California Code, Health and Safety Code - HSC § 43023.5

(a) Districts with a population of one million residents or greater, in consultation with the state board, shall ensure that not less than 50 percent of the funds appropriated for purposes of the programs specified in paragraphs (1) to (3), inclusive, are expended in a manner that directly reduces air contaminants or reduces the public health risks associated with air contaminants in those districts, including, but not limited to, airborne toxics and particulate matter, in communities with the most significant exposure to air contaminants or localized air contaminants, or both, including, but not limited to, communities of minority populations or low-income populations, or both:

(b) A district with less than one million residents is encouraged to expend funds available to the district for the purposes specified in subdivision (a) in a manner similar to that set forth in subdivision (a), to the extent that district determines that this is feasible.