There’s an air quality alert in effect today, but that’s for ozone. Louisville’s air quality monitors showed spikes in another type of pollution last night, as fireworks were going off around the city.

Air Pollution Control District spokesman Tom Nord says the fireworks caused spikes in several area air pollution monitors.

“We’re already having problems with ozone, and we did have another exceedance yesterday for ozone,” Nord said. “But fireworks are mostly a particulate matter issue, it’s mostly a soot issue.”

Nord says in the scheme of Louisville’s air pollution issues, the higher amounts of particle pollution caused by the fireworks are a fairly small matter.

Federal law says the city’s particle pollution can’t exceed a certain amount—in this case, it’s 35 micrograms of pollution per cubic meter. For about an hour during fireworks celebrations, one of the air pollution monitors showed nearly three times that amount–100 micrograms of pollution per cubic meter. But the Environmental Protection Agency takes a 24-hour average of pollution, so often annual events like fireworks don’t officially trigger a violation.

“Obviously any time the air quality’s not as good as we want it to be, that’s a concern,” Nord said. “But the EPA does make allowances for the fact that with [particulate matter] you’re doing it on a 24-hour basis.”

Pollution levels spiked at monitors near Bates Elementary, Watson Lane, Southwick and Cannons Lane around 10 or 11:00 on the fourth.

It’s not yet known whether the pollution was enough to officially count as a pollution exceedence.