Table 1 Characteristics of study population and the prevalence of ARI symptom among the children in India, 2019–2021

PM2.5 quartiles

Q1 (2.5–34.4 µg/ m³)

25.34 (56,601)

1.96 (1.78–2.17)

P < 0.001

Q2 (34.5–51.5 µg/m³)

25.15 (56,188)

2.39 (2.17–2.63)

Q3 (51.6–78.2 µg/m³)

24.87 (55,552)

2.74 (2.54–2.96)

Q4 (78.3–128.9 µg/m³)

24.64 (55,034)

3.59 (3.36–3.84)

Current age of child

Mean ± SD

2.03 ± 1.43

0

19.99 (44,656)

3.34 (3.11–3.58)

P < 0.001

1

19.37 (43,278)

3.31 (3.07–3.57)

2

19.70 (44,007)

2.72 (2.52–2.93)

3

19.91 (44,482)

2.51 (2.31–2.71)

4

21.02 (46,952)

2.11 (1.94–2.31)

Sex of child

P < 0.001

Male

51.65 (115,381)

3.02 (2.87–3.18)

Female

48.35 (107,994)

2.54 (2.41–2.68)

Highest educational level of mother

P < 0.001

No education

21.68 (48,436)

2.87 (2.66–3.10)

Primary

12.83 (28,653)

3.38 (3.08–3.70)

Secondary

51.63 (115,339)

2.81 (2.66–2.96)

Higher

13.85 (30,947)

2.17 (1.96–2.39)

Household wealth quintile

P < 0.001

Poorest

26.90 (60,077)

3.2 (2.99–3.43)

Poorer

23.30 (52,044)

3.07 (2.86–3.30)

Middle

19.47 (43,485)

2.69 (2.48–2.92)

Richer

16.93 (37,807)

2.41 (2.19–2.65)

Richest

13.41 (29,962)

2.35 (2.12–2.60)

Type of place of residence

P < 0.001

Urban

20.32 (45,391)

2.3 (2.08–2.53)

Rural

79.68 (177,984)

2.97 (2.84–3.10)

Mother’s smoking habit

P < 0.001

Smokes cigarettes/tobacco

5.60 (12,510)

4.13 (3.58–4.76)

Does not smoke

94.4 (210,865)

2.75 (2.64–2.87)

Type of cooking fuel used in the HH

P < 0.001

Clean fuel

42.94 (95,919)

2.59 (2.44–2.76)

Unclean fuel

57.06 (127,456)

2.97 (2.82–3.12)

Total (n)

223,375

2.78 (2.68–2.91)