Fig 1.
Selection and screening of study participants.
Table 1.
The content of the test and the weighting of the scores for each academic level.
Fig 2.
Distribution of AQI and Air pollutants indicators by provinces.
A: Air Quality Index (AQI), B: CO (Carbon Monoxide), C: NO2 (Nitrogen Dioxide), D: O₃ (Ozone), E: PM10 (Particulate Matter 10 micrometers), F: PM2.5 (Particulate Matter 2.5 micrometers), G: SO2 (Sulfur Dioxide). Map rendered using public domain geographic data from Natural Earth (www.naturalearthdata.com). All map layers are CC0 licensed. Map generated with R (ggplot2 + sf).
Fig 3.
Distribution of average physical fitness scores across 30 provinces.
Including body BMI, FVC (ml), Sit-and-reach(cm), 1-min sit-ups/pull-ups(number), standing long jump (m), 50m sprint (sec), 50m × 8 round-trip running (sec), 800m/1000m(sec) and 1-minute rope skipping(number). Map rendered using public domain geographic data from Natural Earth (www.naturalearthdata.com). All map layers are CC0 licensed. Map generated with R (ggplot2 + sf).
Fig 4.
Association between AQI, air pollutants and physical fitness score in Chinese students aged 7-22 years across three models.
model 1: adjusted for age (numeric variable), sex (categorical variable), residence (categorical variable), and province (categorical variable). model 2: further adjusted for moderate-to-vigorous physical activity and outdoor activity, muscle-strengthening exercise, parental support for physical activity, and parental preference for physical activity (all categorical variables). model 3: further adjusted for temperature (numeric variable) and humidity (numeric variable).