This weekend — despite the heat and sunlight — we didn’t exceed the ozone standard. Today we have a guest post from our meteorology consulting team at Weather or Not, who provide the SkyCast during the ozone season, to explain why.
Sunshine, heat and southerly winds are typical triggers for high concentrations of ground level ozone. So why is it that Kansas Citians basked in the sunshine, felt the heat and southerly winds but didn’t see an Ozone Alert this weekend (June 11 and 12)?
Factors such as cloud cover, lower traffic on the weekends, rain potential and upwind pollution all played their part.
Cloud cover played a pivotal role in limiting local production of ozone. Sun is a key ingredient in the formation ozone, so when puffy cumulus clouds begin to build, ozone production either stalls or decreases. The hour of each day that the puffy cumulus clouds were building was the exact same hour that ozone monitors peaked. Since the EPA ozone standard is based on a running eight-hour average, the “fair weather” clouds helped to keep ozone levels from climbing too high.
Sunday’s scattered showers and thunderstorms also helped decrease ozone values. Thickly clouded, rainy afternoons are an environment that can stunt ozone production and keep levels within clean air limits.
Weekend traffic helped. Fewer cars on the road helped to minimize local ozone production Saturday and Sunday. During the weekdays, we have two peak travel periods (morning and evening) that can increase dirty air. On the weekend we don’t have rush hour traffic, which limits pollution levels that could lead to increased ozone production.
We got a little help from our friends. Our upwind pollution potential for the weekend originated from Dallas, Tulsa and Oklahoma City. Their ozone levels stayed at high green to low yellow values (Air Quality Index (AQI) values in the upper 40s to low 50s). Often when their levels are high for a few days, southerly winds will transport those high ozone concentrations into the Kansas City area. That didn’t happen this weekend.
While close monitoring of the Ozone Alert potential was necessary this weekend, Mother Nature did her part to keep ozone in check in Kansas City.
And you helped, too, if you limited driving and other emission-producing activities.