Questions like this one test your ability to recognize potential legal issues, weed out irrelevant facts, and exercise judgment about whether claims and defenses are likely to be successful. Lomax is seeking an injunction or, in the alternative, damages for the harm caused by chemical production at the plant.
Courts allow trespass actions for any physical intrusion, no matter how slight.
Trespass is a good basis for Lomax's claim, because it doesn't permit the court to balance the interests of the chemical plant, including public interest. The problem with Giant's reliance on that case, of course, is that the same court decided a case involving fumes and particles emitted from a paper mill as a matter of trespass law, on the theory that the particles landing on the plaintiffs' land were a sufficient physical intrusion to constitute a trespass. Despite the attractiveness of a trespass theory for Lomax, and the result in Davis , however, most courts handle toxic-exposure cases under a nuisance theory, not trespass. It just seems to strain the notion of trespass to allow recovery for increasingly fine sizes of particles. Unreasonableness is where you may get into the balancing of equities.