Glossary of Terms

Any substance in the air that can have harmful effects on human health, the environment, or both. Air pollutants can come from natural sources, such as wildfires, or from human activities, including industrial processes, transportation, and energy production. Common air pollutants include particulate matter, ozone, nitrogen oxides, sulfur dioxide, toxic air contaminants, and carbon monoxide.

Reports by members of the public about an air quality problem. Reports can be made online on the Air District’s website or by calling a 24-hour toll-free phone line. Air pollution complaint investigations are a crucial part of the daily work of Air District inspectors. The Air District investigates all air pollution complaints to determine facts and circumstances surrounding alleged air emission releases and takes appropriate enforcement and legal actions to address violations of any air quality regulation.

Bill passed into state law in 2017 that requires all major local air districts in the state to partner with communities to develop plans to reduce air pollution in their neighborhoods or to do community air monitoring. Communities selected by the state for partnership are those that have relatively higher levels of air pollution than average, along with health vulnerabilities, such as higher asthma rates, cardiovascular disease, and cancer risk. These are often the same communities that have been subjected to discriminatory federal, state, and local policies including redlining, urban renewal, highway construction and local zoning codes that allow polluting industries to locate in or alongside residential neighborhoods. These communities have experienced resulting disinvestment, limited access to health services and healthy food, low quality education, and few local parks and open spaces. They are most often low-income communities of color.

A California law that requires government agencies to consider the environmental consequences of their actions before they approve plans and policies, or prior to acting on a project. The law has multiple purposes. The purposes include: to inform government decision makers and the public about the potential environmental effects of proposed activities; to identify the ways that environmental damage can be avoided or significantly reduced; to prevent significant, avoidable environmental damage by requiring changes in projects, either by the adoption of alternatives or imposition of mitigation measures; and to disclose to the public why a project was approved if that project has significant environmental impacts that cannot be mitigated to a less than significant level. Overall, the law aims to promote informed decision-making, transparency, and environmental protection in California’s development and land use planning processes.

Any carbon dioxide released into the atmosphere from human activities is balanced by an equivalent amount being removed.

A federal law in the United States that prohibits discrimination based on race, color, or national origin in programs and activities receiving federal financial assistance. The law states: “No person in the United States shall, on the ground of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving Federal financial assistance.” The purpose of Title VI is to promote equal access and opportunities for all individuals, regardless of race, color, or national origin, and to address discrimination in federally funded programs and activities. 

Changes to the Earth’s climate that affect weather, oceans, ecosystems, and global temperatures. Human activities are driving climate change, primarily through the release of billions of tons of greenhouse gases each year. Greenhouse gases trap heat in the atmosphere, which increases global temperatures. Resulting climate impacts include more frequent and severe heatwaves, rain and snow, floods, droughts, and wildfires. Climate change also raises ocean temperatures, acidity, and sea level due to rapid melting of glaciers and sea ice.

Established in late 2021 to provide guidance to the Air District Board of Directors on programs and policies that impact all communities, including those overburdened by air pollution. The Community Advisory Council makes recommendations to the Air District on equity and environmental justice matters to improve air quality in all communities, prioritizing those most impacted by air pollution.

The United States Environmental Protection Agency defines cumulative impacts as “the total effects of chemical and non-chemical stressors on the health, well-being, and quality of life of individuals, communities, or populations. These stressors can come from one or more sources in the built, natural, and social environments and can accumulate over time. Cumulative impacts can be positive or negative. For example, in communities that are already overburdened, unequal environmental conditions and exposure to multiple stressors can lead to disproportionate impacts.”

A person or organization receiving services from the Air District. Services can include air quality permits, public records, grant funding, or air quality information. Members of the communities whose air quality we work to improve, are also our customers.

Differences in level or treatment, especially ones that are seen as unfair.

Environmental justice has two primary types of definitions – one type generated by the advocacy community and one generated by government, including the United States Environmental Protection Agency. Both are valuable in understanding environmental justice.

The Environmental Protection Agency defines environmental justice as, “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. This goal will be achieved when everyone enjoys the same degree of protection from environmental and health hazards, and equal access to the decision-making process to have a healthy environment in which to live, learn, and work.”

Dr. Bunyan Bryant, a pioneering environmental justice scholar, defines environmental justice as “…cultural norms and values, rules, regulations, behaviors, policies, and decisions [that] support sustainable communities where people can interact with confidence that the environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential … where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.”

