Adapting to Extreme Events: Household Response to Floods in Urban Areas

This dissertation is an economic study of household-level decisions related to flood risk mitigation. It is composed of four chapters that focus on the 2011 Thailand flood, the world’s most costly flood event in the past 30 years. The first chapter examines the magnitude and composition of economic costs that households in Bangkok bore during the 2011 flood. Two rounds of surveys with 469 Bangkok households collected detailed information on a broad set of flood costs. Results indicate that total flood cost was substantial. The median cost was equivalent to half of annual household spending. However, structural damage to homes was surprisingly low, given the depth and duration of the flood. The second chapter assesses how online information can enable households to reduce flood losses. Propensity score matching is used to test for evidence of a relationship between social media use and flood loss. Results indicate that social media use enabled households to reduce mean losses by 37%. Social media offered information that was not available from other sources, such as localized and nearly real-time updates of flood location and depth. With knowledge of current flood conditions, households could move belongings to higher ground before floodwaters arrived. The third chapter shifts focus to longer-term mitigation actions. It presents results from a randomized experiment that tests the effect of information on household uptake of flood insurance and home retrofits. A sample of 364 flood-prone households in Bangkok was randomly split into treatment and control groups. The treatment group received practical details on home retrofits and subsidized flood insurance as well as social norm information regarding insurance purchase decisions of peers. Results indicate that the information intervention increased insurance purchases by about four percent, while no effect was detected for home retrofits. The fourth chapter evaluates the social benefits of the information intervention presented in the third chapter. Results suggest that the intervention raises welfare of households, but not society. Furthermore, greater benefits are associated with better informing households that have high insurance demand, compared to using social pressure to persuade those with low demand.Doctor of Philosoph

The Green Paradox of U.S. Biofuel Subsidies: Impact on Greenhouse Gas Emissions

This paper presents the first comprehensive estimates of the impact of U.S. biofuel subsidies on greenhouse gas emissions. Although U.S. support for biofuels is large and growing, the associated impact on greenhouse gas emissions remains unclear. The effect of biofuel subsidies on emissions is determined by the relative magnitudes of countervailing substitution and price effects. Regulators typically ignore the price effect of biofuel policies, and therefore do not fully account for market and climate impacts. We develop an economic simulation model of U.S. energy markets to estimate the impact of biofuel subsidies on greenhouse gas emissions from 2005 through 2009. The model represents end-use consumption of oil, natural gas, coal and electricity in four sectors. We find that the subsidies for ethanol increased greenhouse gas emissions, while those for biodiesel have an ambiguous effect. Thus, ethanol subsidies create a green paradox. Although ethanol has lower lifecycle greenhouse gas emissions than gasoline, the subsidies lower the market price of blended fuel, which increases overall fuel consumption and increase total greenhouse gas emissions. These findings question the suitability of using ethanol subsidies to achieve climate goals and highlight the importance of accounting for the price effect of biofuel policies

Health-Based Violations of the Safe Drinking Water Act, 1982-2015

Regression dataset for analysis reported in: Allaire, M., Wu, H., Lall, U. (2018). National Trends in Drinking Water Quality Violations. Proceedings of the National Academy of Sciences

Bottled Water Sales and Water Quality Violations, 2006-2015

Regression dataset for analysis reported in: Allaire, M., Mackay, T., Zheng, S., Lall, U. (2019). Community Response to Impaired Water: Understanding Averting Behavior with Bottled Water Sales. Proceedings of the National Academy of Sciences

Disparities in drinking water quality: evidence from California

Reducing disparities in drinking water quality is a state-level priority in California, yet targeting communities for assistance is hindered by the lack of empirical evidence regarding populations disproportionately affected. The study addresses this gap by analyzing drinking water quality violations and identifying the types of communities disproportionately burdened by water contaminants. Using a sample of 1,710 Community Water Systems (CWSs) and probit regression models, we analyzed the likelihood of violation as a function of low-income, minority groups, and vulnerable populations. Results indicate that environmental justice concerns are prevalent. Low-income communities and minority groups (Hispanics and non-Whites) face greater likelihood of water quality violations. Low-income communities are 1.77% more likely to have any health-related violations. Severely disadvantaged communities face greater likelihood (3.44%) of water quality violations. Tribal water systems are 2% more likely to violate the Total Coliform Rule. Children aged five and under are 3% more likely to be exposed to health-based water quality violations. Failure to address prior violations leads to greater likelihood (38.94%) of future violations, while large utility systems and purchased water sources have the propensity to reduce violations. Overall, these findings can guide policy decisions to prioritize assistance to communities disproportionately impacted by poor water quality. HIGHLIGHTS About 0.3–3.0 million populations are served by noncompliant CWSs each year.; Failure to address previous water contaminant violations has a high marginal effect.; Tribal water systems made up 3.9% of CWS observations but incurred 10.7% of violations.; Small CWSs are particularly burdened by shifting regulations due to capacity constraints.; Latinos and African Americans are associated with nitrate and arsenic violations, respectively.

