“…For example, some field studies have shown that a 1 μg/m 3 decrease in sulfate can lead to a 0.2–0.42 μg/m 3 decrease in isoprene SOA (Blanchard et al, ; Budisulistiorini et al, ; Pye et al, ; Shrivastava et al, ; Xu et al, , ). Similarly, decreases in NO x have been shown to decrease biogenic SOA formation but there are also studies that have shown increases of biogenic SOA in some regimes with decreased NO x (Table ; de Sa et al, ; Edwards et al, ; Kroll et al, ; Lane et al, ; Liu et al, ; Matsui et al, ; Ng et al, ; Pye et al, , , ; Rollins et al, ; Wildt et al, ; Xu et al, , ; Zhang et al, ; Zheng et al, ). Since these effects of NO x have been shown by laboratory studies to affect biogenic SOA formation by changing oxidation pathways and ultimate products (Atkinson et al, ; Hoyle et al, ; Kroll et al, ; Presto et al, ; Shrivastava et al, ; Surratt et al, ; Ziemann & Atkinson, ), it is important to quantify them in atmospheric field studies.…”