of heatwaves on PTB. Results. In total, 1 967 300 births were included in this study. For PM2.5, PM10 and O3, we found positive additive interactions (RERIs >0) between heatwaves and higher air pollution levels. Combined effects of heatwaves and green space indicated negative interactions (RERIs <0) for less intense heatwaves (i.e. shorter duration or relatively low temperature), whereas there were potential positive interactions (RERIs >0) for more intense heatwaves. Conclusion. This study found synergistic harmful effects for heatwaves with air pollution, and potential positive interactions with lack of green space on PTB. Implementing interventions, such as heat warning systems and behavioral changes, targeted toward pregnant women at risk for high air pollution and low green space exposures may optimize the benefits of reducing acute exposure to extreme heat before delivery.

Suggested Citation
Yi Sun, Sindana D. Ilango, Lara Schwarz, Qiong Wang, Jiu-Chiuan Chen, Jean M. Lawrence, Jun Wu and Tarik Benmarhnia (2020) “Examining the joint effects of heatwaves, air pollution, and green space on the risk of preterm birth in California”, Environmental Research Letters, 15(10), p. 104099. Available at: 10.1088/1748-9326/abb8a3.

published journal article

Improving community resilience to disrupted food access: Empirical spatio-temporal analysis of volunteer-based crowdsourced food delivery

Journal of Transport Geography

Publication Date

December 1, 2024

Author(s)

Gretchen Bella, Elisa Borowski, Amanda Stathopoulos

Abstract

Unplanned disaster events can greatly disrupt access to essential resources, with calamitous outcomes for already vulnerable households. This is particularly challenging when concurrent extreme events affect both the ability of households to travel and the functioning of traditional transportation networks that supply resources. This paper examines the use of volunteer-based crowdsourced food delivery as a community resilience tactic to improve food accessibility during overlapping disruptions with lasting effects, such as the COVID-19 pandemic and climate disasters. The study uses large-scale spatio-temporal data (n = 28,512) on crowdsourced food deliveries in Houston, TX, spanning from 2020 through 2022, merged with data on community demographics and significant disruptive events occurring in the two-year timespan. Three research lenses are applied to understand the effectiveness of crowdsourced food delivery programs for food access recovery: 1) geographic analysis illustrates hot spots of demand and impacts of disasters on requests for food assistance within the study area; 2) linear spatio-temporal modeling identifies a distinction between shelter-in-place emergencies and evacuation emergencies regarding demand for food assistance; 3) structural equation modeling identifies socially vulnerable identity clusters that impact requests for food assistance. The findings from the study suggest that volunteer-based crowdsourced food delivery adds to the resilience of food insecure communities, supporting its effectiveness in serving its intended populations. The paper contributes to the literature by illustrating how resilience is a function of time and space, and that similarly, there is value in a dynamic representation of community vulnerability. The results point to a new approach to resource recovery following disaster events by shifting the burden of transportation from resource-seekers and traditional transportation systems to home delivery by a crowdsourced volunteer network.

Suggested Citation
Gretchen Bella, Elisa Borowski and Amanda Stathopoulos (2024) “Improving community resilience to disrupted food access: Empirical spatio-temporal analysis of volunteer-based crowdsourced food delivery”, Journal of Transport Geography, 121, p. 104018. Available at: 10.1016/j.jtrangeo.2024.104018.

published journal article

Decision problem structuring: Generating options

IEEE Transactions on Systems, Man, and Cybernetics

Publication Date

January 1, 1988
Suggested Citation
L.R. Keller and J.L. Ho (1988) “Decision problem structuring: Generating options”, IEEE Transactions on Systems, Man, and Cybernetics, 18(5), pp. 715–728. Available at: 10.1109/21.21599.

conference paper

Heterogeneity in Activity-travel Patterns of Public Transit Users

100th Transportation Research Board (TRB) Annual Meeting

Publication Date

January 1, 2021
Suggested Citation
Rezwana Rafiq and Michael G McNally (2021) “Heterogeneity in Activity-travel Patterns of Public Transit Users”. 100th Transportation Research Board (TRB) Annual Meeting, Washington, DC.

published journal article

Risk assessment of soil heavy metal contamination at the census tract level in the city of Santa Ana, CA: implications for health and environmental justice

Environmental Science: Processes & Impacts

Publication Date

January 1, 2021

Author(s)

Shahir Masri, Alana M. W. LeBrón, Michael D. Logue, Enrique Valencia, Gabriela Ruiz, Deldi Reyes, Jun Wu

Abstract

Soil-based risk assessment shows a U.S. city to exceed federal acceptable risk levels for both non-carcinogenic and carcinogenic health outcomes in many areas, with total risk and soil contamination being correlated with socioeconomic factors. , (1) Background: exposure to heavy metals is associated with adverse health effects and disproportionately impacts low-income communities and communities of color. We carried out a community-based participatory research study to examine the distribution of heavy metal concentrations in the soil and social vulnerabilities to soil heavy metal exposures across Census tracts in Santa Ana, CA. (2) Methods: soil samples ( n = 1528) of eight heavy metals including lead (Pb), arsenic (As), manganese (Mn), chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd), and zinc (Zn) were collected in 2018 across Santa Ana, CA, at a high spatial resolution and analyzed using XRF analysis. Metal concentrations were mapped out and American Community Survey data was utilized to assess metals throughout Census tracts in terms of social and economic variables. Risk assessment was conducted to evaluate carcinogenic and non-carcinogenic risk. (3) Results: concentrations of soil metals varied according to landuse type and socioeconomic factors. Census tracts where the median household income was under $50 000 had 390%, 92.9%, 56.6%, and 54.3% higher Pb, Zn, Cd, and As concentrations compared to high-income counterparts. All Census tracts in Santa Ana showed hazard index >1, implying the potential for non-carcinogenic health effects, and nearly all Census tracts showed a cancer risk above 10 −4 , implying a greater than acceptable risk. Risk was predominantly driven by childhood exposure. (4) Conclusions: findings inform initiatives related to environmental justice and highlight subpopulations at elevated risk of heavy metal exposure, in turn underscoring the need for community-driven recommendations for policies and other actions to remediate soil contamination and protect the health of residents.

