Table 1 Overview of placental epigenetic targets in association with air pollution exposure

  Janssen et al. [35]

240 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

UPLC/MS-MS

+ 5 μg/m³ PM_2.5 during the implantation period (6–21 days after conception)

Global methylation − 1.08%, 95% CI − 1.80 to − 0.36%, p = 0.004

+ 5 μg/m³ PM_2.5 during the first trimester

Global methylation − 2.41%, 95% CI − 3.62 to − 1.20%, p = 0.0001

+ 5 μg/m³ PM_2.5 during the second trimester

Global methylation − 1.51%, 95% CI − 2.66 to − 0.36%, p = 0.01

+ 5 μg/m³ PM_2.5 during the entire pregnancy

Global methylation − 2.19%, 95% CI − 3.65 to − 0.73%, p = 0.004

  Kingsley et al. [36]

471 mother-newborn pairs from the RICHS birth cohort, USA

Bisulfite-PCR-pyrosequencing

≤ 150 m primary highway or primary road or ≤ 50 m from secondary road

Living close to major roadway: LINE-1 − 0.82%, 95% CI − 1.57 to − 0.07%, p = 0.03

AluYb8: no association, p = 0.07

  Cai et al. [37]

181 mother-newborn pairs (80 fetal growth restriction newborns, 101 normal newborns) from Wenzhou, China

Bisulfite-PCR-pyrosequencing

+ 10 μg/m³ PM₁₀ during the first trimester of pregnancy

Fetal growth restricted newborns: LINE-1 − 1.78%, 95% CI − 3.35 to − 0.22% , p < 0.05

Normal newborns: LINE-1 no association

  Maghbooli Z et al. [38]

Nested case-control (n = 50/50) of pregnant women in Tehran, Iran

RP-HPLC

PM_2.5 and PM₁₀ during the first trimester

Global methylation: r = 0.26 (p = 0.01) and r = 0.38 (p = 0.0001) respectively

  Abraham et al. [39]

668 mother-newborn pairs from the EDEN cohort, France

Bisulfite-PCR-pyrosequencing

+ 10 μg/m³ PM₁₀ day before birth

Global methylation: Alu: β = 0.08; p = 0.01

LINE-1: β = 0.09; p = 0.28

  Janssen et al. [49]

381 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

Bisulfite-PCR-pyrosequencing

+ 7.8 μg/m³ PM_2.5 during the first trimester of pregnancy

MT-RNR1 + 1.27%, 95% CI 0.23 to 2.32%, p < 0.05

D-loop + 0.44%, 95% CI 0.12 to 0.75%, p < 0.05

+ 3 μg/m³ PM_2.5 during the entire pregnancy

MT-RNR1 + 0.91%, 95% CI 0.56 to 4.18%, p < 0.05

D-loop + 0.21%, 95% CI − 0.003 to 1.02%, p > 0.05

  Cai et al. [37]

181 mother-newborn pairs (80 fetal growth restriction newborns, 101 normal newborns) from Wenzhou, China

Bisulfite-PCR-pyrosequencing

+ 10 μg/m³ PM₁₀ during the first trimester of pregnancy

Fetal growth restricted newborns: HSD11B2 + 1.03%, 95% CI 0.07 to 1.98%, p < 0.05

+ 10 μg/m³ PM₁₀ during the second trimester of pregnancy

Fetal growth restricted newborns: HSD11B2 + 2.23%, 95% CI 0.69 to 3.76%, p < 0.05

Total population: HSD11B2 + 1.42%, 95% CI 0.24 to 2.57%, p < 0.05

+ 10 μg/m³ PM₁₀ during the entire pregnancy

Total population: HSD11B2 + 1.98, 95% CI 0.53 to 3.43%, p < 0.05

  Saenen et al. [48]

361 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

Bisulfite-PCR-pyrosequencing

+ 7.5 μg/m³ PM_2.5 during the second trimester

LEP − 1.4%, 95% CI − 2.7 to − 0.19%, p = 0.02

  Neven et al. [45]

463 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

Bisulfite-PCR-pyrosequencing

+ 3.84 μg/m³ PM_2.5 during the entire pregnancy

APEX1 + 7.34%, 95% CI 0.52 to 14.16%, p = 0.009

OGG1 + 13.06%, 95% CI 3.88 to 22.24%, p = 0.005

ERCC4 + 16.31%, 95% CI 5.43 to 27.18%, p = 0.003

p53 + 10.60%, 95% CI 4.46 to 16.74%, p = 0.003

DAPK1 − 12.92%, 95% CI − 22.35 to − 3.49%, p = 0.007

+ 0.36 μg/m³ BC during the entire pregnancy

APEX1 + 9.16%, 95% CI 4.06 to 14.25%, p = 0.005

ERCC4 + 27.56% 95% CI 17.58 to 37.55%, p < 0.0001

  Nawrot et al. [42]

407 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

Bisulfite-PCR-pyrosequencing

+ 8.9 μg/m³ PM_2.5 during the third trimester

Log(fold change) NPAS2 0.16, 95% CI 0.06 to 0.27, p = 0.002

Log(fold change) CRY1-2 0.59, 95% CI 0.22 to 0.95, p = 0.002

Log(fold change) PER1 − 0.51, 95% CI − 0.90 to − 0.13, p = 0.001

Log(fold change) PER3 0.42, 95% CI 0.18 to 0.67, p = 0.001

+ 7.9 μg/m³ PM_2.5 during the first trimester

Log(fold change) CLOCK − 0.59, 95% CI − 0.93 to − 0.25, p < 0.001

  Tsamou et al. [65]

210 mother-newborn pairs from the ENVIRONAGE birth cohort, Belgium

qRT-PCR

+ 5 μg/m³ PM_2.5 during the first trimester of pregnancy

miR-20a + 70.9%, 95% CI 16.7 to 150.3%, p = 0.007

miR-21 + 73.7%, 95% CI 11.7 to 170.1%, p = 0.015

+ 5 μg/m³ PM_2.5 during the second trimester of pregnancy

miR-146a − 30.9%, 95% CI − 48.0 to − 8.1%, p = 0.012

miR-222 − 25.4%, 95% CI − 43.0 to − 2.4%, p = 0.034

miR-21 − 33.7%, 95% CI − 53.2 to − 6.2%, p = 0.022