SACRAMENTO —  California regulators voted on Thursday to ban the sale of new gas-powered leaf blowers and lawn mowers starting in 2024 and portable generators by 2028, the latest step in the state’s aggressive effort to reduce harmful pollutants and transition toward a carbon-free economy. The new regulations by the California Air Resources Board require all newly sold small-motor equipment primarily used for landscaping to be zero-emission by the target dates, with some exceptions. The agency’s decision is based in part on the belief that battery technology will improve and zero-emission gear will become more widely available before the requirements kick in — though there will be an annual review to…