Lag effects of size-fractionated particulate matter pollution on outpatient visits for respiratory diseases in Lanzhou, China.

Abstract

A large body of evidence suggests that an increase in atmospheric particulate matter (PM) concentrations will lead to an increase in morbidity due to adverse health conditions, such as respiratory diseases (RESD). Lanzhou is located in northwest China, central Gansu Province. Due to limited research and data, the impact of PM on human health have not been systematically acknowledged. The aim of the study is to investigate the association between size-fractionated PM pollution and outpatients visits for RESD. Data on outpatient visits for RESD, air pollutants and meteorological indices in Lanzhou were collected from 1 February 2014 - 31 December 2017, and the associations of three types of PM (PM2.5, PMC, and PM10) with outpatient visits for RESD were evaluated using generalized additive models (GAMs). Findings showed that PM2.5 and PMC had the most significant impact on outpatient visits for RESD at seven cumulative lag days. PM10 was not significantly associated with outpatient visits for RESD. In subgroup analysis, the impact of atmospheric PM on outpatient visits for RESD was significantly modified by gender and age; men, and children aged 0-5 years old, were more sensitive to PM2.5 pollution. Increased atmospheric PM concentration is associated with an increase in outpatient visits for RESD, and it has a lag effect. The increase in outpatient visits for RESD appears to be driven by increased PM2.5 concentrations. The results obtained may provide reference values for formulating preventive strategies to protect the population from the adverse impact of PM pollution.