Suggested Citation
Shahir Masri, Alana M. W. LeBrón, Michael D. Logue, Enrique Valencia, Abel Ruiz, Abigail Reyes and Jun Wu (2021) “Risk assessment of soil heavy metal contamination at the census tract level in the city of Santa Ana, CA: implications for health and environmental justice”, Environmental Science: Processes & Impacts, 23(6), pp. 812–830. Available at: 10.1039/D1EM00007A.

policy brief

Electrified Buses Provide Life Cycle Environmental Benefits but Need Cost Reductions and Policy Support for Near-Term Adoption

Publication Date

November 1, 2019

Author(s)

Abstract

In December 2018, the California Air Resources Board (CARB) approved the Innovative Clean Transit regulation, which is designed to transition the state to all-electric bus fleets by 2040. To comply with this first-of its-kind regulation, transit agencies have two alternatives: battery electric buses (BEBs) and hydrogen fuel cell electric buses (FCEBs). These options vary in energy requirements, overall effectiveness in reducing different emission types, associated life cycle costs (including disposal of the bus), and ability to meet operating needs of transit agencies. To support transit agencies and decision makers transition to cleaner bus technologies, researchers at UC Irvine developed a life cycle-based analysis (LCA) tool to estimate the potential costs and benefits of switching to BEBs and FCEBs compared to conventional buses. The LCA tool was tested on the Orange County Transportation Authority (OCTA) to better understand the environmental impacts and cost constraints.

Suggested Citation
G. Scott Samuelsen (2019) Electrified Buses Provide Life Cycle Environmental Benefits but Need Cost Reductions and Policy Support for Near-Term Adoption. Policy Brief. Available at: https://escholarship.org/uc/item/504062dq (Accessed: October 11, 2023).

published journal article

A multi-commodity Lighthill–Whitham–Richards model of lane-changing traffic flow

Transportation Research Part B: Methodological

Publication Date

November 1, 2013

Author(s)

Suggested Citation
Wen-Long Jin (2013) “A multi-commodity Lighthill–Whitham–Richards model of lane-changing traffic flow”, Transportation Research Part B: Methodological, 57, pp. 361–377. Available at: 10.1016/j.trb.2013.06.002.

working paper

Transit Agency Use of Private Sector Strategies for Commuter Transportation

Publication Date

September 5, 1983

Author(s)

Abstract

Demand for public transit services in most urban areas is increasingly concentrated in the peak period. However, peak period service is significantly more expensive to the transit agency than its other services and usually produces larger deficits. Faced with pressures to maintain or increase commuter services, yet also to control rapidly escalating deficits, transit agencies are in need of strategies which improve the cost-effectiveness of commuter transportation. Several innovative service strategies which make use of the private sector–service contracting, service turnovers, vanpooling-chave considerable potential to achieve this objective, and are alternatives to traditional transit agency approaches to problem solving.Based on a study of 8 transit agencies in 8 diverse metropolitan areas, all with some significant private sector activity in commuter transportation, this paper examines transit agency utilization of these innovative private sector strategies. It determines the reasons these agencies have or have not adopted these strategies, and identifies the major barriers to their more widespread utilization. The initial incentive to consider non-traditional approaches comes from fiscal and/or service pressures which require some change in the status quo, but whether private sector strategies are actually utilized depends largely on four factors: 1) management interest in non-traditional approaches, 2) analyses which demonstrate the utility of innovative approaches, 3) discretionary rather than dedicated local subsidies, and 4) the ability of local government officials to influence the transit agency’s service and budget decisions. The main barriers to innovation are traditional management orientation, labor constraints posed by federal legislation and/or local union contracts, and subsidy and decision making arrangements which give the agency no strong incentive to improve the cost-effectiveness of its different types of services.

Suggested Citation
Roger F. Teal, Genevieve Giuliano and Mary E. Brenner (1983) Transit Agency Use of Private Sector Strategies for Commuter Transportation. Working Paper UCI-ITS-WP-83-1. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/79g6v1qv.

published journal article

An analytical model of multihop connectivity of inter-vehicle communication systems

IEEE Transactions on Wireless Communications

Publication Date

January 1, 2010
Suggested Citation
Wen-Long Jin and Wilfred Recker (2010) “An analytical model of multihop connectivity of inter-vehicle communication systems”, IEEE Transactions on Wireless Communications, 9(1), pp. 106–112. Available at: 10.1109/twc.2010.01.05545.

book/book chapter

The mediterranean sea

Publication Date

January 1, 2012

Author(s)

T. Scovazzi, Joseph Dimento, A.J. Hickman
Suggested Citation
T. Scovazzi, J.F. DiMento and A.J. Hickman (2012) “The mediterranean sea”, in Environmental governance of the great seas, pp. 85–128.