Volatile Organic Compounds (VOCs)
Carbon-containing chemicals that easily evaporate at room temperature and contribute to ozone formation and direct health effects.
Detailed Explanation
Volatile organic compounds are a large group of carbon-based chemicals that evaporate easily at room temperature. They are emitted by a wide variety of sources, including vehicle exhaust, gasoline vapors, industrial solvents, paints, cleaning supplies, pesticides, building materials, and natural sources such as trees (which emit isoprene and terpenes). While not directly measured by the AQI, VOCs are critical to air quality because they are a key precursor in the formation of ground-level ozone. When VOCs react with nitrogen oxides (NOx) in the presence of sunlight, they produce ozone — the primary component of smog. Some VOCs are also direct health hazards. Benzene, formaldehyde, and perchloroethylene are known or probable carcinogens. Others cause headaches, nausea, and irritation of the eyes, nose, and throat. Indoor VOC concentrations can be substantially higher than outdoor levels due to emissions from furniture, flooring, paint, and consumer products — a phenomenon sometimes called "off-gassing." In cities where ozone is the dominant pollutant, VOC reduction strategies are a key part of air quality management. The EPA regulates VOC emissions from industrial sources, vehicle fuel systems, and consumer products. AirHistory does not directly track VOC levels, but ozone trends in city data are an indirect indicator of VOC and NOx activity in the local atmosphere.
Related Terms
Ozone (O3)
A reactive gas formed at ground level when sunlight triggers chemical reactions between nitrogen oxides and volatile organic compounds.
Smog
Visible air pollution, primarily composed of ground-level ozone and fine particles, that reduces visibility and harms health.
Indoor Air Quality
The quality of air inside buildings, which can be 2-5 times more polluted than outdoor air due to poor ventilation and indoor sources.
Emissions Inventory
A comprehensive accounting of air pollutant emissions from all sources in a geographic area, used for regulation and planning.
Frequently Asked Questions
Carbon-containing chemicals that easily evaporate at room temperature and contribute to ozone formation and direct health effects.
Volatile organic compounds are a large group of carbon-based chemicals that evaporate easily at room temperature. They are emitted by a wide variety of sources, including vehicle exhaust, gasoline vapors, industrial solvents, paints, cleaning supplies, pesticides, building materials, and natural sources such as trees (which emit isoprene and terpenes). While not directly measured by the AQI, VOCs are critical to air quality because they are a key precursor in the formation of ground-level ozone.