Chemistry of NPF in mixed biogenic and urban emissions - Observations from CARES

Q. Zhang, A. Setyan, et al

UC Davis

T0

T1

Frequent NPF & growth events • Occurred on regional scale,

T0 data from C. Song

• new particles were transported from T0 to T1

• PM grow during transport

Frequent NPF & growth events

4

Τ1 ∆Dm/∆t ~ 5 nm / hr T0 ∆Dm/∆t ~ 7 nm / hr

Interrogate the chemistry of NP growth Growth driven by condensation of organics and sulfate

NPF days Non-NPF days

Growth of New Particles: SOA >> Sulfate

Urban transport, “A”-SOA

Biogenic influenced, “B”-SOA

Growth of New Particles: SOA >> Sulfate

a)

b)

Growth of new particles was mainly driven by “A”-influenced SOA

c)

d)

Urban transport, “A”-SOA

Biogenic influenced, “B”-SOA

T0

T1

Refineries (SO2)

Night time Day time

Setyan et al., ACP, 2012