| Cave dwelling is an ancient and unique type of residence in the Loess Plateau of China,where lies southeastern portion of Gansu province,western mountainous region of Henan province and the central and southern part of Shanxi province,The economics in this regions are less-developed,and the majority of the local dwellers rely on traditional solid fuels for cooking and heating,which can emit large amounts of particles into both indoor and outdoor environments,inducing adverse impacts on household environment and human health.In this paper,the real-time household concentrations of PM2.5 and resident's blood pressure were measured in different cave dwellings during winter in 2019.And the effects of cooking,heating activies,fuel types and meteorological conditions on indoor and outdoor PM2.5 concentration in cave dwelling were analyzed.The relative risk?RR?and population attributable fraction?PAFs?of acute lower respiratory infection?ALRI?,lung cancer?LC?,ischemic heart disease?IHD?,stroke,and chronic obstructive pulmonary disease?COPD?becauce of the PM2.5 exposur were calculated based on the integrated exposure-response model?IER?.Using mixed effects model,the quantitative relationship between PM2.5 exposure and resident's blood pressure.The main results are divided into the following two parts:?1?PM2.5 pollution characteristics and its influencing factors of indoor and outdoor cave dwellings:The average daily PM2.5 concentrations in indoor and outdoor cave dwellings were 193±71?g/m3and 148±19?g/m3,respectively.The concentrations were significantly higher than those of cities and in the same area,and were nearly2.6and 2.0 times higher than the ambient air quality standard?75?g/m3?.And the indoor PM2.5 concentration in the cave dwellings was significantly higher than that of the outdoor,various solid fuel combustion was the main source of household PM2.5pollution in the cave dwelling.And cooking and heating activities were the the main artificial factors that affected the indoor and outdoor PM2.5 concentrations in the cave dwelling.Various pollutants were emitted when solid fuels were consumed during cooking and heat acticities,and increase the PM2.5 concentration in cave dwellings.Cooking and heating activities with different energies made a great variation in the household PM2.5 air pollution,cave dwelling in which biomass were consumed had the highest PM2.5 concentration,cave dwelling in which clean energy were consumed had the lowest PM2.5 concentration.Compared with traditional solid fuels,using clean energy could reduce the PM2.5concentration in the cave dwelling by more than 21%.Temperature and relative humidity are significantly linearly related to the indoor and outdoor PM2.5,and there were different between indoor and outdoor,which was mainly related to whether solid fuel is used indoors.?2?Resident's PM2.5 exposure in cave dwelling and its health effects:The average daily concentration of PM2.5 exposure was 191±70?g/m,and the average systolic blood pressure?SBP?of the residents in cave dwelling was 133±16 mm Hg.Both of them were significantly higher than that of the urban residents in the area.The PM2.5exposure concentration and systolic pressure of cave dwelling residents were influenced by the type of fuel.Using clean energy such as electricity and liquefied petroleum gas could reduce the PM2.5 exposure concentration and systolic pressure of residents in cave dwelling by 21%and 3.7%,respectively.The relative risk of acute lower respiratory infection,lung cancer,ischemic heart disease,stroke,and chronic obstructive pulmonary disease were relatively higher,which were 2.27,1.66,1.53,1.98and 1.46 respectively.For the population attributable fraction of different diseases in the study area,they were 0.655?0.582?0.503?0.476 and 0.403,respectively.Compared with the national average PAFs,the residents in cave dwelling had higher ALRI and STROKE PAFs,they should pay more attention to ALRI and STROKE.Besides,systolic blood pressure?SBP?was demonstrated to be positively associated with personal PM2.5 exposure,and affected by age:with each 10-?g/m3 incremental PM2.5concentration when controlling all the other factors,SBP will increase by 0.46 mm Hg?95%confident interval?CI?:0.0036-0.92 mm Hg?In conclusion,this study indicated that both ndoor and outdoor PM2.5 pollution in cave dwelling were serious,and the indoor concentration is significantly higher than outdoor.Cooking,heating,fuel types,and meteorological conditions all had a significant impact on the indoor and outdoor PM2.5pollution in the cave dwelling.Useing clean energy could reduce the indoor PM2.5 concentration and resident's PM2.5exposure in the cave dwelling significantly.Residents in cave dwelling had great health risk with relatively high PM2.5 exposure,including higher systolic blood pressure and higher relative risks and population attribution scores for various diseases.This study revealed the characteristics of indoor and outdoor PM2.5 in cave swelling and their possible health effects,provided a systematic assessment of PM2.5 and its health effects,and provided support for the scientific prevention and control of air pollution and related diseases. |
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