That's why summertime is the time to watch out for unhealthy levels of ozone. Wind direction also affects ozone and other air pollution levels. On hazy, hot and humid summer days, winds in New Jersey are usually blowing from the southwest. These winds carry air pollution from the Washington, Baltimore and Philadelphia metropolitan areas to New Jersey, contributing to high ozone levels here. These winds also carry the pollution created here to New York, Connecticut and further to the northeast.
Weather can also affect how quickly pollutants move away from an area.
Normally, pollutants rise or blow away from their sources without building up to unsafe amounts. But imagine what could happen if the air was trapped inside a giant box. The pollutants can't escape, and after a while they may build up to unhealthy levels. Inversions can even occur on clear summer nights. This can affect the next day's ground-level ozone concentrations.