If it costs some services more to upgrade than others then they will be in trouble. If enforcement is nonuniform than it will also be an issue. But if both of

If it costs some services more to upgrade than others then they will be in trouble. If enforcement is nonuniform than it will also be an issue. But if both of these can be controlled then it's really just those consumers that could only barely afford a lawn service in the first place that get left in the cold. Enforcement shouldn't be excessively difficult. Cops can write citations for illegal equipment, and if a company routinely ignores the citations they could get in real trouble. Give the companies plenty of time (a year or two) to phase in the new equipment as well. Make sure the change is well publicized, especially in Hispanic media. If the city was really proactive they could task an intern with calling every lawn service company in the city 6 months before the law goes into effect and make sure each one has a plan to transition in time. The enforcement is key however. These sorts of regulations will be ignored 100% if they aren't enforced. Escalating fines are necessary, they have to make it more expensive to break the law than comply, or the companies that cheat will win.