BackgroundAir pollution has been identified as a terrible environmental problem in China. However, no study has systematically assessed whether air pollution has adverse effects on human physiological function. MethodsThis study was based on longitudinal data collected by the Kailuan Cohort Study, which was conducted in the area of Kailuan community, Tangshan City, China. 11 hospitals were responsible for the health care of the community. We only used cohort data between 2006 and 2008, as we only had these two years' air pollution data. We assessed each participant twice with a standardised questionnaire assessment, health examination, and laboratory assessment. The health examination and laboratory assessment included heart function, renal function, haematopoietic function, metabolic endocrine function, liver function, and inflammatory response function. The questionnaire collected individual characteristics (age, sex, weight, height, smoking status, drinking status, physical activity, dietary salt intake, financial income, work type, education level, and medical history, etc). Community level of daily concentrations of particles (PM10), sulphur dioxide (SO2) and nitrogen dioxide (NO2) was provided by the Tangshan Environmental Monitoring Centre. We used generalised additive mixed models to examine the effects of community level of daily air pollutants on physiological function, while controlling for random effects of participants and other potential confounders. This study was approved by the University of Queensland's behaviour and social sciences ethical review committee (2014001075). Written informed consent was obtained for each participant. FindingsOut of the 155 418 residents, 101 510 (65·31%; 81 110 (82%) men and 20 400 women) who provided a written informed consent, were enrolled in the Kailuan study since 2006. We followed up 27 685 participants twice between 2006 and 2008. Age ranged from 18 to 90 years, with mean of 47 years (SD 11·3). About 60% of the participants were not smokers or drinkers in 2006. The prevalence of diabetes was 7·7% in 2006, and 20·9% of participants had a history of hypertension. Increased concentrations of PM10, SO2, and NO2 were significantly associated with decreases in all categories of physiological function, such as increase in heart rate and blood pressure (heart function), increase in urine creatinine and urea (renal function), decrease in haemoglobin and white blood cell (hematopoietic function), increase in cholesterol, low-density lipoprotein, high-density lipoprotein, and the ratio of low-density lipoprotein to high-density lipoprotein (metabolic endocrine function), increase in serum albumin, glutamic-pyruvic transaminase, and total bilirubin (liver function), and increase in C-reactive protein (inflammatory response function). Generally, elderly people, women, and people who were overweight were more susceptible to air pollution than young people, men, and people who were normal weight. InterpretationAir pollution could systemically damage human physiological function. Effective air pollution control is essential for disease prevention. We used community level of air pollution to estimate individual exposures rather than personal air pollution exposure data. This may underestimate the effects of air pollutants on physiological function. FundingUniversity of Queensland Research Fellowship (YG). No funding bodies had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.