Table 1 Details of the studies included in the review

 Santi, et al. 2016 [25]

Italy, Modena

Nov 2014 to Feb 2015

406 men from the Clinical Pathology of the Nuovo Ospedale Civile Sant Agostino Estense (NOCSAE)

32.3 ± 5.2

Retrospective cohort study

PM10 (4–155 μg/m³)

Volume, concentration (× 10⁶/mL), total sperm number, typical/atypical forms (%),progressive motility (%), non-progressive motility (%), total motility (%), leucocytes

PM2.5 (1–101 μg/m³)

 Wu, et al. 2016 [27]

China, Wuhan

March 2013 to Dec 2015

1759 men, partners of women undergoing assisted reproductive technology

34.4 ± 5.4

Retrospective cohort study

PM10 (67.2–197 μg/m³)

Concentration (× 10⁶/mL), sperm count, total motility (%), progressive motility (%),

PM2,5 (27.3–172.4 μg/m³)

Radwan, et al. 2016 [23]

Poland, Lodz

Jan 2008 to Apr 2011

327 men from infertility clinic

32.3 ± 4.4

Cross-sectional

PM10 (11.78–120.5 μg/m³)

Concentration (× 10⁶/mL), motility (%), sperm with abnormal morphology (%), DFI(%), HDS(%), CASA parameters: VSL, VCL, LIN; FSH, E₂, T

PM2.5 (7.99–93.89 μg/m³)

SO₂ (9.12–167.9 μg/m³)

CO (0.15–1.85 μg/m³)

NO_x (2.17–215.14 μg/m³)

 Jurewicz, et al. 2015 [34]

Poland, Lodz

–

212 men from infertility clinic

22–57

Cross-sectional

PM10 (11.59–122.8 μg/m³)

Sperm aneuploidy, sperm concentration (× 10⁶/mL), total motility (%), abnormal morphology (%)

32.25 ± 5.72

PM2,5 (7.99–95.22 μg/m³)

O₃ (12.33–79.75 μg/m³)

SO₂ (10.11–160.90 μg/m³)

CO (0.17–1.79 μg/m³)

NO_x (2.32–218.30 μg/m³)

 Radwan, et al. 2015 [35]

Poland, Lodz

Jan 2008 to Apr 2011

181 men from infertility clinic

32.1 ± 4.6

Cross-sectional

1 PAH metabolites in urine 1-OHP (0.04–2.03 μg/g creat)

Sperm aneuploidy, sperm concentration (× 10⁶/mL), total motility (%), normal sperm morphology (%),

 Zhou, et al. 2014 [21]

China, Chongqing

2007

1346 men from family planning institutions

20–40

Cross-sectional

PM10 (66–160.5 μg/m³)

Volume, concentration (× 10⁶/mL), progressive motility (%), total motility, morphology (normal forms %), CASA sperm motility parameters (VCL, VSL, VAP, BCF, ALH, LIN, STR)

SO₂ (31-101 μg/m³)

NO₂ (19.5–53.5 μg/m³)

 Jurewicz, et al. 2013 [24]

Poland, Lodz

–

277 men from infertility clinic

32 ± 4.6

Cross-sectional

1 PAH metabolite in urine 1-OHP (0.02–2.03 μg/g creat)

Volume, concentration (× 10⁶/mL), motility (%), atypical sperm (%),static sperm (%), CASA parameters: VAP, VSL, VCL, BCF, ALH, DFI (%)

 Song, et al. 2013 [22]

China, Pearl River Delta

Jul 2010 to Aug 2011

53 men from infertility clinic

Cross-sectional

16 PAHs in blood

Concentration (× 10⁶/mL), volume, motility (grade A, grade B, grade C)

 Han, et al. 2011 [31]

China, Chongqing

Dec 2007

232 men from Chongqing Family Planning Research Institute

31.89 ± 5.53

Cross-sectional

4 PAH metabolites in urine

Apoptotic marker (Annexin V⁻/PI⁻ spermatozoa %, Annexin V⁺/PI⁻ spermatozoa %, PI⁺ spermatozoa %, comet parameters (tail%, tail length, TDM)

1-OHP (μg/g creatinine)

9-OHPh (μg/g creatinine)

2-OHFIu (μg/g creatinine)

2-OHNa (μg/g creatinine)

 Hammoud, et al. 2010 [20]

USA, Salt Lake City

2002 to 2007

1699 semen analyses and 877 inseminations

32.8 ± 6.57

Ecological study

PM2.5 (5-24 μg/m³)

Motility, concentration (×10⁶/mL), morphology (normal forms %)

 Hansen, et al. 2010 [19]

USA, Wake County, Shelby County and Galveston County

2002 to 2004

228 men, partners of pregnant women

18–40

Cross-sectional

O₃ (2–83.2 ppb)

