Emerging Air Toxics of Concern
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Toxic air pollutants, also known as air toxics, are chemicals that can cause cancer or other serious health effects when people are exposed to them in the air. As scientific knowledge and chemical use evolve, some pollutants are identified as potentially posing greater risks than previously understood. These pollutants are referred to as emerging air toxics.
Emerging Air Toxics include air toxics that have:
- newly identified toxicities not previously understood, including quantified health values
- recently detected in the environment through air monitoring studies and usage
- recently found to be accumulating in the bodies of humans identified through biomonitoring studies
This website will provide information and resources for emerging air toxics of concern. Recent emerging air toxics of concern include:
Acrolein
On May 14, 2026, the Office of Health Hazard Assessment (OEHHA) released a new draft cancer risk value for acrolein.
Resources:
Frequently Asked Questions (FAQ)
Factsheet (coming soon)
Ethylene Oxide
On May 14, 2026, the Office of Health Hazard Assessment (OEHHA) released a draft cancer risk value for ethylene oxide (EtO).
Resources:
Frequently Asked Questions (FAQ)
Factsheet (coming soon)
Methyl Bromide
Methyl bromide is a toxic air contaminant that can affect the respiratory and nervous systems. In 2023 air monitoring around fumigation operations near residential neighborhoods identified releases of methyl bromide (MeBr). For more information regarding the ambient air monitoring for MeBr please refer here: https://ww2.arb.ca.gov/capp/cst/ch2/wcwlb/methyl-bromide
Other Toxic Air Contaminants
A Toxic Air Contaminant (TAC) is an air pollutant which may cause or contribute to an increase in mortality or an increase in serious illness, or which may pose a present or potential hazard to human health. Under the state’s Toxic Air Contaminant Identification and Control Act, TACs are identified through a formal health evaluation process led by the Office of Environmental Health Hazard Assessment (OEHHA) and the California Air Resources Board (CARB). Once a substance is identified as a TAC, it may move into a risk management phase where strategies are developed to reduce or eliminate public exposure. Please note not all emerging toxics of concern have been formally identified as a TAC.