According to an Irvine University study, fireworks have become synonymous with Independence Day celebrations. However, the public is now more at risk from these colorful displays.Scientists from UCI's Program in Public Health rely on real-time air quality measurements crowdsourced using a network more than 750 automated sensors distributed across California. They found that the short-term, extremely harmful-particulate matter air pollution caused by the widespread use fireworks spiked in the months of late June through early juillet in 2019 and 2020.This was especially true in Southern California counties, where fireworks regulations are less strict than those in the northern part of the state. Also, illegal do-it-yourself fireworks use is more common. These and other findings were the subject of a recent study in the International Journal of Environmental Research and Public Health.Jun Wu, a UCI professor of public and health, said that while there have been discussions about pet owners worrying about fireworks on their homes, "we've discovered that the sky is filled with fireworks poses a real threat also to our well-being." "And as with many environmental justice issues, we find that the most severe impacts are felt by residents from low-income communities.Fine particles less than 2.5 millimeters in diameter are released by aerial explosions. This size of airborne particulate matter is dangerous because it can be inhaled and passed on to the lungs. The compounds barium, copper and magnesium are responsible for the unique colors of fireworks. These chemicals are released by rockets as they burst into the sky. They also release trace redox active metals and water-solubleions which fall on those below.Wu stated that fine particles can cause adverse health effects such as premature death, cardiovascular disease, poor pregnancy outcomes and neurological diseases.Data gathered by a network of PurpleAir sensors in the state, which are low-cost devices that are placed in homes, was used by the UCI team. The researchers used this method to create a map that tracked airborne particulate matter levels less than 2.5 millimeters in diameter, before, during, and after the Fourth of July fireworks.Amirhosein Mousavi (postdoctoral scholar in UCI’s Program in Public Health), said that PurpleAir's sensors continuously monitor the air. This is a significant advantage over traditional monitoring systems that are often located far from residential areas and may take intermittent measurements that might miss peak times like the Fourth of July. We were able to obtain a better understanding of the health hazards posed by DIY fireworks by using data from a distributed sensor network that collects data in different neighborhoods.The study found that Los Angeles County had the highest daily levels of PM2.5 in California, out of all the 58 counties. This was both for 2019 and 2020. This could be due to more people shooting their own rockets in their neighborhoods, or the topography of L.A., which has been known to encourage the accumulation of air pollution for many years.Researchers believe that they also detected a COVID-19-effect in their data. The average PM2.5 concentrations in 2020 on July 4th and 5th were 50 percent higher than those in 2019. This could be due to increased household fireworks use during pandemic lockdowns.The team discovered that peak fireworks pollution was twice as high in communities with lower socioeconomic standing, higher minority-group populations, and higher asthma rates.Wu stated that Wu's work "underlines the importance of policy and enforcement in reducing fireworks-related pollution and protecting public safety." "As fireworks regulations vary in each state, it is clear that people would be able to breathe more easily during celebrations if they had a coordinated approach."