Police in the Des Moines metro said they responded to more fireworks complaints this Fourth of July, but there were few citations issued during Iowa's first year for legal fireworks since before World War II.

Des Moines police received 441 fireworks-related calls between midnight Monday and 4 a.m. Wednesday. That's 21 more complaints than last year and 147 more than in 2015.

Sgt. Paul Parizek said he did not have data on the number of citations issued.

"I'd be surprised if we had the time (for citations)," he said. "It would have to be something pretty serious, because we're going to 441 calls on top of everything else we're doing."

West Des Moines police responded to 200 fireworks calls, 130 more than last year, said Sgt. Anthony Giampolo, spokesman for the department.

Des Moines and West Des Moines both allowed a six-hour window for residents to shoot fireworks from 4 to 10 p.m. on July 4, but Giampolo said officers saw a spike in activity on Monday evening, the day before the holiday.

"They got bombarded on their 10-hour shift with about 30 calls," he said. "They thought that was a little higher than usual for them."

Former Iowa Gov. Terry Branstad signed legislation in May lifting the state's ban on most consumer fireworks. The law allows residents to buy and use fireworks for a period around the Fourth of July and again before New Year's Eve.

Despite the easing of state restrictions, many Iowa cities passed limits on when and where fireworks can be used.

In Clive, where fireworks are outright banned, police responded to 47 complaints, but no citations were issued. Clive police fielded 14 fireworks calls last year.

Offenders can face up to a $625 fine depending on where they live.

But actually finding people who set off fireworks illegally can be challenging, said Lt. Brian Kroska, spokesman for Ankeny Police Department.

Police who see fireworks on the horizon can go find them, but "it gets to a point where you're possibly chasing your tail," he said. It's also difficult to figure out who actually was lighting the fireworks once police respond to a complaint.

"You want to cite the offender," Kroska said.

Ankeny allowed fireworks between 9 a.m. and 11 p.m. on July 4. Police only received two complaints after that window had ended, he said.

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The Des Moines Fire Department responded to two fireworks-related fires Tuesday. A dumpster on the city's south side was found ablaze in the afternoon. Firefighters found discarded fireworks material in the receptacle after it was extinguished, said Ted Jefferson, fire prevention inspector.

Then, at about 11:45 p.m., officials responded to a home in the 2800 block of Columbia Street where a neighbor had extinguished a mattress that caught fire. Jefferson said the homeowner admitted to lighting fireworks that caught the mattress, which was next to the house. Officials reported some damage to the home's siding.

And according to Mercy Medical Center's Emergency Department, the number of fireworks-related injuries — all nine of which were minor — was on par with previous years.

Air quality alert issued

An air quality alert was issued in the Des Moines metro on Wednesday morning.

An increase in fine particle pollution levels began around dusk on the Fourth of July and persisted overnight, according to a news release from the Iowa Department of Natural Resources.

Fireworks likely contributed to the increase, though the DNR does not track official causes of air quality alerts.

The air quality alert specifically targeted "sensitive groups," including asthmatics, those with respiratory difficulties, the elderly, children and pregnant women.

Lingering smoke was expected to move out of the metro by noon as wind speeds picked up, the DNR said.