How do fine particles affect public health?
Because of its very small size, fine particles (soot) are easily inhaled deep into the lungs where they can remain embedded for long periods of time. For those people with lung diseases or respiratory illnesses like asthma or chronic obstructive pulmonary disease, fine particles can aggravate the diseases. Exposure to fine particle pollution can trigger asthma flare-ups and causes wheezing, coughing and respiratory irritation in individuals with sensitive airways.

Fine particles can also affect people with heart disease. Exposure to high levels of fine particles can trigger serious problems in a short period of time – even heart attacks – with no warning signs. Symptoms such as chest pain or tightness, palpitations, shortness of breath or unusual fatigue may indicate a serious problem.

Even healthy individuals may experience temporary symptoms such as irritation of the eyes, nose and throat; coughing' phlegm; chest tightness and shortness of breath from increased levels of particle pollution.

Who is more at-risk when fine particle levels are high?
Older adults are at increased risk, possible because they may have undiagnosed heart or lung disease or diabetes. Many studies show that when fine particle levels are high, older adults are more likely to be hospitalized, and some may die of aggravated heart or lung disease.

Children are likely at increased risk for several reasons. Their lungs are still developing; they spend more time at high activity levels; and they are more likely to have asthma or acute respiratory diseases, which can be aggravated, when particle levels are high.

It appears that risk varies throughout a lifetime, generally being higher in early childhood, lower in healthy adolescents and younger adults, and increasing in middle age through old age as the incidence of heart and lung disease and diabetes increases. Factors that increase risk of heart attack, such as high blood pressure or elevated cholesterol levels, also may increase risk from fine particles.

In addition, scientists are evaluating new studies that suggest that exposure to high particle levels may also be associated with low birth weight in infants, pre-term deliveries and possibly fetal and infant deaths.

What is the Air Quality Index?
The Air Quality Index, or AQI, is a tool used for reporting daily air quality. Levels of five major pollutants – ground-level ozone (smog), fine particles (soot), carbon monoxide, sulfur dioxide and nitrogen dioxide – are monitored and are used to provide the overall AQI score.

This score offers a glimpse as to how much pollution is in the area and what health effects may be noticeable. An AQI of 100 usually represents the national air quality standard that the EPA has set to protect public health. As a general rule, the higher the AQI value, the more air pollution and health risks there are.

For more information about the AQI, please visit the EPA's AIRNow website by clicking here.

• Ask employees to monitor their health during high fine particle days. If they cough regularly, experience shortness of breath or experience chest pain or tightness, have them consult their physician.
• Limit or discontinue pollution-causing operations that are non-essential on days when air pollution levels are high.
• Stay away from busy roads and other sources of air pollution when possible.
• Avoid places with poor indoor air quality, such as smoky bars, workplaces or restaurants.
• Use indoor air conditioning when possible.
• Check the Air Quality Index (AQI) by called (317) 327-4AIR or by visiting the Knozone website. Communicate pollution levels to your employees throughout the day.