Table 3. Correlation between travel speed and number and mass concentration of fumes.

Size distribution (µm)	Travel speed	Mean number concentratrion (number per litre)						Mean mass concentratrion (µg per m3)
		Distance = 23 cm			Distance = 41 cm			Distance = 23 cm			Distance = 41 cm
		N	r	p-value	N	r	p-value	N	r	p-value	N	r	p-value
0.35–0.5	High	6	−0.68	0.01	6	−0.71	<0.01	6	−0.73	<0.01	6	−0.77	0.01
	Low	6	−0.71	<0.01	6	−0.67	0.03	6	−0.77	0.02	6	−0.72	<0.01
0.5–0.75	High	6	−0.86	<0.01	6	−0.78	<0.01	6	−0.71	0.01	6	−0.56	0.01
	Low	6	−0.83	<0.01	6	−0.77	<0.01	6	−0.7	0.03	6	−0.78	<0.01
0.75–1	High	6	−0.73	0.01	6	−0.86	<0.01	6	−0.76	<0.01	6	−0.63	0.02
	Low	6	−0.71	0.04	6	−0.89	0.01	6	−0.79	0.04	6	−0.68	<0.01
1–2	High	6	−0.78	0.02	6	−0.74	0.02	6	−0.76	0.01	6	−0.79	0.03
	Low	6	−0.79	0.01	6	−0.79	<0.01	6	−0.77	<0.01	6	−0.76	<0.01
2–3.5	High	6	−0.63	0.02	6	−0.87	<0.01	6	−0.78	0.03	6	−0.66	0.01
	Low	6	−0.60	<0.01	6	−0.85	0.04	6	−0.80	<0.01	6	−0.76	<0.01
3.5–5	High	6	−0.72	<0.01	6	−0.69	<0.01	6	−0.77	0.03	6	−0.57	0.02
	Low	6	−0.75	0.02	6	−0.75	<0.01	6	−0.76	<0.01	6	−0.74	<0.01
5–6.5	High	6	−0.64	<0.01	6	−0.74	0.02	6	−0.71	<0.01	6	−0.72	<0.01
	Low	6	−0.69	0.02	6	−0.81	0.03	6	−0.87	0.01	6	−0.63	<0.01
>6.5	High	6	−0.77	<0.01	6	−0.74	<0.01	6	−0.83	0.02	6	−0.68	<0.01
	Low	6	−0.74	0.03	6	−0.82	0.01	6	−0.79	<0.01	6	−0.67	0.01
Total	High	6	−0.76	<0.01	6	−0.79	<0.01	6	−0.75	<0.01	6	−0.68	<0.01
	Low	6	−0.77	0.03	6	−0.76	<0.01	6	−0.74	<0.01	6	−0.71	0.02