Acceptable types include face masks and cloth face covering. Very few people are exempt from wearing a cloth face covering in Los Angeles including children under the age of 2, those with breathing difficulties, or those instructed not to use one by a medical provider.
N-95 or KN-95 face masks are the most effective face coverings, but due to limited supply should be reserved for healthcare workers and essential workers. Surgical face masks are more readily available for public use.
Copper has not been extensively studied, but two layers of coffee filters have been shown in studies to improve the efficacy of homemade cloth masks, but the most important part of any mask is that it should fit snugly against your face with no gaps.
Source: LA Public Health