Impacts Of Extreme Temperature And Air Pollution On Respiratory Diseases

Global climate change has led to increased occurrence of extreme temperature events.In addition,rapid developments of industrialisation and urbanisation have result in air pollution.Both extreme temperature and air pollution have adverse effects on human health.Therefore,analysing the effects of extreme temperature and air pollution on human health have been research focus.Overview was used to summarise research status on the effects of extreme temperature?heat waves,cold spells,heat exposure and cold exposure?and air pollution(PM₁₀,NO₂ and SO₂)on respiratory diseases.We found deficiency of the research topic using overview,which could provide evidences for time series analysis.Then,the impacts of extreme temperature and air pollution on respiratory diseases in Beijing were explored.Distributed lag nonlinear model?DLNM?was used to analyse the impacts of extreme temperature on respiratory morbidity in Beijing;Generalised additive model?GAM?was employed to examine the association of indices for pollutants(PM₁₀,NO₂ and SO₂)and API with respiratory morbidity in Beijing;Bivariate Response Surface Model and GAM were used to analyse the interactions between extreme temperature and air pollution.The main results of this study were list below:1.Impact of extreme temperature on respiratory diseases?Overview?indicated that systematic reviews evaluating heat wave and heat exposure outnumbered those evaluating cold spell and cold exposure;In addition,heat and cold exposure were associated with respiratory morbidity.However,the effects of heat wave and cold spell on respiratory morbidity are unknown.Therefore,DLNM was used to analyse the impact of extreme temperature on respiratory diseases in Beijing.Results showed that?i?Ambient temperature related to respiratory morbidity exhibited a U-shaped association.The minimum-morbidity temperature was 21.5°C,which showed that respiratory diseases morbidity was lowest at comfort temperature.Heat waves and cold spells both have impacts on respiratory diseases in Beijing.In addition,the effects of cold spells were stronger than heat waves.?ii?Main impacts of different intensity extreme temperature?different thresholds and durations?on respiratory diseases indicated that the peak RR of cold spells on respiratory morbidity was observed in relatively mild cold spells.In addition,the impact discrepancy among cold spells with different durations was also the largest.There was a reduction in risk during extremely chilly cold spells,and the impact discrepancy among cold spells with different durations was also reduced.However,the risk of heat waves increased with the thresholds,and the greatest risk was found for extremely hot heat waves?threshold was equal or greater than 99 percentile?.In addition,the impacts of heat waves on respiratory morbidity were increased with durations raise.?iii?The added effects of heat waves and cold spells on respiratory morbidity were small.?iv?Populations were more susceptible to upper respiratory disease during heat waves and vulnerable to lower respiratory disease during cold spells.In addition,females were more vulnerable to heat waves and cold spells.2.Impact of air pollution on respiratory diseases?Overview?showed that NO₂ had a significant association with respiratory morbidity and mortality.The impacts of PM₁₀ and SO₂ on respiratory morbidity should be further studied.Therefore,we used GAM analysed the effects of air pollution on morbidity in Beijing.Results showed that?i?PM₁₀0 was the primary air pollutant from 2009 to 2012 in Beijing.Air pollutant was most associated with respiratory morbidity on the current day.The risk of air pollution on respiratory morbidity in single lag day decreased with lad day delayed.?ii?Females and children aged 10 to 17 had increased vulnerability to the effect of particulate matter.3.Based on the impacts of extreme temperature and air pollution on respiratory diseases respectively,we used temperature stratification to analyse the interactions between extreme temperature and air pollution.Results showed that?i?The risk of respiratory morbidity due to API and PM₁₀0 increased in cold temperature and extreme cold temperature strata.There is no association between air pollution and respiratory morbidity in heat temperature and extreme heat temperature strata.?ii?The association between particulate matter and respiratory morbidity was stronger in cold temperature stratum than extreme cold temperature stratum.Fitted curve between temperature and PM₁₀ in Beijing by our team indicated that threshold temperature corresponding to the highest PM₁₀ concentration was 2.3 It located in cold temperature stratum not extreme cold temperature stratum,which was closely related to our results.?iii?Children aged 10 to 17 and upper respiratory disease had increased risk in cold temperature stratum,while higher risks were observed in the aged and lower respiratory disease in extreme temperature stratum.In conclusion,the effects of cold spells and heat waves on respiratory morbidity in Beijing were different.The impacts of cold spells were prominent.The peak RR of cold spells on respiratory morbidity was observed in relatively mild cold spells.The effects of heat waves were secondary and the greatest risk was found for extremely hot heat waves.In addition,the risk of heat waves increased with durations raise.The added effects of heat waves and cold spells on respiratory morbidity were small.Based on temperature stratification,the impact of particulate matter on respiratory morbidity indicated that low temperature effects?cold temperature and extreme cold temperature strata?were stronger than high temperature effects?heat temperature and extreme heat temperature strata?.In addition,the association between particulate matter and respiratory morbidity was stronger in cold temperature stratum than extreme cold temperature stratum.In addition,the temperature threshold?2.3?corresponding to highest PM₁₀ concentration located in cold temperature stratum,which reflects the interactions between extreme temperature and air pollution on respiratory diseases.