A Time Series Analysis of Atmospheric NO₂ Pollution and Outpatient Visits of Children for Respiratory Diseases in Yuexiu District of Guangzhou, China

Objective To explore the effect of atmospheric NO₂ concentration on outpatient visits of children for respiratory diseases in Yuexiu District of Guangzhou, China.

Methods Data on atmospheric NO₂, meteorology, and the outpatient visits for respiratory diseases were collected in a children's hospital in Yuexiu District of Guangzhou from 2014 to 2016. Spearman rank correlation analysis and time series analysis using a generalized additive model were applied to study relationship and its lag effects between atmospheric NO₂ concentration and concurrent pediatric outpatient visits for respiratory diseases.

Results In 2014, 2015, and 2016, the annual means of atmospheric NO₂ concentration in Yuexiu District were 61.30, 60.46 and 60.81 μg/m³, respectively, and the days in which the NO₂ concentrations over the national standard values were 70, 64 and 62, respectively. The time series analysis showed significant effect of atmospheric NO₂ concentration on respiratory outpatient visits from day 0 to day 7, with the greatest effect on the lag0 d. An excess risk (ER) of 1.45% (95% CI: 0.93%-1.98%) was on lag day 0 (lag0). The greatest cumulative lag effect and an ER of 3.07% (95% CI: 2.04%-4.10%) were observed on lag days 0-6 (lag06 d).

Conclusion The increase in NO₂ in Yuexiu District of Guangzhou from 2014 to 2016 led to outpatient visits increasing for respiratory diseases.