A tracer element can help distinguish between indoor PM2.5 of outdoor origin and that of indoor origin. PM2.5-associated iron has been proposed as a tracer element of PM2.5 in Beijing. This study aims to examine the effect of particulate iron on tracking indoor PM2.5 of outdoor origin in temporal and spatial scales. From July 2018 to March 2019, we collected 24 pairs of indoor and outdoor PM2.5 samples in Nanjing, China. We calculated a normalized ratio (ratio of indoor/outdoor (I/O) ratio of iron to that of PM2.5). Results show a mean ± SD of the normalized ratio of 1.0 ± 0.38. It suggests that particulate iron tracks PM2.5 well during outdoor-to-indoor transport on average. This tracking performance varies temporally. The mean ± SD of the normalized ratio is 0.79 ± 0.17 from July to December 2018 and 1.2 ± 0.41 in March. The results from studies published in different regions of the world over recent years show a mean normalized ratio of 0.88, 0.67, 1.3 and 0.8 in Asia, Europe, North America and South America, respectively, indicating the spatial heterogeneity of iron’s tracking effect. In comparison, sulphate appears to exhibit a less stable tracking effect than iron.
van DonkelaarAMartinRVBrauerMKahnRLevyRVerduzcoCVilleneuvePJ.Global estimates of ambient fine particulate matter concentrations from satellite-based aerosol optical depth: development and application. Environ Health Perspect2010;
118: 847–855.
2.
YouSMWanMP.Experimental investigation and modelling of human-walking-induced particle resuspension. Indoor Built Environ2015;
24: 564–576.
3.
EmbialeAZewgeFChandravanshiBSSahle-DemessieE.Short-term exposure assessment to particulate matter and total volatile organic compounds in indoor air during cooking Ethiopian sauces (Wot) using electricity, kerosene and charcoal fuels. Indoor Built Environ2019;
28: 1140–1154.
4.
ZwozdziakASowkaIWorobiecAZwozdziakJNychA.The contribution of outdoor particulate matter (PM1, PM2.5, PM10) to school indoor environment. Indoor Built Environ2015;
24: 1038–1047.
5.
LiuCWangHXGuoHY.Redistribution of PM2.5-associated nitrate and ammonium during outdoor-to-indoor transport. Indoor Air2019;
29: 460–468.
6.
PopeCADockeryDW.Health effects of fine particulate air pollution: lines that connect. J Air Waste Manag Assoc2006;
56: 709–742.
7.
BrookRDRajagopalanSPopeCABrookJRBhatnagarADiez-RouxAVHolguinFHongYLLuepkerRVMittlemanMAPetersASiscovickDSmithSCWhitselLKaufmanJD.Particulate matter air pollution and cardiovascular disease: an update to the scientific statement from the American Heart Association. Circulation2010;
121: 2331–2378.
8.
YangYRuanZLWangXJYangYMasonTGLinHLTianLW.Short-term and long-term exposures to fine particulate matter constituents and health: a systematic review and meta-analysis. Environ Pollut2019;
247: 874–882.
9.
LiuQBWangWJingW.Indoor air pollution aggravates asthma in Chinese children and induces the changes in serum level of miR-155. Int J Environ Health Res2019;
29: 22–30.
10.
FengBHLiLJXuHBWangTWuRSChenJZhangYLiuSHoSSHCaoJJHuangW.PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Beijing: seasonal variations, sources, and risk assessment. J Environ Sci (China)2019;
77: 11–19.
11.
ShuklaABunkarNKumarRBhargavaATiwariRChaudhuryKGoryachevaIYMishraPK.Air pollution associated epigenetic modifications: transgenerational inheritance and underlying molecular mechanisms. Sci Total Environ2019;
656: 760–770.
12.
KlepeisNENelsonWCOttWRRobinsonJPTsangAMSwitzerPBeharJVHernSCEngelmannWH.The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. J Expo Anal Environ Epidemiol2001;
11: 231–252.
13.
ChenCZhaoB.Review of relationship between indoor and outdoor particles: I/O ratio, infiltration factor and penetration factor. Atmos Environ2011;
45: 275–288.
14.
DengGFLiZHWangZCGaoJBXuZWLiJDWangZY.Indoor/outdoor relationship of PM2.5 concentration in typical buildings with and without air cleaning in Beijing. Indoor Built Environ2017;
26: 60–68.
15.
