Pollutant-Specific Health Effects Statements 
Pollutant Good Moderate Unhealthy for Sensitive Groups Unhealthy Very Unhealthy Hazardous
Ozone None Unusually sensitive
individuals may experience
respiratory symptoms.
Increasing likelihood of respiratory symptoms and
breathing discomfort in active children and adults and
people with lung disease, such as asthma.
Greater likelihood of respiratory symptoms and breathing
difficulty in active children and adults and people with lung
disease, such as asthma; possible respiratory effects in
general population.
Increasingly severe symptoms and impaired breathing
likely in active children and adults and people with lung
disease, such as asthma; increasing likelihood of
respiratory effects in general population.
Severe respiratory effects and impaired breathing likely in
active children and adults and people with lung disease,
such as asthma; increasingly severe respiratory effects
likely in general population.
PM2.5/PM10 None Respiratory symptoms possible in unusually
sensitive individuals, possible aggravation of heart
or lung disease in people with cardiopulmonary
disease and older adults.
Increasing likelihood of respiratory symptoms in
sensitive individuals, aggravation of heart or lung
disease and premature mortality in people with
cardiopulmonary disease and older adults.
Increased aggravation of heart or lung disease and
premature mortality in people with cardiopulmonary
disease and older adults; increased respiratory
effects in general population.
Significant aggravation of heart or lung disease and
premature mortality in people with cardiopulmonary
disease and older adults; significant increase in
respiratory effects in general population.
Serious aggravation of heart or lung disease and
premature mortality in people with cardiopulmonary
disease and older adults; serious risk of respiratory
effects in general population.
Sulfur Dioxide None None Increasing likelihood of
respiratory symptoms, such as
chest tightness and breathing
discomfort, in people with
asthma.
Increased respiratory
symptoms, such as chest
tightness and wheezing in
people with asthma; possible
aggravation of heart or lung
disease.
Significant increase in
respiratory symptoms, such as
wheezing and shortness of
breath, in people with asthma;
aggravation of heart or lung
disease.
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
Nitrogen Dioxide None None Increasing likelihood of
respiratory symptoms, such as
chest tightness and breathing
discomfort, in people with
asthma.
Increased respiratory
symptoms, such as chest
tightness and wheezing in
people with asthma; possible
aggravation of heart or lung
disease.
Significant increase in
respiratory symptoms, such as
wheezing and shortness of
breath, in people with asthma;
aggravation of heart or lung
disease.
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