Characteristics of particulate constituents and gas precursors during the episode and non-episode periods

Figures & data

Figure 1. Map of sampling site.

Table 1 . PM mass concentration at different particle sizes on episode and non-episode days

	Episode days		Non-episode days
PM concentration (μg m^−3)	Daytime (n = 15)	Nighttime (n = 15)	Daytime (n = 18)	Nighttime (n = 17)
TSP	133 ± 32 (101–206)	162 ± 26 (125–204)	59 ± 32 (12–112)	66 ± 34 (18–112)
PM10	101 ± 27 (72−161)	133 ± 23 (104–173)	47 ± 27 (7.8–95)	52 ± 29 (12–90)
PM2.5	76 ± 21 (50–123)	106 ± 19 (80–137)	37 ± 28 (4.6–80)	40 ± 24 (7.6–70)
PM1	57 ± 19 (39–100)	64 ± 11 (42–75)	28 ± 18 (3.4–57)	27 ± 16 (5.4–52)
PM0.1	5.9 ± 4.1 (1.4–15)	3.7 ± 1.0 (2.8–5.5)	4.04 ± 4.3 (0.28–15)	3.3 ± 3.7 (0.38–11)
Note: Numbers in parentheses are the range of concentration.

Figure 2. PM mass concentration distribution of different size segregation.

Table 2 . Meteorological parameter during the sampling periods

	Episode days		Non-episode days
Parameters	Daytime (n = 15)	Nighttime (n = 15)	Daytime (n = 18)	Nighttime (n = 17)
Temperature (°C)		21.2 ± 1.9 (16.9–23.2)	28.6 ± 3.2 (22.3–32.9)	25.5 ± 4.6 (16.9–29.2)
Relative humidity (%)	60.9 ± 5.1 (48.9–65.2)	75.5 ± 4.1 (68.7–81.40)	59.2 ± 9.2 (36.9–71.7)	77.2 ± 5.2 (67.4–82.6)
Wind speed (m/sec)	1.8 ± 0.5 (1.1–3.2)	1.3 ± 0.5 (0.8–2.3)	2.1 ± 0.7 (1.4–3.8)	1.0 ± 0.5 (0.4–2.0)

Figure 3. PM mass concentrations with the distribution of temperatures.

Figure 4. PM mass concentration distribution at different wind directions in winter and summer.

Figure 5. Distribution of inorganic ions in different PM sizes during the day and at night during non-episode periods.

Figure 6. Distribution of inorganic ions in different PM size during the day and at night during episode periods.

Table 3 . Concentration (μg m^{− 3}) of acid and base gases on episode and non-episode days

	Episode		Non-episode
Gas species	Day (n = 15)	Night (n = 15)	Day (n = 18)	Night (n = 17)	New York, NY (Bari et al., 2003) at 1 atm, 25°C	Taichung, Taiwan (Lin et al, 2006)
HNO2	4.20 ± 1.0 (2.60–5.40)	7.74 ± 2.7 (4.13–12.54)	3.14 ± 1.5 (1.38–7.23)	4.07 ± 2.3 (0.74–7.21)	3.23 (0.04–16.8)	2.9 ± 1.4 (1.1–7.7)
HNO3	6.83 ± 2.4 (4.17–10.3)	0.82 ± 0.4 (0.26–1.54)	3.70 ± 1.8 (1.71–6.28)	0.46 ± 0.3 (0.09–0.91)	1.30 (0.03–14.7)	1.9 ± 1.1 (0.4–5.3)
HCl	3.25 ± 2.7 (0.63–9.92)	1.18 ± 1.0 (0.17–2.81)	4.65 ± 2.9 (0.65–9.35)	0.44 ± 0.2 (0.05–0.72)	0.45 (0.01–3.0)	NA
NH3	22.70 ± 7.5 (13.3–36.5)	40.08 ± 15.5 (13.9–70.6)	19.69 ± 9.6 (7.28–39.4)	43.91 ± 10.0 (28.6–56.6)	2.82 (0.07–10.8)	8.5 ± 3.0 (2.1–14.4)
SO2	30.43 ± 9.9 (16.4–43.1)	15.02 ± 7.7 (4.64–27.5)	14.78 ± 10.6 (1.91–33.2)	10.23 ± 9.7 (0.76–26.2)	26.5 (1.6–157)	NA
Note: Numbers in parenthesis present the range of concentration. NA: not available.

Figure 7. Relationships of inorganic ions in particulate matter.

Bari , A. , Ferraro , V. , Wilson , L.R. , Luttinger , D. and Husain , L. 2003 . Measurements of gaseous HONO, HNO3, SO2, HCl, NH3, particulate sulfate and PM2.5 in New York, NY . Atmospheric Environment , 37 : 2825 – 2835 . doi: 10.1016/S1352-2310(03)00199-7

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Lin , Y.C. , Cheng , M.T. , Ting , W.Y. and Yeh , C.R. 2006 . Characteristics of gaseous HNO2, HNO3, NH3 and particulate ammonium nitrate in an urban city of Central Taiwan . Atmospheric Environment , 40 : 4725 – 4733 . doi: 10.1016/j.atmosenv.2006.04.037

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