LiuCShiSSWeschlerCZhaoBZhangYP.Analysis of the dynamic interaction between SVOCs and airborne particles. Aerosol Sci Tech2013;
47: 125–136.
16.
TianEZMoJH.Toward energy saving and high efficiency through an optimized use of a PET coarse filter: the development of a new electrostatically assisted air filter. Energ Build2019;
186: 276–283.
17.
TianEZMoJHLongZWLuoHYZhangYP.Experimental study of a compact electrostatically assisted air coarse filter for efficient particle removal: synergistic particle charging and filter polarizing. Build Environ2018;
135: 153–161.
18.
LiuCZhaoBZhangYP.The influence of aerosol dynamics on indoor exposure to airborne DEHP. Atmos Environ2010;
44: 1952–1959.
19.
SarnatJALongCMKoutrakisPCoullBASchwartzJSuhHH.Using sulfur as a tracer of outdoor fine particulate matter. Environ Sci Technol2002;
36: 5305–5314.
20.
LiuCZhangYP.Relations between indoor and outdoor PM2.5 and constituent concentrations. Front Env Sci Eng2019;
13: 5.
21.
AllenRWAdarSDAvolECohenMCurlCLLarsonTLiuLJSSheppardLKaufmanJD.Modeling the residential infiltration of outdoor PM2.5 in the multi-ethnic study of atherosclerosis and air pollution (MESA air). Environ Health Perspect2012;
120: 824–830.
22.
CohenMAAdarSDAllenRWAvolECurlCLGouldTHardieDHoAKinneyPLarsonTVSampsonPSheppardLStukovskyKDSwanSSLiuLJSKaufmanJD.Approach to estimating participant pollutant exposures in the multi-ethnic study of atherosclerosis and air pollution (MESA air). Environ Sci Technol2009;
43: 4687–4693.
23.
MengQYTurpinBJPolidoriALeeJHWeiselCMorandiMColomeSStockTWinerAZhangJF.PM2.5 of ambient origin: estimates and exposure errors relevant to PM epidemiology. Environ Sci Technol2005;
39: 5105–5112.
24.
WallaceLWilliamsR.Use of personal-indoor-outdoor sulfur concentrations to estimate the infiltration factor and outdoor exposure factor for individual homes and persons. Environ Sci Technol2005;
39: 1707–1714.
25.
JiWJLiHYZhaoBDengFR.Tracer element for indoor PM2.5 in China migrated from outdoor. Atmos Environ2018;
176: 171–178.
SaragaDMaggosTSadounEFthenouEHassanHTsiouriVKaravoltsosSSakellariAVasilakosCKakosimosK.Chemical characterization of indoor and outdoor particulate matter (PM2.5, PM10) in Doha, Qatar. Aerosol Air Qual Res2017;
17: 1156–1168.
28.
ZhangJMChenJMYangLXSuiXYaoLZhengLFWenLXuCHWangWX.Indoor PM2.5 and its chemical composition during a heavy haze-fog episode at Jinan, China. Atmos Environ2014;
99: 641–649.
29.
ChithraVSNagendraS.Chemical and morphological characteristics of indoor and outdoor particulate matter in an urban environment. Atmos Environ2013;
77: 579–587.
30.
LomboyMQuiritLLMolinaVBDalmacionGVSchwartzJDSuhHHBajaES.Characterization of particulate matter 2.5 in an urban tertiary care hospital in the Philippines. Build Environ2015;
92: 432–439.
31.
YangYBLiuLXuCYLiNLiuZWangQXuDQ.Source apportionment and influencing factor analysis of residential indoor PM2.5 in Beijing. Int J Env Res Pub He2018;
15: 686.
32.
ZhuCSCaoJJShenZXLiuSXZhangTZhaoZZXuHMZhangEK.Indoor and outdoor chemical components of PM2.5 in the rural areas of Northwestern China. Aerosol Air Qual Res2012;
12: 1157–1165.
33.
RivasIVianaMMorenoTBousoLPandolfiMAlvarez-PedrerolMFornsJAlastueyASunyerJQuerolX.Outdoor infiltration and indoor contribution of UFP and BC, OC, secondary inorganic ions and metals in PM2.5 in schools. Atmos Environ2015;
106: 129–138.
34.
VianaMRivasIQuerolXAlastueyASunyerJÁlvarez-PedrerolMBousoLSioutasC.Indoor/outdoor relationships and mass closure of quasi-ultrafine, accumulation and coarse particles in Barcelona schools. Atmos Chem Phys2014;
14: 4459–4472.
