As Louisville celebrates the Fourth of July, there will be both Metro-sanctioned and rogue fireworks displays. In the past, this has often caused uncharacteristically high air pollution in the city.These days, Louisville has issues with some kinds of air pollution. When you hear about an air quality alert, it’s almost always for high ozone levels. Particle pollution—or soot—levels in the city’s air have been fairly low in recent years.But that’s every day other than July 4, and sometimes during Thunder Over Louisville. Fireworks cause soot, which causes the city’s particle pollution monitors to spike. Air Pollution Control District spokesman Tom Nord says these spikes count when the federal government looks at the city’s air quality, but they generally aren’t enough to throw Louisville out of compliance with air quality standards.“These are brief episodes, they’re not really indicative of the entire overall air quality of the area,” he said. “You have a big fireworks show downtown, but you also have little fireworks shows going on all over the area. But it’s kind of considered an episodic, one-time thing.”This year, the weather is forecast to be cooler and rainier than in years past, which could also help move any soot pollution away from the city faster. That's good news, but of course fireworks release a number of other nasty chemicals into the air, too.Be safe and protect your body--including your lungs--if you're going to shoot any off.