Some of the major sources of NOx and VOC are waste products emitted by cars, power plants, industrial boilers, refineries and chemical plants. Metropolitan areas are prone to high levels of ozone, but no region is immune. But even the smallest amounts of ground-level ozone can be damaging to lung tissue. At the end of the bronchioles are tiny air sacs called alveoli, which fill up and expand like little balloons to put oxygen into the bloodstream. Ozone primarily injures these key oxygen exchangers.
Ozone affects people differently, based on their susceptibility.
But generally speaking, in the event of an ozone alert, outdoor activities should be scheduled for morning or early evening hours to avoid the mid-day peak when levels are at their highest. Ozone also affects the environment, plants and animal life. Scientists say ground-level ozone affects plant health by weakening vegetation and making plants more susceptible to disease, pests and stress. Researchers believe that over time, ground-level ozone can affect entire forests or ecosystems by impacting water movement, mineral nutrient cycling and habitats for animal and plant species. The AQI converts the measured pollutant concentration in the air to a number on a scale of 0 to 500.