Are Environmentally Friendly Fireworks Really "Green" for Air Quality? A Study from the 2019 National Day Fireworks Display in Shenzhen.

Fireworks are widely used around the world and can cause severe air pollution over a short period of time. Many efforts have been carried out worldwide to reduce the level of firework-generated air pollution, such as limiting the use of fireworks and developing environmentally friendly fireworks. Research has suggested that the use of environmentally friendly charges in fireworks can reduce emissions, although their impact on ambient air quality has not been quantified. Here, we used a chemical transport model to study the benefits of environmentally friendly fireworks in reducing ambient PM2.5 based on a detailed estimation of emissions from fireworks and dense observations available for simulation validation. Our results showed that environmentally friendly fireworks can reduce ambient PM2.5 by ∼50% (in the range of 15-65% with a "central" value of 35% considering uncertainties) compared with traditional fireworks. However, due to a large number of fireworks used, the air quality still significantly deteriorated, and the effect of using twice the amount of environmentally friendly fireworks on air quality would be comparable to the use of traditional fireworks. Our results indicate that environmentally friendly fireworks are not actually "green". To make them green, the total number of fireworks used at one time must be strictly restricted.