Effects Of Indoor PM2.5 On Pulmonary Function And Respiratory Symptoms In Adults With Asthma

Objective: To study the effects of indoor PM2.5 on pulmonary function and respiratory symptoms in adults with asthma.Methods:As a part of the special project "the impact of air pollution on chronic respiratory inflammatory diseases" in Hebei Province,63 adult asthmatic patients who were reexamined in the outpatient department of the First Pulmonary and Critical Care Medicine of the Second Hospital of Hebei Medical University from February 2017 to April 2019 were selected as the study objects by the method of follow-up study.After 14 consecutive days of indoor and outdoor PM2.5 collection,pulmonary function test and respiratory symptoms evaluation,the effects of indoor PM2.5 on pulmonary function and respiratory symptoms were analyzed.Results:1.During the study period,indoor and outdoor PM2.5 were significantly positively correlated.2.The concentration of indoor PM2.5 was negatively correlated with indexes of pulmonary function PEF,FEV1,FEV1/FVC,MEF75,MEF50 and MEF25,which was statistically significant(P<0.05).This negative correlation has a certain hysteresis effect.With a 0-day lag,the pulmonary function indexes PEF,MEF75 and MEF25 in asthmatic patients decreased to different degrees as the indoor PM2.5 concentration increased.With a 2-day lag,the pulmonary function indexes PEF,FEV1 and MEF50 in asthmatic patients decreased to different degrees as the indoor PM2.5 concentration increased.There was no significant difference between the low and medium dose ICS+LABA group and the non-medication group.There was no significant difference between the other sensitive group and the non-sensitive group compared with the haze-sensitive group.3.There was a positive correlation and hysteresis effect between indoor PM2.5 concentration and respiratory symptoms(wheezing,chest tightness,cough,expectoration)of asthmatic patients,which was statistically significant(P<0.05).The low-dose ICS+LABA group was more likely to have wheezing symptom and less likely to have cough symptom than the non-medication group,the non-sensitive group was less likely to have wheezing symptom than the haze-sensitive group,and the non-sensitive group and other sensitive group were less likely to have chest tightness symptom than the haze-sensitive group.Conclusions:1.There was a positive correlation between indoor and outdoor PM2.5 concentrations.2.Indoor exposure to high concentrations of PM2.5 can lead to the decline of pulmonary function and the increase of respiratory symptoms in adult asthmatic patients,which has a certain hysteretic effect.3.Haze is one of the risk factors of asthmatic patients who is sensitive to haze.