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. 2020 Jul 4;742:140739. doi: 10.1016/j.scitotenv.2020.140739

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Fig. 5 — 6-Day running averages of (a) Org/PM, (b) SO₄/PM, (c) NO₃/PM, (d) SOA/OA, (e) POA/OA, (f) BC/PM for each year during 2012–2020. The shaded areas indicate the 7-day CNY period, and the x-axis indicates the days from the first day of CNY holiday.