The environmental justice movement was galvanized in 1987, when the United Church of Christ Commission released a study demonstrating that, across the country, toxic facilities were consistently located in Black and Brown communities. In 1991, delegates to the First National People of Color Environmental Leadership Summit drafted and adopted The Principles of Environmental Justice, and it has served as a defining document for the growing environmental justice movement.

Dr. Benjamin F. Chavis Jr, a civil rights leader, coined the phrase and defined it to mean the intentional siting of polluting and waste facilities in communities primarily populated by African Americans, Latines, Indigenous People, Asian Americans and Pacific Islanders, migrant farmworkers, and low-income workers.

The quality of being fair and impartial. In environmental justice work, equity is also often defined as increasing access to power, redistributing, and providing additional resources, and eliminating barriers to opportunity, to empower low-income communities of color to thrive and reach full potential.

In the content of Air District regulations and permitting, a regulatory exemption means that a source or facility that produces air pollution does not have to comply with one or more requirements in a regulation or that the facility or source is not subject to the regulation (for example, if the source is subject to another regulation or if its emissions or possible emissions of air pollution are below a certain level). A permitting exemption means that a source or facility or piece of equipment is not required to receive a permit to operate (for example, because the emissions or possible emissions of air pollution are below a certain level). A source or facility or piece of equipment may be exempt from permitting but still be subject to one or more Air District regulations.

Tiny particles suspended in the air, which vary greatly in terms of their size and mass, physical state (solid or liquid), chemical composition, toxicity, and how they behave and transform in the air. Particles can be made up of various substances such as dust, pollen, soot, and smoke. Particulate matter can penetrate deep into the lungs and cause respiratory problems.

Plans required by the Air District for all industrial operations that use flare systems. Plans describe each flare at a given facility, the equipment and procedures used to reduce flaring, and any other measures needed to prevent flaring.

Flare systems at oil refineries are used to safely dispose of hydrocarbon gases. The flare systems gather the vented gases and combust them to keep them from being released directly into the air. Flaring may result from the start-up and shutdown of equipment, during accidents, or because of equipment malfunctions.

Any gas that traps some of Earth’s outgoing energy, thus retaining heat in the atmosphere. Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, halogenated fluorocarbons, ozone, perfluorocarbons, sulfur hexafluoride, and hydrofluorocarbons.

A process that uses multiple data sources and analytic methods, including input from community members, to determine the potential effects of a proposed policy, plan, program, or project on people’s health and the distribution effects within a community.

Low-cost air pollution sensor networks, such as Purple Air, can provide information about air quality on a neighborhood-by-neighborhood basis. Low-cost sensors often report data on time scales shorter than an hour, and therefore can provide information about rapid changes in air quality, which can be useful in certain cases, like during wildfire smoke episodes.

The Air District recommends using the official Air Quality Index, calculated from Air District monitoring data when assessing whether the air quality in your area is safe. Low-cost sensor data, however, can be used to determine whether air quality is getting worse. Using Air District monitoring data along with low-cost sensors can provide a more robust understanding of when and where poor air quality conditions may be occurring.

A permit required by a section of the 1990 modifications to the federal Clean Air Act for certain large sources of air pollution requires. This permit, which is enforceable by the United States Environmental Protection Agency and by citizens, contains all applicable requirements under the Clean Air Act.

Any motor vehicle or moving equipment that produces air pollution. Examples include cars, trucks, motorcycles (also known as on-road mobile sources) or airplanes, trains, and construction equipment (also known as off-road mobile sources).

Treating individuals or groups differently based on perceived differences, such as ethnicity, religion, gender, sexual orientation, or other characteristics.

Policies and practices that financing entities and governments deployed to segregate communities of color in “declining” neighborhoods while reserving the “best” and most “desirable” neighborhoods for whites. 

The California Air Resources Board’s 2022 Scoping Plan is, “A statewide plan to reduce greenhouse gas emissions by 85 percent and achieve carbon neutrality by 2045. The plan provides a detailed sector-by-sector roadmap to move the state away from its dependence on petroleum and fossil gas to clean and renewable energy resources and zero-emission vehicles.”

A fixed, non-mobile producer of pollution, usually at industrial or commercial facilities. Examples include gas stations, oil refineries, restaurants, auto-body shops, recycling facilities, and wastewater treatment plants.

Air pollutants identified by the California Air Resources Board that may cause or contribute to an increase in deaths or serious illness, or that may pose a present or potential health hazard. Health effects may occur at extremely low levels of toxic air contaminants