Requires sellers of real property containing up to four residential units to complete a disclosure form indicating the presence of all environmental hazards, including radon gas, formaldehyde, and mold, that are known to the seller. Also requires disclosure of whether property contains a carbon monoxide device. Requires resale of manufactured homes and mobile homes to include disclosure of environmental hazards in the home interior or exterior, including radon, formaldehyde, and lead-based paint, as well as the existence of a carbon monoxide device.

Establishes that no person may provide radon services for the general public unless that person has completed the National Radon Measurement Proficiency Program of the National Environmental Health Association or the National Radon Safety Board Certified Radon Professional Program. Requires certification of completion of either course to the state health agency, and requires the agency to make available to the public a list of individuals so certified.

Requires the state to prepare a booklet to educate consumers about common environmental hazards affecting real property, including radon. Separate law (Cal. Health § Safety Code § 25417.1) required the state to update the booklet.

Provides that the state health agency may develop radon assessment and mitigation requirements for new construction in at-risk areas.

Required the state health agency, through its Indoor Air Quality Program, to develop non-binding guidelines for the reduction of exposure to volatile organic compounds from construction materials in newly constructed or remodeled office buildings. (Guidelines available at: https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/EHLB/IAQ/Pages/VOC.aspx#publications.)

Requires the state health agency to conduct and promote the coordination of research, investigations, experiments, demonstrations, surveys, and studies relating to the causes, effects, extent, prevention, and control of indoor pollution.

Requires the state health agency to consider the feasibility of adopting permissible exposure limits to mold in indoor environments and, if feasible, to adopt such limits. Establishes criteria to consider in adopting standards, and provides that the department may also adopt alternative standards for facilities that serve people at greater risk. Provides that the law shall be implemented only to the extent that the department determines that funds are available for its implementation. Authorizes local enforcement of any standards adopted by the department.

Required the California Research Bureau, in consultation with the Department of Public Health and with the assistance of a review panel, to perform a study and to publish findings on fungal contamination affecting indoor environments. Required the study to include information on health effects, assessment, remediation, and hazard communication, among other issues. Required the California Research Bureau to submit its findings to the legislature and the Director of Public Health.

Required the Air Resources Board and the Department of Public Health to conduct a comprehensive study and review of the environmental health conditions in portable classrooms. Directed the study to include a review of design and construction specifications; a review of school maintenance practices; an assessment of IAQ; and an assessment of potential toxic contamination, including mold contamination. Required the study to address the need for modified design and construction standards; emission limits for building materials and classroom furnishings; and other mitigation actions to ensure the protection of children's health. (Report available at: https://ww2.arb.ca.gov/resources/documents/california-portable-classrooms-study.)

Requires the Air Resources Board, when evaluating the level of potential human exposure to toxic air contaminants, to assess exposure in indoor environments as well as in ambient air conditions. Requires the Board to coordinate with other state agencies.