Countries may undergo concentration.Logical formLearned from9 sentences. Environmental contaminants may undergo concentrations.Logical formLearned from9 sentences. Lignin may undergo concentrations.Logical formLearned from9 sentences. Cobalt may undergo concentration.Logical formLearned from9 sentences. Carbonate may undergo concentrations.Logical formLearned from9 sentences. Concentrations can be unhealthy.Logical formLearned from9 sentences. Milligrams may undergo concentrations.Logical formLearned from9 sentences. Particulate may undergo concentration.Logical formLearned from9 sentences. Persons may see concentration.Logical formLearned from9 sentences. Concentration can be a factor.Logical formLearned from9 sentences. Aerosol may undergo concentration.Logical formLearned from9 sentences. Concentration can be monopolistic.Logical formLearned from9 sentences. A body may depend upon a (blood alcohol concentration).Logical formLearned from9 sentences. An (ozone concentration) can be ambient.Logical formLearned from9 sentences. (Carbon dioxide concentrations) can be indoor.Logical formLearned from9 sentences.