Onset of respiratory symptoms among Chinese students: associations with dampness and redecoration, PM₁₀, NO₂, SO₂ and inadequate ventilation in the school

Abstract

Objective: To study onset of respiratory symptoms among students in China in relation to the school and the home environment.

Methods: A two-year prospective cohort study among 1325 students in eight schools. Air pollution was measured at baseline in the schools. Respiratory symptoms and the home environment were assessed by a questionnaire.

Results: The 2-year onset was 14.3%, 23.2%, 15.4%, 4.7% and 37.3% for wheeze, daytime attacks of breathlessness, nocturnal cough, nocturnal wheeze/breathlessness and respiratory infections, respectively. The mean concentrations of PM₁₀, SO₂, NO_2, ozone and CO₂ in the classrooms were 129 µg/m³, 68.0 µg/m³, 43.2 µg/m³, 8.6 µg/m³ and 1208 ppm, respectively. Environmental tobacco smoke (ETS), dampness/mold at home and ozone in the classroom were associated with onset of wheeze. Onset of daytime breathlessness was associated with redecoration and dampness/mold at home and CO₂ and relative air humidity (RH) in the classrooms. Dampness/mold at home, PM₁₀, CO₂ and RH in the classrooms and outdoor PM₁₀, SO₂ and NO₂ were associated with onset of nocturnal cough. Onset of nocturnal wheeze/breathlessness was associated with dampness/mold at home and RH and PM₁₀ in the classrooms. Respiratory infections were more common at higher levels of outdoor PM₁₀.

Conclusions: Air pollution (PM₁₀, ozone, SO₂ and NO₂) and inadequate ventilation flow in the classrooms (indicated by CO₂ > 1000 ppm) and ETS, dampness or mold and chemical emissions from redecoration at home can increase onset of respiratory symptoms.

Keywords:

• Air pollution
• children
• indoor
• longitudinal study
• particulate matter
• respiratory symptoms

Acknowledgements

The authors gratefully acknowledge the Institute of High School Students Health Care in Taiyuan, all children, their parents/guardians and the teachers of participated schools.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Author contributions

Conceived and designed the experiments: DN XZ ZHZ. Performed the experiments: DN XZ ZHZ. Analyzed the data: CHL TL XB XZ. Contributed reagents/materials/analysis tools: CHL TL XB DN XZ. Contributed to the writing of the manuscript: DN XZ.

Additional information

Funding

This study was funded by the National Key Research and Development Program of China (2017YFC0702700), the National Natural Science Foundation of China (81861138005), the Natural Science Foundation of Shanxi Province of China (2016011080), the Key Research and Development (R&D) Projects of Shanxi Province (201803D31021), Shanxi One Hundred Excellent Experts Project (nr 9) and the Swedish Research Council Formas (348–2011-7402). Svenska Forskningsrådet Formas.