Influences of Beehive Firework Displays on Ambient Fine Particles during the Lantern Festival in the YanShuei Area of Southern Taiwan

This study investigates water-soluble ions in the sized particles (particularly Aitken nuclei mode (dp ≤ 0.1 μm, PM0.1)/ accumulation mode (0.1 < dp ≤ 1.0 μm, PM0.1–1.0)) collected using a MOUDI sampler in the YanShuei area of southern Taiwan during a beehive fireworks display. The results indicate that the PM2.5 and PM10 concentrations (437 μg/m and 572 μg/m, respectively) at the leeward sampling site are 12.5 and 4.6 times higher than the corresponding national standards of daily mean values (35 and 125 μg/m, respectively) during the beehive fireworks display. Closely examining PM accumulation fractions reveals that the accumulation mode particles dominate in the sized collected particles during the beehive fireworks display. Additionally, the K concentrations in PM1.0, PM2.5, and PM2.5–10 are 317, 349, and 249 times higher than those of its background value, while those of Cl are 91, 64, and 6.9 times greater than those of its background value. For ultrafine particles, the D/B (During the beehive fireworks display/Background) values of particlebound Cl, K, and Mg increase significantly during the beehive fireworks display at the leeward sampling site. Moreover, the maxima D/B value of K is 196 in the 0.1–0.18 m size range, revealing that the beehive firework aerosols are rich in Cl, K, and Mg ions.


INTRODUCTION
Short-term or instantaneous air pollution effects on health have received increasing attention in recent years, as evidenced by numerous efforts to characterize anthropogenic emissions, especially in urban areas where large populations live (Ravindra et al., 2003;Kulshrestha et al., 2004;Chang et al., 2013;You et al., 2013).The extensive use of pyrotechnics in large celebration events often significantly degrades shortterm air quality, possibly harming human health (Smith and Dinh, 1975;Clark, 1997;Gorbunov et al., 2013).An unusual source of atmospheric pollution) is the displacement of fireworks to celebrate festivities worldwide.
As is well known, ambient fine particle concentrations increase with fireworks displays (Vecchi et al., 2008).Fireworks burning may raise levels of particulate matters (Vecchi et al., 2008) containing water-soluble ions, metallic elements, and organic compounds (Liu et al., 1997;Ravindra et al., 2003;Kulshrestha et al., 2004;Drewnick et al., 2006;Moreno et al., 2007;Wang et al., 2007;Steinhauser et al., 2008).Zhang et al. (2010) found that particle concentrations during the peak hour of firework celebrations are approximately three times higher than the day before celebration, with a clear shift of particles from nuclei mode (10-20 nm) and Aitken mode (20-100 nm) to accumulation mode (0.5-1.0 µm).According to these studies (Wang et al., 2007;Chang et al., 2011;Huang et al., 2012;Tsai et al., 2012b), extensive burning of fireworks causes significant increases in the levels of PM 2.5 and PM 10 bound elements and water-soluble ions, as well as in the number concentration of particles in the size range of 100-500 nm.
Many studies have noted elevated concentrations of water-soluble ions (K + , Cl -, and SO 4 2-) in ambient aerosol particles during and shortly after fireworks displays (Ravindra et al., 2003;Drewnick et al., 2006;Moreno et al., 2007;Wang et al., 2007;Shen et al., 2009;Godri et al., 2010;Tsai et al., 2012a;Satsangi et al., 2013;You et al., 2013;Yang et al., 2014).However, the mass concentrations and chemical compositions (water-soluble ions components/ concentrations) of PM 0.1 , PM 1.0 , PM 2.5 , and PM 2.5-10 from beehive fireworks displays have seldom been studied.Therefore, this study investigates the mass concentrations in PM 0.1 , PM 1.0 , PM 2.5 and PM 2.5-10 , as well as determines the water-soluble ion components (Na + , K + , NH 4 + , Mg 2+ , Ca 2+ , Cl -, NO 3 -, and SO 4 2-)/concentrations in sized particles collected in the YanShuei area of southern Taiwan.The size distributions and cumulative mass fractions of particles/ water-soluble ions for each particle size range are based on the samples of particles collected by a MOUDI sampler.Analysis results demonstrate that a beehive fireworks display emits a significant amount of ultrafine particles instantaneously and degrades short-term air quality, thereby necessitating attention to address health concerns.

