Table 3. Molar Ratio of Oxalate Relative to Sulfate, Nitrate, and Ammoniuma 			
Atmospheric Condition Type and Inlet (Number of Vials With Oxalate Above Detection Limits/Total Number of Vials)	SO42- Slope (R2)	NO3- Slope (R2)	NH4+ Slope (R2)
Clouds uninfluenced by local pollution sources			
CVI (34/131)	0.014 (0.37)	0.010 (0.15)	0.006 (0.24)
Main (54/92)	0.024 (0.75)	 -0.007 (0.01)	0.015 (0.59)
Cumulative (88/223)	0.023 (0.71)	0.000 (0.00)	0.013 (0.55)
Power plant plume in cloud			
CVI (11/32) 	0.083 (0.97)	 -0.009 (0.00)	0.073 (0.45)
Main (44/79) 	0.028 (0.77)	 -0.110 (0.03)	0.026 (0.81)
Cumulative (55/111)	0.028 (0.82)	 -0.031 (0.04)	0.026 (0.84)
Cloud-free air			
Main (24/196)	0.000 (0.00)	0.010 (0.08)	0.002 (0.17)
Power plant plume in cloud-free air			
Main (10/24)	0.015 (0.21)	0.011 (0.10)	0.011 (0.28)
Power plant plume in cloud-free air with precipitation from scattered clouds overhead			
Main (18/21)	0.051 (0.56)	0.031 (0.09)	0.024 (0.52)
aCVI samples correspond to cloud droplet residual particles; main inlet samples correspond to total aerosol, which includes a mixture of interstitial aerosol and droplet residuals in clouds.