Objective To investigate the level of formaldehyde pollution in the air of public places in Hohhot, Bayannur, Tongliao and Hulunbuir cities of Inner Mongolia Autonomous Region in China, and to evaluate its carcinogenic risk to practitioners.

Methods Data from the public health hazard monitoring project were used to analyze the concentration of formaldehyde in the indoor air of hotels, barbershops and beauty shops in Hohhot, Bayannur, Tongliao and Hulunbuir cities. The United States Environmental Protection Agency (US EPA) health risk assessment method was used to evaluate the carcinogenic risk of formaldehyde in the air of the above three types of public places.

Results A total of 1 367 samples of formaldehyde monitoring data were obtained, with 289, 398, 297 and 383 samples, respectively, from Hohhot, Bayannur, Tongliao and Hulunbuir. There were 990 samples from hotels, 172 samples from barbershops, and 205 samples from beauty shops. The M (P₂₅, P₇₅) of formaldehyde mass concentrations in hotels, barbershops and beauty shops were 0.060 (0.030, 0.100), 0.050 (0.030, 0.088) and 0.050 (0.020, 0.090) mg/m³, respectively, with a significant difference between the three types of public places (H = 17.20, P < 0.001). The overall qualification rate of formaldehyde in the air of the three types of public places was 78.2%(1 069/1 367), with a qualification rate of 75.9%(751/990) in hotels, 86.6%(149/172) in barbershops, and 82.4%(169/205) in beauty shops, and there was a significant difference between the three types of public places (χ² = 12.51, P < 0.05). The carcinogenic risk of male in these three types of public places was 6.93×10^-5, 8.66×10^-5 and 7.80×10^-5, respectively, and that of female was 6.49×10^-5, 8.11×10^-5 and 7.30×10^-5, respectively.

Conclusion Formaldehyde in the indoor air of the three types of public places in Inner Mongolia Autonomous Region has a certain carcinogenic risk to practitioners.