AQI
Category |
Ozone
(O3) |
Fine Particles
(PM2.5) |
Carbon Monoxide
(CO) |
Sulfur Dioxide
(SO2) |
| Good |
None |
None |
None |
None |
| Moderate |
Unusually sensitive individuals may experience respiratory symptoms. |
None |
None |
None |
Unhealthy for
Sensitive Groups |
Increasing likelihood of respiratory symptoms and breathing discomfort in active children and adults with respiratory disease, such as asthma. |
Increasing likelihood of respiratory symptoms in sensitive individuals, aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly. |
Increasing likelihood of reduced exercise tolerance due to increased cardiovascular symptoms, such as chest pain, in people with cardiovascular disease. |
Increasing likelihood of respiratory symptoms, such as chest tightness and breathing discomfort, in people with asthma. |
| Unhealthy |
Greater likelihood of respiratory symptoms and breathing difficulty in active children and adults and people with respiratory disease, such as asthma; possible respiratory effects in general population. |
Increased aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; increased respiratory effects in general population. |
Reduced exercise tolerance due to increased cardiovascular symptoms, such as chest pain, in people with cardiovascular disease. |
Increased respiratory symptoms, such as chest tightness and wheezing in people with asthma; possible aggravation of heart or lung disease. |
| Very Unhealthy |
Increasingly severe symptoms and impaired breathing likely in active children and adults and people with respiratory disease, such as asthma; increasing likelihood of respiratory effects in general population. |
Significant aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; significant increase in respiratory effects in general population. |
Significant aggravation of cardiovascular symptoms, such as chest pain, in people with cardiovascular disease. |
Significant increase in respiratory symptoms, such as wheezing and shortness of breath, in people with asthma; aggravation of heart or lung disease. |
| Hazardous |
Severe respiratory effects and impaired breathing likely in active children and adults and people with respiratory disease, such as asthma; increasingly severe respiratory effects likely in general population. |
Serious aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly; serious risk of respiratory effects in general population. |
Serious aggravation of cardiovascular symptoms, such as chest pain, in people with cardiovascular disease; impairment of strenuous activities in general population. |
Severe respiratory symptoms, such as wheezing and shortness of breath, in people with asthma; increased aggravation of heart or lung disease; possible respiratory effects in general population. |