Collection of Particulates
Atmospheric particulate samples were collected in the YanShuei area of southern Taiwan during the Lantern Festival from February 21 to 25 in 2013.The windward sampling site was located on the roof of a three-story building (9 m height) in the Wumiao Temple, roughly 50 m north to the major beehive fireworks display site, while the leeward sampling site was located on the roof of a four-story building (12 m height) in the YanShuei police office, roughly 300 m south to the major beehive fireworks display site.The YanShuei beehive fireworks display events occurred within the four stages of our experimental periods.In this investigation, it is regarded that February 21 th -22 th , 23 th -24 th , 24 th (18:00-24:00), and 25 th 2013 were the before (background), trial, during, and after beehive fireworks display periods, respectively.The mean air temperature, relative humidity, and wind speed were 19.1 (14.4-26.4)°C,78.9 (56.0-94.0)%,and 0.54 (0.0-2.2) m/s, respectively, during the sampling period (without any rain).
Silicon grease was applied to the surface of each filter installed in the MOUDI sampler, and the greased filterstrips were baked in a 60°C oven for 90 min to stabilize the silicon grease before sampling to minimize particle bounce between the different stages of the MOUDI during the sampling.Before and after each sampling, the filters were dried for 24 h in a desiccator at 25°C in 40% relative humidity.They were then weighed on an electronic balance (AND HM202) with a resolution of 10 µg.The suspended particulate matter concentration was determined by dividing the particle mass by the volume of sampled air.

Water-Soluble Ion Analysis and Quality Control
Before the property of the particle-bound water-soluble inorganic species (Na + , K + , NH 4 + , Mg 2+ , Ca 2+ , Cl -, NO 3 -, and SO 4 2-) were determined quantitatively, collected particles from each Teflon fiber filter had been extracted using 10 mL of ultra-pure water (specific resistance 18.3 MΩcm).The water-soluble ions were extracted using an ultrasonic bath (UC-300) for 120 minutes.All extraction solutions were filtered through a cellulose acetate filter (ADVANTEC MFS, Inc., USA cat No., CO20A025A; pore size of 0.2 µm; diameter of 25 mm) and stored in plastic vials in a refrigerator at 4°C until they were chemically analyzed.The inorganic species were analyzed by ion chromatography (IC) (DIONEX ICS-3000 with conductivity detection (DC detector/chromatography module, P/N 061767)).The cations were identified using a DIONEX IonPac® 4 × 50 mm CG12A guard column, a DIONEX IonPac® 4 × 250 mm CS12A analytical column, and a cation self-regenerating suppressor (CSRS® ULTRA II, 4 mm, AutoSuppression® Recycle Mode); the anions were identified using a DIONEX IonPac® 4 × 50 mm AG11 guard column, a DIONEX IonPac® 4 × 250 mm AS11 analytical column, and an anion self-regenerating suppressor (ASRS® ULTRA II, 4 mm, AutoSuppression® Recycle Mode).The eluents for the cation and anion analyses were 20 mM of methane sulfonic acid and 12 mM of NaOH, respectively.Analytical drift was monitored throughout the analytical procedures.Next, recovery efficiencies were determined using diluted samples that were spiked with known quantities of the ions of interest.Recovery efficiencies ranged from 93% to 107%.The method detection limit (MDL) was estimated by repeatedly analyzing a control solution of known quality.Replicate analysis of IC measurements was performed to calculate the MDL of each element using MDL = 2.681 × S pooled , with S A 2 /S B 2 < 3.05.S pooled = [(6S A 2 + 6S B 2 )/12] 0.5 , where S pooled denotes the pooled standard deviation; S A represents the standard deviation of property of the prepared sample with a larger F-test value, and S B is the standard deviation of the other sample.The detection limits in ng/m 3 (estimated from MDL × volume of analyte solution (10 mL)/average sampling volume (20 m 3 )) were Na + , 7.00 ng/m 3 ; K + , 12.0 ng/m 3 ; NH 4 + , 27.0 ng/m 3 ; Mg 2+ , 13.0 ng/m 3 ; Ca 2+ , 10.5 ng/m 3 ; Cl -, 46.6 ng/m 3 ; NO 3 -, 28.6 ng/m 3 ; and SO 4 2-, 61.6 ng/m 3 .Both field and laboratory blank samples were prepared and analyzed for each sampling and analysis.All data were corrected with blanks.

