Ambient particulate pollution during Chinese Spring Festival in urban Lanzhou, Northwestern China

The effect of firework displays on ambient particulate pollution in a typical valley city in Northwestern China was evaluated based on high temporal resolution atmospheric particle size distribution (10–10 000 nm) data and particle mass concentrations in different sizes obtained during 25th January – 24th February, 2013. Firework displays have significant impact on particle number concentrations in accumulation mode (100–1 000 nm), especially in 200–500 nm, as well as PM1 mass concentrations. The hourly mean number concentration in 200–500 nm and PM1 mass concentration during the peak hour of firework displays were 11 800.2 ± 2 548.0 cm–3 and 214.1 ± 31.2 μg m−3, which are approximately 6 times and 2 times of that before the festival, respectively, with a maximum10–min mean number concentration in size range 100–1 000 nm reaching 3.8 × 104 cm−3 on the New Year's Eve (00:10 BT 10th February, 2013). It was estimated that local emissions and firework displays contributed 74.6% and 37.0%, respectively, to the number concentration of particles less than 1 000 nm. On short–time scale, the contribution of firework displays on local particulate pollution is obvious and should not be ignored, especially on fine particulate pollution.