A number of studies, including the study of six cities, suggest that the largest particles are the most dangerous because they can invade the body's natural defenses and penetrate deeply into the lungs, becoming a chronic source of irritation.

Question

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The smallest particles, not the largest, are considered the most dangerous because they can evade the body's natural defenses and penetrate deeply into the lungs, potentially causing more severe health issues.

A Number of Studies, Including the Study of Six Cities