heat key terms

KEY TERMS Acute Risks: Immediate, severe threats posed by sudden or intense events, such as extreme heat waves, which can lead to rapid health emergencies, infrastructure failure, or ecological disruption. Albedo: A measure of how much light or radiation is reflected by a surface, with higher albedo surfaces reflecting more and absorbing less heat, making them important in controlling a building’s heat gain. Blue-Green Infrastructure: Infrastructure that combines elements of both blue (water-based) and green (plant-based) systems to manage water resources in a sustainable way while providing cooling benefits and enhancing urban resilience. This approach includes features like rain gardens, bioswales, permeable pavements, and green roofs that help manage stormwater, reduce urban heat, improve air quality, and increase biodiversity in urban settings. Chronic Risks: Ongoing threats that occur due to prolonged exposure to certain conditions, such as consistently high temperatures, leading to long-term health, environmental, and structural issues. Climate Change: Rising global temperatures due to increased greenhouse gas emissions intensify heat waves and lead to overall higher average temperatures than in the past. Community: A group of people living in the same area who share common interests and concerns. In the context of heat and health, it refers to residents of a neighborhood, city, or region who may be impacted by heat together. Cooling Centers: Public spaces like libraries, malls, or community centers designated to provide relief from extreme heat, especially for vulnerable populations. Cool Pavements: Pavement technologies that reflect more solar energy and absorb less heat, contributing to lower surface and ambient temperatures in urban environments. Environmental Justice: The fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. In the context of heat, it ensures all communities have the resources and support to cope with heat impacts. Extreme Heat: Significantly above-average temperatures that can occur during heat waves or as a result of an exacerbated urban heat island effect. Extreme heat can impact public health, energy resources, and ecosystems. Extreme Heat Event: A period of high heat and humidity with temperatures above 90°F for at least two to three days with both elevated daytime and nighttime temperatures. Heat: The form of energy transferred between systems or objects with different temperatures (flowing from the higher to lower temperature system). In weather terms, it often refers to the perceptible increase in air temperature felt by humans. Heat Action Plans: City- or community-level strategies designed to mitigate the impacts of extreme heat through preparedness, public education, and infrastructure improvements. Heat Domes: High-pressure systems that can trap heat in a localized area for extended periods of time. Heat Equity: Addressing disproportionate exposure to extreme heat among vulnerable populations, particularly in low-income housing or marginalized communities lacking access to cooling resources. Heat Exhaustion: A condition caused by prolonged exposure to high temperatures, often accompanied by dehydration. Symptoms include heavy sweating, weakness, dizziness, nausea, and a rapid pulse. It is a precursor to heat stroke and requires immediate cooling and hydration to prevent escalation. Heat Index: A measure that combines air temperature, wind speed, and relative humidity to determine an apparent temperature—how hot it feels. Also referred to as “feels like” temperature. Heat-Related Illnesses: Medical conditions, including burns and, in order of severity, heat cramps, heat exhaustion, and heat stroke caused by the body’s inability to regulate core temperature during extreme heat events or withstand contact with extremely hot surfaces. Heat Resilience: The capacity of individuals, communities, organizations, and natural systems to survive, adapt, and grow in the face of prolonged periods of intense heat. HUD - EXTREME HEAT PLAYBOOK 2024 INTRODUCTION 11 Heat Stress: The strain on human health caused by prolonged exposure to high temperatures, particularly in poorly ventilated or non-climate-controlled housing. Heat Stroke: A severe and potentially life-threatening condition resulting from prolonged exposure to extreme heat, causing the body’s temperature regulation system to fail. Symptoms include a body temperature above 104°F (40°C), confusion, unconsciousness, lack of sweating, and a rapid or strong pulse. Immediate medical attention is required to prevent serious complications or death. Heatwave: A prolonged period of excessively hot weather, often accompanied by high humidity, that lasts for several days or more; can lead to serious health risks, especially for vulnerable populations, and can exacerbate existing conditions like air pollution, drought, and energy demand. They are typically defined relative to the usual climate of a location and can vary in severity based on temperature thresholds. Humidity: The amount of moisture in the air, which can intensify the feeling of heat during a heatwave and increase the risk of heat-related illnesses. Mechanical Cooling: Indoor cooling using technology such as air conditioners, heat pumps, and evaporative coolers. Nature-Based Solutions: Actions that utilize nature to address social challenges. Examples include planting trees for shade, creating green roofs to cool buildings, or restoring wetlands to manage water flow, which can all help mitigate heat impacts. Passive Cooling: Techniques such as smart ventilation, shading devices, and cool roofs that reduce the overall cooling load on buildings and enhance energy efficiency by reducing the need for mechanical cooling. Public-Private Partnership: Generally, a long-term contract between a private party and a government entity, for providing a public asset or service, in which the private party bears significant risk and management responsibility, and remuneration is linked to performance. Reflective Materials: Materials that have high reflectivity, used on building exteriors, streets, and walkways to reduce heat absorption and lower surrounding air temperatures. Resilience Hub: Community-serving, locally managed facilities that provide tailored, essential services and shelter during emergencies and foster long-term resilience with coordinated communication, resource distribution, and carbon reduction while improving quality of life across five foundational areas: services and programs, communications, building and landscape, power, and facility operations. Also known as resilience centers. Temperature: A measure of the warmth or coldness of an object or environment, typically expressed in degrees (Celsius, Fahrenheit, etc.). In the context of weather, it is one of the primary metrics used to describe the state of the atmosphere at a given time and place. Thermal Comfort: The measurement of a person’s satisfaction with their thermal environment - how hot or cold they feel. An individual’s thermal comfort is influenced by weather and environmental factors as well as personal factors like metabolic rate, clothing worn, age, and more. Thermal Mass: The ability of a material to absorb, store, and release heat energy. High thermal mass materials can help regulate indoor temperatures by absorbing heat during the day and releasing it at night, thus reducing temperature fluctuations. Tree Canopy: The layer of leaves, branches, and stems of trees that provide coverage and shade over the ground. Urban Heat Island (UHI) - An urban area that is significantly warmer than its surrounding areas due to human activities, such as the extensive use of concrete and asphalt which absorb and retain heat, as well as limited vegetation. Vulnerable Populations: Groups of individuals with a greater risk of heat-related illness or death due to health factors (chronic illness, medication that limits sweating, disability), socioeconomic factors (living in an urban heat island, living alone, low-income), or greater exposure to heat (working outdoors or without air conditioning, experiencing homelessness, exercising strenuously). Weatherization: The process of sealing homes against heat entry through improved insulation, windows, and doors.