Kudos to Miguel Bustillo for that LA Times story on smog and cows. I’ve dealt with Miguel on several California smog stories in the past, and he is good about reporting aspects (like this one) that most enviro beat reporters won’t.
Once again, we see another vindication of Reagan’s view that there were lots of natural (or non-human) sources of smog. About 15 years ago the LA smog regulators did a study of emissions from trees, and concluded that they might not be able to meet the Clean Air Act targets for the LA basin unless they began to regulate . . . landscaping. The Times reported this quite well; It turned out that Japanese trees were lower-emitting trees than native American trees. The head of Tree People, a local tree-planting group, told the Times that they were very concerned, but would be sure to make sure that their members “planted low-emitting trees.” Evelyn Waugh could hardly have written better satire.