Table 2.

Meta-regression estimation results explaining traffic contribution to particulate matter.

Variables	Mean	Std. Dev.	95% Bayesian interval		Odds ratios	Std. Dev.	95% Bayesian interval
Europe, North America or Oceania	−0.443	0.162	−0.768	−0.129	0.642	0.105	0.464	0.878
Published after 2005	−0.326	0.179	−0.670	0.029	0.722	0.133	0.511	1.030
Population less than 500,000 people	−0.269	0.097	−0.459	−0.079	0.764	0.074	0.631	0.924
PM10	0.171	0.091	−0.008	0.350	1.191	0.108	0.991	1.419
Study-specific random effect mean	−0.577	0.212	−0.986	−0.154	–	–	–	–
Study-specific random effect variance	0.556	0.091	0.393	0.748	–	–	–	–
Observation-level variance	0.265	0.033	0.208	0.336	–	–	–	–
Note: For description of the explanatory variables, see Table 1.