3.2. Fraction of soluble iodine and distribution between coarse
and fine aerosol
TSI/TI average, minimum and maximum ratios in bulk aerosol for different
campaigns are listed in Table S3. Figure 2 shows TSI/TI statistics as a
function of latitude for 10° zonal bins. These data were already used in
our previous publication to scale TSI measurements to TI estimates
(Gómez Martín et al., 2021), and therefore will be only briefly
discussed. Concurrent TI and TSI observations are available from only
eight campaigns (fist row in Table 1), while size segregated
measurements of both TI and TSI are only available for campaign C12. In
the bulk aerosol, an average of 65-80% of TI is in soluble form (Figure
2). The average TSI/TI ratio is 66%, while the TSI fraction derived
from the slope of a TI vs TSI error-weighted fit is 79% (Gómez Martín
et al., 2021). Seven TSI/TI ratios (four in C7 and three in C12) are
larger than 1 beyond 2σ analytical uncertainty and have been excluded
from the soluble fraction statistical analysis, since TI = TSI + NSI ≥
TSI must be fulfilled.