The relationship between air pollution, weather, and symptoms in an urban population. Clarification of conflicting findings.

Abstract

Numerous studies have documented a relationship between air pollution, weather, and illness. Specific causes proposed to account for the effects have not stood up to critical examination, and the nature of the relationships has remained obscure. Indeed, contradictions and paradoxes are common within the general association between the environment and illness. The findings reported here support the belief that the environment—like some other modern health problems—must be examined differently than has been customary in the search for health effects, employing changed ideas of causality. The concept of the multiplex variable and some aspects of the philosophy of causality are discussed.