Atmospheric Particle Concentrations and Mass Size Distributions
Table 1 lists the concentrations of particles before (background), trial, during, and after a beehive fireworks display in the 2013 YanShuei Fireworks Festival on the rooftop of the Wumiao Temple (windward) and YanShuei police office (leeward).At the windward sampling site, the PM 0.1 , PM 1.0 , PM 2.5 , and PM 2.5-10 concentrations were 0.767, 17.4, 26.1, and 19.3 µg/m 3 , respectively, before beehive fireworks display (background).Corresponding data were 2. 48, 30.6, 46.1, and 39.3After the display, the values were 1.36, 45.7, 103, and 45.0 µg/m 3 , respectively.On the other site (leeward), the PM 0.1 / PM 1.0 /PM 2.5 /PM 2.5-10 concentrations were 1.73/20.9/28.2/12.4,9.86/77.9/120/61.0,2.73/321/437/135, and 1.36/45.7/103/45.0µg/m 3 , at the before, trial, during, and after the beehive fireworks display, respectively.PM 2.5 concentrations greater than 437 µg/m 3 during the beehive fireworks may cause adversely impact the health of susceptible individuals.However, these adverse effects are limited, owing to the short exposure to the peak concentrations.Yang et al. (2014) found higher PM 2.5 concentrations (maximum = 464.02µg/m 3 ) during the 2008 Chinese New Year period than in previous years.High PM 2.5 concentrations were also observed (range = 117-217 µg/m 3 ; average = 183 µg/m 3 , i.e. roughly six times higher than those before and after the Chinese New Year) in the Yellow River Delta region during the Chinese New Year in 2011 (Li et al., 2013).Before the YanShui beehive fireworks display, the PM 2.5 concentrations were 26.1 and 28.2 µg/m 3 , respectively, at the windward and leeward sampling sites, while the PM 10 ones were 45.4 and 40.6 µg/m 3 , respectively.Notably, the PM 2.5 and PM 10 concentrations of air quality standards in Taiwan are 35 and 125 µg/m 3 , respectively.At the windward and leeward sampling sites, the PM 2.5 /PM 10 ratios were 0.57 and 0.69, respectively.Moreover, the PM 2.5 concentration significantly increased during the YanShui beehive fireworks display, and the PM 2.5 /PM 10 ratios) obviously increased to 0.74 and 0.76 at the windward and leeward, respectively.Tsai et al. (2012b) indicated that the PM 2.5 /PM 10 ratios observed during the fireworks display periods ranged from 0.61 to 0.73 with an average of 0.69.In the center of Mainz, a small city in central Germany (population 120,000), the average total mass concentration measured by a timeof-flight aerosol mass spectrometer (TOF-AMS) for the entire day of January 1 was 51.0 µg/m 3 (Drewnick et al., 2006).Shen et al. (2009) sampled PM 2.5 for 24 hours in XiAn using Dichot samplers during the fireworks display during the Chinese New Year.According to their results, the average PM 2.5 concentration was 300 µg/m 3 , i.e., 3-4 times higher than the regular value obtained when no fireworks were displayed.
At the leeward site, the PM 0.1 concentration after the fireworks display was 1.67 µg/m 3 , i.e., lower than the background value (1.73 µg/m 3 ).Whereas the value was 9.86 µg/m 3 during the trial stage, i.e., higher than that (2.73 µg/m 3 ) during the beehive fireworks display.During the 4 periods of the beehive fireworks display, the PM 1.0 , PM 2.5 , and PM 2.5-10 concentrations were the highest during the beehive fireworks display and the lowest before the beehive fireworks display (background values).During the four periods (before (background), trial, during, and after) of the beehive fireworks display, the concentrations of sized PMs were lower at the windward site than those at the leeward one, except that of PM 0.1 during beehive fireworks display and that of background PM 2.5-10 .This finding suggests that festival attendees on the leeward of beehive fireworks displaying area had a greater risk of high concentration PM exposure than those at the windward site.

