Ch3coch3 O

Sabinene

Terpinolene

" Adapted from Atkinson (1997a). 6 Hakola et al. (1994). ' Hakola et al. (1993).

'' Hatakeyama et al. (1991); yields may be too high due to contribution from other products to IR absorption.

' Grosjean et al. (1993a). ' Aschmann et al. (1998). s Alvarado et al. (1998b).

noon, likely reflecting their simultaneous removal by reaction with OH and/or photolysis.

The atmospheric oxidation of biogenic hydrocarbons appears to be a significant source of CO on a global level, accounting for ~ 10-20% of the total (e.g., Hatakeyama et al., 1991; Miyoshi et al., 1994; Rockmann et al., 1998).

Nighttime reactions of biogenics with NO-, are also important. As seen in Table 6.13, many of these reactions are very fast, leading to relatively short lifetimes of the biogenics at night. For a-pinene, for example, the lifetime with respect to reaction with 50 ppt N03 is only ~2 min. Again the reactions produce a number of multifunctional products, in this case many of them containing the nitrate group. For example, Wangberg et al. (1997) found total organic nitrate yields of about 14% in the N03-a-pinene reaction, which included 3-oxopinane 2-nitrate (3% yield) and 2-hydroxypinane 3-nitrate (5% yield), as well as the major product pinonaldehyde (62% yield):

Pinonaldehyde o

3-Oxopinane 2-nitrate

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