Air quality health advisory in effect until 11 p.m.

An air quality health advisory is in effect again today for the Long Island region through 11 p.m.

Air quality will be “unhealthy for sensitive groups,” including the elderly, young children and people respiratory disease (such as asthma), who should consider limiting strenuous outdoor activities, according to the advisory.

The pollutant of concern is ozone, according to the advisory issued by the state commissioners of environmental conservation and health.

Air quality health advisories are issued when DEC meteorologists predict levels of pollution, either ozone or fine particulate matter, are expected to exceed an air quality index (AQI) value of 100. The AQI was created as an easy way to correlate levels of different pollutants to one scale, with a higher AQI value indicating a greater health concern.  The AQI for Long Island today is 101.

Summer heat can lead to the formation of ground-level ozone, a major component of photochemical smog, according to the advisory. Automobile exhaust and out-of-state emission sources are the primary sources of ground-level ozone and are the most serious air pollution problems in the northeast, the advisory said. This surface pollutant should not be confused with the protective layer of ozone in the upper atmosphere.  

People, especially young children, those who exercise outdoors, those involved in vigorous outdoor work and those who have respiratory disease (such as asthma) should consider limiting strenuous outdoor physical activity when ozone levels are the highest (generally afternoon to early evening). When outdoor levels of ozone are elevated, going indoors will usually reduce your exposure. Individuals experiencing symptoms such as shortness of breath, chest pain or coughing should consider consulting their doctor.  

Ozone levels generally decrease at night and can be minimized during daylight hours by curtailment of automobile travel and the use of public transportation where available.