Particle Mass Size Distributions and Accumulation Fractions
Particle mass size distributions at YanShui before (background), trial, during, and after the beehive fireworks display were all bi-modal distribution with one main peak in the fine size range and the other in the coarse size domain (Figs.1-3).At both of the windward and leeward sampling sites, the major peaks of particle mass size distributions were in the accumulation mode (0.56-1.0 µm) during the beehive fireworks display; however, they were in the drop mode (1.0-1.8 µm) after the display.Yang et al. (2014) indicated that the widespread burning of fireworks during the 2008 Chinese New Year obviously contributed to the number concentration of small accumulation mode particles (100-500 nm).
At the windward sampling site, the background accumulation fractions of PM 0.1 , PM 1 , and PM 2.5 were 4.1, 47.7, and 64.3%, respectively; 5.2, 41.4, and 63.9%, respectively, during the trial display stage; 0.4, 52.9, and 71.8%, respectively, during the beehive fireworks display period; and 1.0, 25.2, and 62.1%, respectively, after the display (Fig. 4).At the leeward sampling site, the corresponding values were 1.6, 35.5, and 53.3%, respectively, for the background period; 2.6, 32.2, and 48.5%, respectively, during the trial display stage; 4.7, 50.3, and 68.9%, respectively, during the beehive fireworks display period; and 0.9, 29.9, and 67.6%, respectively, after the display (Fig. 5).Above results indicate that most of the particles produced during the beehive fireworks display were in the accumulation mode.Yang et al. (2014) found that dominated in size fractions, Aitken and accumulation mode particles accounting for 57% and 42%, respectively, of the total particle number concentration during the 2008 Chinese New Year period.At both sampling sites, the mean accumulation fractions of PM 1 during the beehive fireworks display period approximately increased by 10 to 18% over those during the trial display period.Meanwhile, the corresponding values during the beehive fireworks display period were approximately 2.0 times those after the display.Above results imply that the beehive fireworks display affected the size distribution of local atmospheric particles, which may be associated with the growth of Aitken-mode aerosols and their transformation into fine-mode ones by condensation, coagulation, aggregation, and aging during the transport.

Impact of Firework/Fireworks Display on Airborne Particles
Table 2 displays the concentration ratios of sized particles collected during the four sampling periods at the Wumiao temple (windward) and the YanShuei police office (leeward).
During the trial fireworks display period, the PM 0.1 , PM 1.0 , PM 2.5 , and PM 2.5-10 concentrations were 3.2, 1.8, 1.8, 2.0 times higher than the background values, respectively, at the windward sampling site; meanwhile, those at the leeward sampling site were 5.7, 3.7, 4.3, and 4.9 times greater than the background ones.During the beehive fireworks display period, the corresponding times were 14.7, 6.9, 6.3, and 3.0, respectively, at windward, and 1.6, 15.4, 15.5, and 10.9, respectively, at leeward.After the fireworks display, the PM 0.1 , PM 1.0 , PM 2.5 , and PM 2.5-10 concentrations at windward were still (1.8, 2.6, 3.9, and 2.3 times, respectively) higher than the background data; this was also true for those of PM 1.0 , PM 2.5 , and PM 2.5-10 at leeward (2.1, 3.8, and 4.5 times, respectively).However, the PM 0.1 concentration (1.67 µg/m 3 ) was close to that of the background value (1.73 µg/m 3 ).The background PM 2.5 and PM 10 concentrations at windward were 26.1 and 45.4 µg/m 3 , respectively, and those at leeward were lower (28.2 and 40.6 µg/m 3 , respectively), thereby complying with the national air quality standards (35 and 125 µg/m 3 , respectively).During the beehive fireworks display, the PM 1.0 concentrations at the windward and leeward sampling sites were 120 and 321 µg/m 3 , respectively, which were 6.9 and 15.4 times higher than the background values.Moreover, the PM 2.5 and PM 10 concentrations also exceeded the national standards.At the windward sampling site, the PM 2.5 and PM 10 concentrations were 165 µg/m 3 and 222 µg/m 3 , respectively, i.e., approximately 4.7 and 4.9 times higher than the background values, respectively, whereas at leeward those of PM 2.5 and PM 10 (437 µg/m 3 and 572 µg/m 3 , respectively) were 12.5 and 4.6 times greater than the national standards (35 and 125 µg/m 3 , respectively).
According to a related study on how firecrackers and fireworks display during the 2014 Chinese New Year affect ambient fine particles, the mass concentration of PM 2.5 reached ~464 µg/m 3 during the firecracker display, i.e., around four times higher than the average value (114 µg/m 3 ) of the non-firecracker period (Yang et al., 2014).Correspondingly, Barman et al. (2008) also observed that the PM 10 concentration in Diwali was ~1206 µg/m 3 , which was 4 times higher than that without fireworks display.

