California Code, Health and Safety Code - HSC § 39619

(a) Recent scientific studies have documented significant adverse public health effects associated with exposure to airborne fine particles that are smaller than 2.5 microns (PM 2.5).

(b) Federal ambient air quality standards for the control of particles smaller than 10 microns in diameter (PM 10) will require additional emission controls in California.

(c) California's existing ambient air quality monitoring program for PM 10 and PM 2.5 provides inadequate scientific information with regard to the level of public exposure to, and public health risk from, airborne fine particles, and therefore must be expanded and improved to evaluate priorities and establish appropriate control strategies.

(d) Current proposals for required monitoring of PM 2.5 by the Environmental Protection Agency may not be appropriate for properly measuring species of pollutants that comprise the principal components of airborne fine particles within the state.

(e) California needs to develop an airborne fine particle monitoring program that reflects the specific nature of California's fine particle air pollution problem and develops data suitable for use in exposure evaluations.

(f) California should use the most accurate methods available in the fine particle monitoring program that are appropriate for use in California and should strive to avoid duplication of the federal air monitoring program whenever possible.