National trends in drinking water quality violations

Ensuring safe water supply for communities across the United States is a growing challenge in the face of aging infrastructure, impaired source water, and strained community finances. In the aftermath of the Flint lead crisis, there is an urgent need to assess the current state of US drinking water. However, no nationwide assessment has yet been conducted on trends in drinking water quality violations across several decades. Efforts to reduce violations are of national concern given that, in 2015, nearly 21 million people relied on community water systems that violated health-based quality standards. In this paper, we evaluate spatial and temporal patterns in health-related violations of the Safe Drinking Water Act using a panel dataset of 17,900 community water systems over the period 1982-2015. We also identify vulnerability factors of communities and water systems through probit regression. Increasing time trends and violation hot spots are detected in several states, particularly in the Southwest region. Repeat violations are prevalent in locations of violation hot spots, indicating that water systems in these regions struggle with recurring issues. In terms of vulnerability factors, we find that violation incidence in rural areas is substantially higher than in urbanized areas. Meanwhile, private ownership and purchased water source are associated with compliance. These findings indicate the types of underperforming systems that might benefit from assistance in achieving consistent compliance. We discuss why certain violations might be clustered in some regions and strategies for improving national drinking water quality

Assessing the Risk of Legionella Infection through Showering with Untreated Rain Cistern Water in a Tropical Environment

In September 2017, two category-5 hurricanes Irma and Maria swept through the Caribbean Sea in what is now known as the region’s most active hurricane season on record, leaving disastrous effects on infrastructure and people’s lives. In the U.S. Virgin Islands, rain cisterns are commonly used for harvesting roof-top rainwater for household water needs. High prevalence of Legionella spp. was found in the cistern water after the hurricanes. This study carried out a quantitative microbial risk assessment to estimate the health risks associated with Legionella through inhalation of aerosols from showering using water from cisterns after the hurricanes. Legionella concentrations were modeled based on the Legionella detected in post-hurricane water samples and reported total viable heterotrophic bacterial counts in cistern water. The inhalation dose was modeled using a Monte Carlo simulation of shower water aerosol concentrations according to shower water temperature, shower duration, inhalation rates, and shower flow rates. The risk of infection was calculated based on a previously established dose–response model from Legionella infection of guinea pigs. The results indicated median daily risk of 2.5 × 10−6 to 2.5 × 10−4 depending on shower temperature, and median annual risk of 9.1 × 10−4 to 1.4 × 10−2. Results were discussed and compared with household survey results for a better understanding of local perceived risk versus objective risk surrounding local water supplies

Detecting community response to water quality violations using bottled water sales

Drinking-water contaminants pose a risk to public health. When confronted with elevated levels of contaminants, individuals can take actions to reduce exposure. Yet, few studies address averting behavior due to impaired water, particularly in high-income countries. This is a problem of national interest, given that 9 million to 45 million people have been affected by water quality violations in each of the past 34 years. No national analysis has focused on the extent to which communities reduce exposure to contaminated drinking water. Here, we present an assessment that sheds light on how communities across the United States respond to violations of the Safe Drinking Water Act, using consumer purchases of bottled water. This study provides insight into how averting behavior differs across violation types and community demographics. We estimate the change in sales due to water quality violations, using a panel dataset of weekly sales and violation records in 2,151 counties from 2006 to 2015. Critical findings show that violations which pose an immediate health risk are associated with a 14% increase in bottled water sales. Generally, greater averting action is taken against contaminants that might pose a greater perceived health risk and that require more immediate public notification. Rural, low-income communities do not take significant averting action for elevated levels of nitrate, yet experience a higher prevalence of nitrate violations. Findings can inform improvements in public notification and targeting of technical assistance from state regulators and public health agencies in order to reduce community exposure to contaminants

Forecasts of mortality and economic losses from poor water and sanitation in sub-Saharan Africa

This paper presents country-level estimates of water, sanitation and hygiene (WASH)-related mortality and the economic losses associated with poor access to water and sanitation infrastructure in sub-Saharan Africa (SSA) from 1990 to 2050. We examine the extent to which the changes that accompany economic growth will "solve" water and sanitation problems in SSA and, if so, how long it will take. Our simulations suggest that WASH-related mortality will continue to differ markedly across countries in sub-Saharan Africa. In many countries, expected economic growth alone will not be sufficient to eliminate WASH-related mortality or eliminate the economic losses associated with poor access to water and sanitation infrastructure by 2050. In other countries, WASH-related mortality will sharply decline, although the economic losses associated with the time spent collecting water are forecast to persist. Overall, our findings suggest that in a subset of countries in sub-Saharan Africa (e.g., Angola, Niger, Sierra Leone, Chad and several others), WASH-related investments will remain a priority for decades and require a long-term, sustained effort from both the international community and national governments