Effect of Firework Displays on Ambient Particles Size Distribution
According to Kulmala et al. (2004), atmospheric particles can be divided into three size groups: Aitken nuclei mode (dp ≤ 0.1 µm, PM 0.1 ), accumulation mode (0.1 < dp ≤ 1.0 µm, PM 0.1-1.0 ), and coarse mode (dp > 1.0 µm: 1.0 < dp ≤ 2.5 µm and 2.5 < dp ≤ 10 µm two size ranges).Table 3 shows the accumulation fractions of particles in these size ranges.About half of the PM 10 concentrations were in the Aitken nuclei (PM 0.  ) and 49% (18% + 31%) at the windward and leeward sites, respectively.During the fireworks display, the Accumulation mode PM (submicron particles easily entering the human respiratory system (alveolar region)) increased the most in accumulation fraction percentage among the three mode PMs.The percentage of PM 10 in Accumulation mode increased by ~12% (= 49% -36.6%) at the windward site; the increase was ~9% (= 55.6% -47.2%).

Contrast between Concentrations of Particles with Various Diameters at the Two Sampling Sites
At the leeward sampling site, the PM 0.1 /PM 2.5 values resembled each other before and after beehive fireworks display (Fig. 6); those at both sampling sites (0.73 and 0.74, respectively) also resembled each other (Figs.6 and   7).Also, the PM 0.1 /PM 2.5 value during the beehive fireworks display was higher than those of trial and after display periods, probably due to the significant increase of accumulation mode of PM 2.5 .The lower ratios (0.44 and 0.41 at leeward and windward, respectively) after beehive fireworks display originated from the larger increase of PM 1.0-2.5 in PM 2.5 , as shown in Table 1.The ratios of PM 0.1 /PM 2.5 (ultrafine to fine particles) before and after the display at the four sampling periods at both sites ranged from 0.01 to 0.08 (average = 0.04).Similar individual PM 0.1 /PM 2.5 ranges (and averages) were obtained at both sites.However, the increase (by 6.25%) of ultrafine particle concentration in PM 2.5 at the windward site during beehive fireworks display should be of concern in terms of its adverse effect on human health.

Concentrations of Particulate Water-Soluble Ions with Various Particle Diameters before and after the Display
Tables 4 and 5  PM 1.0 , PM 2.5 , and PM 2.5-10 at the windward and leeward sampling sites, respectively.These tables reveal that, except for Ca 2+ in PM 1.0 at the leeward site, the concentrations of the other eight ions in PM 1.0 and PM 2.5 sampled at both sites during the fireworks display were higher than the background value.Among the tested ions, K + exhibited the highest increase in concentration owing to the fireworks display; the concentrations of K + in both PM 1.0 and PM 2.5 at the leeward site were 317 and 349 times higher than those of background values, respectively.Mg 2+ had the second (112 and 66 times higher, respectively) and Cl -showed the third (91 and 64 times higher, respectively) highest increase in concentration.The significant increases of these three ions in PM are likely owing to the KNO 3 , KClO 4 , KClO 3 , K 2 Cr 2 O 4 , and K 2 Cr 2 O 7 (used as oxidants) in fireworks.
During and after the fireworks display, the concentrations of the eight ions in PM 2.5-10 at the leeward site were also higher than their corresponding background values.In particular, during the beehive fireworks display, the concentration of K + in PM 2.5-10 was 7.22 µg/m 3 , approximately 249 times than its background value (0.029 µg/m 3 ).The fireworks are composed mainly of KNO 3 , KClO 4 , KClO 3 , K 2 Cr 2 O 4 , K 2 Cr 2 O 7 , carbon dust, and sulfur.When the fireworks were ignited, potassium nitrate was catalyzed and then helped to produce CO 2 , leading to increases in the instantaneous pressure and pushes of firework rockets in the air and, finally, their explosion.After the explosion, the ashes contained not only NO 3 -and SO 4 2-, but also K + and Cl -, which were detected at the leeward sampling site.According to our results, the concentrations of K + and Cl -in PM 1.0 , PM 2.5 , and PM 2.5-10 significantly increased, which were markedly higher than their background values during the intensive display of beehive fireworks.The concentrations of K + in PM 1.0 , PM 2.5 , and PM 2.5-10 were 317, 349, and 249 times higher than their background values; meanwhile, those of Cl -were 91, 64, and 6.9 times greater than their background values.Large amounts of K-rich particles observed in this study are consistent with those found in some previous investigations in urban areas during firework periods (Drewnick et al., 2006;Moreno et al., 2007;Wang et al., 2007;Joly et al., 2010).Wilkin et al. (2007) and Shi et al. (2011) found a high perchlorate content in the particles in urban cites after firecracker/firework activity.Kulshrestha et al. (2004) also found that K increased the most in concentration in PM (i.e., 25 times higher than those of regular days) during the display of firecrackers and fireworks in Diwali in India.