Concentration (× 10⁶/mL), count, morphology (normal forms %), abnormal morphology (%), abnormal head (%), abnormal midsection (%), abnormal tail (%), cytoplasmic droplets (%), CMA (%), DFI (%)

PM2.5 (2.1–62.7 μg/m³)

 Xia, et al. 2009a [28]

China, Nanjing

March 2004 to Jul 2007

513 infertile men and 273 fertile men as controls

28.65 ± 4.51 for infertile males and 29.32 ± 4.51 for controls

Cross-sectional

4 PAH metabolites in urine

Volume, concentration (×10⁶/mL), sperm number per ejaculum, sperm motility

1-N (μg/g creat)

2-N(μg/g creat)

1-OHP (μg/g creat)

2-OHF(μg/g creat)

 Xia, et al. 2009b [29]

China, Nanjing

March 2004 to Jul 2007

542 men

No information -based on abstract

Cross-sectional

4 PAH metabolites in urine

Volume, concentration (× 10⁶/mL), sperm number per ejaculum, sperm motility

1-N (μg/g creat)

2-N(μg/g creat)

1-OHP (μg/g creat)

2-OHF(μg/g creat)

 Rubes, et al. 2007 [32]

Czech, Teplice

Sep 1995 to Sep 1997

36 men

19–21

Longitudinal study

SO₂ (μg/m³)

%DFI, GSTM1 genotype

NO_x (μg/m³)

PM10 (16.9–76.3 μg/m³)

PAH (21.4–221.9 ng/m³)

 Sokol, et al. 2006 [18]

USA, Los Angeles

Jan 1996 to Dec 1998

48 sperm donors from sperm donor bank

19–35 mean 25.3 ± 4.7

Retrospective cohort study

O₃ (1.69–47.51 ppb)

Concentration (×10⁶/mL), motility (×10⁶)

NO₂ (9.04–79.80 ppb)

CO (0.37–3.86 ppm)

PM10 (6.84–101.88 μg/m³)

 Rubes, et al. 2005 [26]

Czech, Teplice

Sep 1995 to Sep 1997

36 men

19–21

Prospective cohort study

SO₂ (μg/m³)

Count, concentration (×10⁶/mL), volume, motility (%), normal sperm head morphology (%), normal morphology (%), straight line velocity, curvilinear velocity, linearity, %DFI

NO_x (μg/m³)

PM10 (μg/m³)

PAH (ng/m³)

 Selevan, et al. 2000 [17]

Czech, Teplice, Prachatice

1993 to 1994

408 men from Hygiene Station

18

Prospective cohort study

PM10 (3.1–832.0 μg/m³)

Semen volume, concentration (×10⁶/mL), total count, motility (%), total progressive, normal morphology (%), normal heads (%), VSL, VCL, LIN, sperm chromatin structure

SO₂ (1–697.9 μg/m³)

CO (0–5.50 mg/m³)

NO_x (0–367.20 μg/m³)

 Robbins, et al. 1999 [33]

Czech, Teplice, Prachatice

Subset of 32 men

No information -based on abstract

Prospective cohort study

No information-based on abstract

Sperm aneuploidy

 Calogero, et al. 2011 [37]

Italy

1.) 15June to 15July 2.) 1 to 31Jan

36 men working at motorway tollgates; 32 unexposed men

28–47 37.1 ± 5.5

Cross-sectional

NO_x (μg/m³)

LH, FSH, T, sperm concentration (×10⁶/mL), total count, total motility (%), progressive motility (%), normal forms (%), sperm chromatin integrity, DFI (%)

SO_x (μg/m³)

 Boggia, et al. 2009 [38]

Italy

2000 to 2004

307 men working at motorway

23–57 mean 37.16

Cross-sectional

NO₂ (μg/m³)

FSH, LH, T, sperm count, motility (%), morphology,

 Guven, et al. 2008 [36]

Turkey

–

38 men working at motorway and 35 men working at office as a control group

35.2 ± 6.4 (study group) and 33.7 ± 6.7 (control group)

Cross-sectional

Traffic pollutants mainly the diesel

Concentration (×10⁶/mL), motility, morphology

 De Rosa, et al. 2003 [39]

Italy

Jan2000 to Jan2002

85 men working at motorway and 85 control men randomly selected;

38.6 ± 0.8 (study group) and 39.6 ± 0.7 (control group)

Cross-sectional

CO (9-27 mg/m³)

FSH, LH, T, sperm count, volume, motility, morphology, sperm membrane function, forward progression, sperm kinetics: VSL, VCL, LIN, ALH,

NO (58–398 mg/m³)

SO (9–27 μg/m³)

Pb (0.9–4.2 μg/m³)