Characterizations of Particle Size Distribution of the Droplets
Exhaled by Sneeze
Z.Y. Han, W.G. Weng, Q.Y. Huang
Supplementary Material
1 Time stability of the sneeze droplet size distribution.
In this experiment, the sampling frequency was set as 2.5 kHz. The size distribution of the spray
would be measured and recorded every 0.4ms. And so the time stability of the droplet size
distribution for each sneeze is also studied. Figs. S1 and S2 demonstrate the size distribution of
sneeze droplets measured at 100ms, 200ms, 300ms, 400ms, 500ms and 600ms after the sneeze
begin, for unimodal and bimodal distributions respectively. As shown in Figs. S1 and S2, the
volume-based size distribution measured at different time during a sneeze is similar, both for
unimodal and bimodal distributions. This result proves that the distribution characteristic of
sneeze droplets will remain almost the same in the duration of the sneeze, both for unimodal and
bimodal distributions.
Fig. S1 Volume-based size distribution measured at different time in the duration of one sneeze
(unimodal distribution).
Fig. S2 Volume-based size distribution measured at different time in the duration of one sneeze
(bimodal distribution).
2 Average number size distribution of sneeze droplets
According to the calculation method proposed in this work, the number size distribution of the
droplets of all the forty-four sneezes can be calculated, both for unimodal and bimodal
distributions. The average number size distribution can be calculated for the two types of
distributions, respectively. Detailed information of the calculated average number size distribution
is given in Table S1 and S2.
Table S1. The average number size distribution of the unimodal size distribution
Size class (μm)
Quantity Proportion (averaged per person)
Standard deviation
<100
100.0~116.6
116.6~135.9
135.9~158.5
158.5~184.8
184.8~215.4
215.4~251.2
251.2~292.9
292.9~341.5
341.5~398.1
398.1~464.2
464.2~541.2
541.2~631.0
631.0~735.6
735.6~857.7
857.7~1000.0
<0.005
0.007988
0.010455
0.012922
0.022143
0.044248
0.078955
0.115100
0.140896
0.150130
0.141863
0.117941
0.083330
0.047723
0.020718
0.005588
/
0.016852
0.024912
0.030314
0.032966
0.039646
0.047411
0.049041
0.038497
0.027529
0.042390
0.055308
0.049051
0.030705
0.013904
0.004269
Table S2. The average number size distribution of the bimodal size distribution
Size class (μm)
Quantity Proportion (averaged per person)
Standard deviation
<21.5
21.5~25.1
25.1~29.3
29.3~34.1
34.1~39.8
39.8~46.4
46.4~54.1
54.1~63.1
63.1~73.6
73.6~85.8
85.8~100.0
100.0~116.6
116.6~135.9
135.9~158.5
158.5~184.8
184.8~215.4
215.4~251.2
251.2~292.9
292.9~341.5
341.5~398.1
398.1~464.2
464.2~541.2
541.2~631.0
631.0~735.6
735.6~857.7
857.7~1000.0
<0.005
0.006572
0.013065
0.021522
0.055594
0.065905
0.085975
0.109173
0.132693
0.144683
0.134911
0.100702
0.058045
0.026841
0.010709
0.004418
0.003003
0.003528
0.004513
0.004989
0.004700
0.003765
0.002533
0.001398
0.000599
0.000164
/
0.017948
0.034184
0.048413
0.068620
0.072299
0.069034
0.049518
0.037744
0.062749
0.077350
0.069915
0.048540
0.025886
0.010625
0.003878
0.002008
0.002379
0.003439
0.004937
0.004418
0.003781
0.002695
0.001575
0.000713
0.000202
3 Results of Linear Regression Analysis
By using Linear Regression Analysis, the relationships between the distribution parameters of
the volume-based size distribution and each physiological characteristic of the subjects are
2
investigated. And the P-value and adjusted R value can be obtained to test the significance
level and goodness of the fitting results.
The fitting results show that the significant correlation can be found between the variance of
peak 1, and the height and weight of the subjects (P-value <0.02), and also between the mean of
peak 2, with the height and weight of the subjects (P-value <0.04). Fig. S3 shows the fitting results
and the fitting curves to demonstrate the correlation. However, although significant correlation can
be found, the average values of the means and variances in this work can also be used for
approximate evaluation of the volume-based size distribution of an adult.
Fig. S3 Relationships between the size distribution parameters of sneeze droplets and the
physiological characteristics of the subjects: (a) Relationships between the height and the variance
of bimodal distribution of Peak 1; (b) Relationships between the weight and the variance of
bimodal distribution of Peak 1; (c) Relationships between the height and the mean of bimodal
distribution of Peak 2; (d) Relationships between the weight and the mean of bimodal distribution
of Peak 2.