Table 1. Characteristics of studies assessing the association between air pollutant exposure and pubertal development

Author	Country	Study design	Study period	Sample size	Age (years)	Sex Female (%)	Measured pollutants	Outcomes
Yang et al. [14]	China	Case-crossover	2015–2021	2,201	7.47±1.24	96.6	PM10, PM2.5, SO2, NO2, O3	The risk of precocious puberty
Wronka et al. [8]	Poland	Longitudinal cohort	2015–2018*	1,257	19–25	100	PM10, PM2.5, benzene, SO2, NO	The risk of early menarche
Zhao et al. [15]	Germany	Cross-sectional	1995–2009†	1,945	10	48.4	PM10, PM2.5, NO2, O3	Pubertal development at age 10 years assessed with estradiol and testosterone
Jung et al. [9]	South Korea	Cross-sectional	2010–2012	639	13–17	100	PM10	The risk of early menarche
Huang et al. [16]	Hong Kong	Birth cohort	1997–2008‡	4,074	9–12	47.5	PM10, SO2, NO, NO2	Pubertal stage at age 11 years assessed with Tanner stage
McGuinn et al. [17]	USA	Longitudinal cohort	2005–2012	437	6–8	100	Traffic metrics	Pubertal stage at 6–8 years assessed with Tanner stage

PM, particulate matter; SO₂, sulfur dioxide; NO₂; nitrogen dioxide; O₃, ozone.
Girls were born between 1993 and 1998.
The authors assessed children born between 1995 and 1999 when they reached the age of 10, between 2005 and 2009.
The authors assessed children born in 1997 when they reached the age of 9–12, between 2005 and 2008.