35.
MorenoTRivasIBousoLVianaMJonesTAlvarez-PedrerolMAlastueyASunyerJQuerolX.Variations in school playground and classroom atmospheric particulate chemistry. Atmos Environ2014;
91: 162–171.
36.
LoupaGZarogianniAMKaraliDKosmadakisIRapsomanikisS.Indoor/outdoor PM2.5 elemental composition and organic fraction medications, in a Greek hospital. Sci Total Environ2016;
550: 727–735.
37.
SajaniSZRicciardelliITrentiniABaccoDMacconeCCastellazziSLauriolaPPoluzziVHarrisonRM.Spatial and indoor/outdoor gradients in urban concentrations of ultrafine particles and PM2.5 mass and chemical components. Atmos Environ2015;
103: 307–320.
38.
PerrinoCToffulLCanepariS.Chemical characterization of indoor and outdoor fine particulate matter in an occupied apartment in Rome, Italy. Indoor Air2016;
26: 558–570.
39.
MontagneDHoekGNieuwenhuijsenMLankiTPennanenAPortellaMMeliefsteKWangMEeftensMYli-TuomiTCirachMBrunekreefB.The association of LUR modeled PM2.5 elemental composition with personal exposure. Sci Total Environ2014;
493: 298–306.
40.
MontagneDHoekGNieuwenhuijsenMLankiTSiponenTPortellaMMeliefsteKBrunekreefB.Temporal associations of ambient PM2.5 elemental concentrations with indoor and personal concentrations. Atmos Environ2014;
86: 203–211.
41.
HuangSDLawrenceJKangCMLiJMartinsMVokonasPGoldDRSchwartzJCoullBAKoutrakisP.Road proximity influences indoor exposures to ambient fine particle mass and components. Environ Pollut2018;
243: 978–987.
42.
JohnKKarnaeSCristKKimMKulkarniA.Analysis of trace elements and ions in ambient fine particulate matter at three elementary schools in Ohio. J Air Waste Manag Assoc2007;
57: 394–406.
43.
HasheminassabSDaherNShaferMMSchauerJJDelfinoRJSioutasC.Chemical characterization and source apportionment of indoor and outdoor fine particulate matter (PM2.5) in retirement communities of the Los Angeles Basin. Sci Total Environ2014;
490: 528–537.
44.
StevensCWilliamsRJonesP.Progress on understanding spatial and temporal variability of PM2.5 and its components in the Detroit Exposure and Aerosol Research Study (DEARS). Environ Sci Process Impacts2014;
16: 94–105.
45.
BaxterLKCloughertyJELadenFLevyJI.Predictors of concentrations of nitrogen dioxide, fine particulate matter, and particle constituents inside of lower socioeconomic status urban homes. J Expo Sci Environ Epidemiol2007;
17: 433–444.
46.
MonsalveSMMartinezLVasquezKYOrellanaSAVergaraJKMateoMMSalazarRCAlburquenqueMFLilloD.Trace element contents in fine particulate matter (PM2.5) in urban school microenvironments near a contaminated beach with mine tailings, Chaaral, Chile. Environ Geochem Health2018;
40: 1077–1091.
47.
BarrazaFJorqueraHValdiviaGMontoyaLD.Indoor PM2.5 in Santiago, Chile, spring 2012: source apportionment and outdoor contributions. Atmos Environ2014;
94: 692–700.
48.
RuizPAToroCCáceresJLópezGOyolaPKoutrakisP.Effect of gas and kerosene space heaters on indoor air quality: a study in homes of Santiago, Chile. J Air Waste Manag Assoc2010;
60: 98–108.
49.
LiuCMorrisonGCZhangYP.Role of aerosols in enhancing SVOC flux between air and indoor surfaces and its influence on exposure. Atmos Environ2012;
55: 347–356.
50.
LiuCYangJYJiSYLuYXWuPCChenC.Influence of natural ventilation rate on indoor PM2.5 deposition. Build Environ2018;
144: 357–364.
51.
CaoSJRenC.Ventilation control strategy using low-dimensional linear ventilation models and artificial neural network. Build Environ2018;
144: 316–333.
52.
CaoSJ.Challenges of using CFD simulation for the design and online control of ventilation systems. Indoor Built Environ2019;
28: 3–6.
