All of these are barriers to me personally. First, areas where standards should have been included, but where none are in the proposal.
Source reduction is by far the most effective.
However, since the Board does not control such things as fragrance use by individuals, all three tactics are required. EMFs can also be reduced through the use of shielding. For the first time, the current proposed rule takes note of photosensitivity, as it relates to the flash rate of visual alarm devices. Meanwhile, other photosensitive triggers abound, such as fluorescent lights. Try going into a public building, if fluorescent lights trigger seizures for you.