Variation in the Concentrations of Water-Soluble Ions in PM with Various Diameters before and after the Display
At the windward side, the masses of secondary aerosol (including NH 4 + , NO 3 -, and SO 4 2-in PM 1.0 , PM 2.5 , and PM 2.5-10 ) were the lowest at four sampling periods before and after the beehive fireworks display (Tables 4 and 5).The contents of secondary aerosol in PM 2.5 and PM 2.5-10 increased with the total amount of displayed beehive fireworks.Conversely, at the leeward site, the contents of secondary aerosol in PM 1.0 , PM 2.5 , and PM 2.5-10 were higher than their background values.Although secondary aerosols (NH 4 + , NO 3 -, and SO 4 2-) were produced as fireworks displayed, incomplete combustion of fireworks (e.g., present as OC and EC) might occur in a fireworks explosion.The significant amount of incomplete combustion products from the explosion could markedly increase the carbon content in the sized PMs, resulting in their higher concentrations (compared with background values) in secondary aerosol in PMs (Tables 4 and 5).However, the amounts of secondary aerosols in PMs were lower than background ones.
At the windward sampling site, during the beehive fireworks display, the concentrations of K + in PM 1.0 , PM 2.5 , and PM 2.5-10 were 1.95, 2.33, and 0.359 µg/m 3 , respectively, greater than the background values (0.597, 0.751, and 0.261 µg/m 3 , respectively) (Table 4).The content percentages of K + in PM 1.0 , PM 2.5 , and PM 2.5-10 were 1.6, 2.33, and 0.6%, respectively.These contents were relatively lower than the background values (3.4%, 2.9%, and 1.1%, respectively).The concentrations of Cl -in PM 1.0 and PM 2.5 during beehive fireworks display were 1.64 and 2.21 µg/m 3 , respectively, which were 7.1 and 5.1 times the background values (0.232 and 0.435 µg/m 3 , respectively).However, Cl -accounts for 1.4% in PM 1.0 , close to its background value (1.3%).Meanwhile, that for the value was 1.3% in PM 2.5 , lower than its background value (1.7%).Additionally, the increase in measured Cl -concentration suggests that KClO 3 and KClO 4 are used as the major oxygen sources in the firecrackers.Table 4 reveals that the concentrations of both K + and Cl -in PM 1.0 , PM 2.5 , and PM 2.5-10 at the windward side are higher than the background ones.In contrast to the results obtained at the windward sampling site, the amounts of K + and Cl -in PM 1.0 , PM 2.5 , and PM 2.5-10 at the leeward sampling site were the highest (17.8%, 14.9%, and 7.5%, respectively) during the intensive beehive fireworks display; they were 11, 9.3, and 2.1 times higher than their background values (1.6%, 1.6%, and 3.6%).
Obviously, the concentrations of Mg 2+ in PM 2.5 and PM 2.5-10 increase at the leeward sampling site (Table 6).The Mg 2+ concentrations in PM 2.5 sampled during and after the display were 2.98 and 0.322 µg/m 3 , respectively; they were 66 and 7.2 times higher than the background value (0.045 µg/m 3 ), respectively; those in PM 2.5-10 were 0.773 and 0.590 µg/m 3 , respectively, 20 and 16 times higher the background value of 0.038 µg/m 3 , respectively.This finding is associated with the fact that fireworks usually consist of various compositions, including Mg and Al compounds (for displaying white flames).Moreno et al. (2007) studied how the fireworks displays at festivals in Spain affect the particulate matter.According to their results, the concentrations of K, Al, and Mg range from 0.5-5.9,0.6-2.2, and 0.1-0.5 µg/m 3 , respectively.A study by Wang et al. ( 2007) on the Lantern Festival in Beijing, China demonstrated that in PM 2.5 and PM 10 , K + (21 times), Mg 2+ (11 times), and Cl -(9 times) ranked as the third largest increase in the amount of all water-soluble ions.

