Vulnerable Populations Chronic Conditions Children's Health Asthma Chronic Diseases Public Health Toxic Substances Sensitive Groups Symptoms Chronic Illnesses Cardiovascular Diseases Ailments Life Expectancy Preventive Measures Child Health Breathing Discomfort Breathing Disorders Particulate Matter Exposure Breathing Difficulties Chronic Respiratory Diseases Nanoparticle Exposure Cardiovascular Issues Health Risks Public Health Guidelines Long-term Exposure Noxious Gases PM2.5 Ozone Exposure Sensitive Populations