Association of Air Pollution and Illness-Related School Absenteeism for Elementary Students in Jiangsu Province, China

Background: Assessing the impacts of  air pollution on school absenteeism due to illness is critical for developing future preparedness response strategies for the sensitive elementary students.  Methods: We collected 693,081 absenteeism records due to illness from 2,564 elementary schools across Jiangsu Province, China in the 2016-17 academic year. Exposure levels of the six major air pollutants, including carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), coarse and fine particle (PM10, PM2.5), and sulfur dioxide (SO2), were estimated via Kriging interpolation of the measured data from routine monitoring network. We examined the associations between air pollutants and illness-related absenteeism using a time-stratified case-crossover design.  Findings: We found that an increase of 10 µg/m3 in the current-day concentration of air pollutants, including PM2.5, PM10, NO2, SO2, and 100 µg/m3 for CO, was overall associated with absenteeism due to illness overall, with a 0·6% to 16·8% increase in the risk of absenteeism. Students in up to 40% illness-related absenteeism received home nursing instead of going to hospital. The increase in the number of illness cases associated with the above five air pollutants estimated based on the illness-related absence data was 43-52% higher than that accessed based on hospital visit records. The risk due to O3 exposure alone existed only for students frequently absented (>5 times during the study period). After controlling with other pollutants, the risk from PM2·5 decreased but persisted while risk from O3 appeared. Adjustment for PM10 and O3 led to a risk boost for multiple pollutants.    Interpretation: Our findings validate the use of illness-related absence records in studies for public health purposes and provide evidence of the health risk of air pollution in school-aged children. Improvement in air quality and home health care education are warranted for children’s health benefits.  Funding: National Natural Science Foundation of China and the Jiangsu Social Development Project. Declaration of Interest: We declare no competing interests.