Fourth of July 🇺🇸, Canada Day 🇨🇦, Bastille Day 🇫🇷… seems like half the world is out celebrating this month! And where there’s a festival, there are fireworks. Not to be a killjoy, but pollution can come from unlikely places. So how badly do fireworks affect air quality? 🎆

Our in-house Atmospheric Scientist ran the numbers in Los Angeles this Independence Day. The graph above shows some heavy ozone pollution that afternoon – reasonably common in summer. That big spike in the evening though? Particulate matter. Likely due to smoke from this year’s display.

While this means those with sensitivities should take extra care during fireworks shows, most of us shouldn’t sweat it too much. Pollution above 100 on our Plume Index only becomes harmful if breathed in for more than an hour. Cumulative exposure is what’s important, and the peak is mostly gone by morning!

However, an extra PM peak can conspire with existing pollution cycles to ruin what would otherwise be a fresh air moment. Take a look at the graph below showing our overall Plume Index for LA – it takes its value from the pollutant most affecting your health at any given moment. You can see that a cumulative effect begins to stack up.

Firework peaks also depend on the weather. It rained in Washington DC this 4th of July, so any fumes from the fireworks were quickly washed away.

Tracking your cumulative exposure will soon be an everyday activity thanks to Flow, our smart mobile air quality tracker. Pre-order now to be the first to pick one up.

Want a closer look at LA pollution on the day-to-day? Follow @PlumeinLA or download our free Plume Air Report application for iOS or Android.