Ratios (T/B, D/B, and A/B) (Ratios of Values of before (Background (B)), Trail (T), During (D), and After (A) Beehive Firework Display Periods) of Particle-Bound Water-Soluble ion Compositions for Different PMs
According to Fig. 8, the D/B values of particle-bound Cl -, K + , and Mg 2+ ions significantly increased in ultrafine particle during the beehive fireworks display at the leeward sampling site.The maxima D/B value of K + is 196 in the 0.1-0.18µm size range.However, the D/B values of particlebound secondary aerosol species were nearly smaller than T/B and A/B data.(Notably, the ratios of ion compositions were from 0 to 2.) This finding suggests that the particlebound Cl -, K + , and Mg 2+ increased during the beehive fireworks display, thus demonstrating that firework aerosols are rich in Cl -, K + , and Mg 2+ ions.

CONCLUSIONS
This study investigates water-soluble ions in the sized particles collected using a MOUDI sampler in the YanShuei area of southern Taiwan during a beehive fireworks display.The results indicate that PM 2.5 concentrations greater than 437 µg/m 3 during the beehive fireworks may cause adversely impact the health of susceptible individuals.Particle mass size distributions at YanShui before (background), trial, during, and after the beehive fireworks display were all bimodal distribution with one main peak in the fine size range and the other in the coarse size domain and most of the particles produced during the beehive fireworks display were in the accumulation mode.At the windward sampling site, the PM 2.5 and PM 10 concentrations were approximately 4.7 and 4.9 times higher than the background values, respectively, whereas at leeward those of PM 2.5 and PM 10 were 12.5 and 4.6 times greater than the national standards (35 and 125 µg/m 3 , respectively).Among the tested ions, K + exhibited the highest increase in concentration owing to the fireworks display; the concentrations of K + in both PM 1.0 and PM 2.5 at the leeward site were 317 and 349 times higher than those of background values, respectively.Mg 2+ had the second (112 and 66 times higher, respectively) and Cl -showed the third (91 and 64 times higher, respectively) highest increase in concentration.This finding suggests that the particle-bound Cl -, K + , and Mg 2+ increased during the beehive fireworks display, thus demonstrating that firework aerosols are rich in Cl -, K + , and Mg 2+ ions.Lin et al., Aerosol andAir Quality Research, 14: 1998-2009

Fig. 5 .
Fig. 5. Cumulative mass fractions of the particles collected of before (background), trial, during, and after beehive fireworks display periods at the windward.

Fig. 8 .
Fig. 8. T/B, D/B, and A/B values and ratios of ion compositions of particle-bound water-soluble ions in different particle size ranges at the leeward sampling sites.

Table 1 .
PM concentrations and PM 2.5 /PM 10 values at the four periods (before (background), trial, during, and after) of a beehive fireworks display.

Table 2
. T/B, D/B, and A/B values of before (background (B)), trail (T), during (D), and after (A) beehive fireworks display periods.

Table 3 .
Accumulation fractions (%) of PMs with dp sizes in different modes (Aitken nuclei, accumulation, and coarse modes).

Table 4 .
Concentrations of water-soluble ions in PM 1.0 , PM 2.5 , and PM 2.5-10 at the windward sampling site.

Table 5 .
Concentrations of water-soluble ions in PM 1.0 , PM 2.5 , and PM 2.5-10 of four sampling periods at the leeward sampling site.

Table 6 .
D/B and A/B values of for PM 1.0 , PM 2.5 , and PM 2.5-10 during the beehive fireworks display.