NEW ORLEANS — The Louisiana Department of Environmental Quality has issued an air quality alert again for most of the New Orleans metro area and South Shore for Thursday until 7 p.m.. St. Tammany Parish is also included.
The forecast for Thursday calls for a Code Orange, which means air quality could become unhealthy for sensitive groups, including children, the elderly, and those with respiratory diseases such as asthma. The forecast Air Quality Index Wednesday is 101, just inside the threshold for a Code Orange which is from 101 to 150. While a Code Orange doesn’t mean these groups should avoid the outdoors, they may need to think twice before prolonged exertion during the afternoon.
High pressure has taken over the northern Gulf Coast and will remain in place all week. This will cause sinking air from the atmosphere and calmer winds. Combined with the heat we’re seeing, ozone is likely to collect at the surface which could cause issues for those in the sensitive groups. While ozone is helpful in the upper atmosphere at keeping ultraviolet rays away, it is not healthy to breathe so its presence can be an issue at the Earth’s surface.
By Friday, an onshore flow from the Gulf of Mexico should help limit the collection of pollutants at the surface. The stronger the winds, the stronger the atmospheric mixing is, and the less likely ozone or smog is to collect where we breathe.
The parishes included in the alert are: Jefferson, Orleans, Lafourche, Plaquemines, St. Bernard, St. Charles, St. John the Baptist, St. Tammany, and Terrebonne Parishes.