The Impact of Nonlocal Ammonia on Submicron Particulate Matter and Visibility Degradation in Urban Shanghai

Table 3

Average values for the molar equivalent ratio of ammonium to the sum of sulfate and nitrate (1), [NH₄⁺]_PRED, [NH₄⁺]_MEAS, and the difference between the latter two during the haze, foggy, and clear weather periods.

Start and end time	Equation (1)	NH4^+PRED	NH4^+MEAS	NH4^+MEAS − NH4^+PRED
		(μg/m^3)	(μg/m^3)	(μg/m^3)
(1) 3/12 12.00–3/12 21.00	1.06 ± 0.04	6.1	6.4	0.3
(2) 7/12 22.00–9/12 01.00	1.13 ± 0.08	9.7	11.0	1.3
(3) 14/12 12.00–15/12 00.00	1.21 ± 0.04	6.8	8.2	1.4
(4) 16/12 15.00–17/12 07.00	1.07 ± 0.04	4.6	4.9	0.3
(5) 21/12 09.00–21/12 18.00	1.15 ± 0.04	4.0	4.6	0.6
(6) 22/12 09.00–22/12 14.00	1.01 ± 0.02	7.8	7.9	0.1
(7) 23/12 07.00–23/12 16.00	1.03 ± 0.05	9.0	9.3	0.3
(8) 29/12 23.00–30/12 06.00	1.02 ± 0.03	5.4	5.5	0.1
Ave. “haze periods” (94 hours)	1.10 ± 0.08	7.2	7.9	0.7
Ave. “foggy” periods (40 hours)	1.07 ± 0.08	2.7	2.9	0.2
Ave. “clear” periods (483 hours)	1.05 ± 0.11	3.7	3.9	0.2