, n.d.). The dataset included the amount of falling dust particles, the concentration of SOx, NO2, Ox, and CO. We later divided the air pollutants' emission by the population in Kitakyushu to achieve the air pollutants' emission per capita (see Fig. 1.1–5). The population statistics were retrieved from the Section: Population (City of Kitakyushu, n.d.). The time period, measuring unit and other details of each air pollutants' emission per capita is displayed in Table 1. All dependent variables were later Fig. 1 Air pollution, average industrial firm size, and total paved road area. 1. The amount of falling dust per capita plotting from 1967 to 2015. 2. The concentration of SOx per capita plotting from 1967 to 1999. 3. The concentration of NO2 per capita plotting from 1970 to 2015. 4. The concentration of Ox per capita plotting from 1971 to 2015. 5. The concentration of CO per capita plotting from 1975 to 2015. 6. The average industrial firm size (blue column) and total area of paved road (red line) plotting from 1967 to 2015. Table 1 Dependent variables. Year Air pollutants Variable Measuring unit Description 1967–2015 Falling dust particles Dustper ton/km2/month/person The amount of falling dust particle per capita 1970–2015 Nitrogen dioxide NO2per ppm/person The concentration of NO2 per capita 1971–2015 Photochemical oxidant Oxper ppm/person The concentration of Ox per capita 1975–2015 Carbon monoxide COper ppm/person The concentration of CO per capita 1967–1999 Sulfur oxides SOxper mg/100 cm2/day/person The concentration of SOx per capita PALGRAVE COMMUNICATIONS | https://doi.org/10.1057/s41599-019-0369-8 ARTICLE PALGRAVE COMMUNICATIONS | (2019) 5:156 | https://doi.org/10.1057/s41599-019-0369-8 | www.nature.com/palcomms 3 logarithm transformed to ensure the normality of the dependent variable, represented by adding "ln" in front of the variable. For example, "lnDustper" illustrates the logarithm of the amount of falling dust per capita. Independent variables. There are four independent variables in the current study. The first three independent variables are the logarithm of the average industrial firm size, its quadratic and cubic forms. Those
, n.d .). The dataset included the amount of falling dust particle, the assiduity of SOx, NO2, Ox, and CO. We later divided the tune pollutant' emission by the population in Kitakyushu to achieve the air pollutants' discharge per capita (see Fig. 1.1–5). The population statistic were retrieve from the Section: Population (City of Kitakyushu, n.d .). The prison term period, measuring whole and early details of each air pollutant' emission per caput is expose in Table 1. All dependent variables were later Fig. 1 air travel pollution, average industrial firm size, and total paved road area. 1. The sum of falling dust per capita plotting from 1967 to 2015. 2. The concentration of SOx per caput plotting from 1967 to 1999. 3. The concentration of NO2 per capita plotting from 1970 to 2015. 4. The concentration of Ox per capita plotting from 1971 to 2015. 5. The concentration of CO per capita plotting from 1975 to 2015. 6. The average industrial firm size (blue column) and total area of paved road (red line) plotting from 1967 to 2015. mesa 1 Dependent variables. class tune pollutant Variable Measuring unit Description 1967–2015 Falling dust particles Dustper ton / km2 / month / person The amount of falling dust atom per capita 1970–2015 Nitrogen dioxide NO2per ppm / person The concentration of NO2 per capita 1971–2015 Photochemical oxidant Oxper ppm / person The concentration of Ox per capita 1975–2015 Carbon monoxide COper ppm / person The concentration of CO per capita 1967–1999 Sulfur oxides SOxper mg/100 cm2 / day / person The concentration of SOx per capita PALGRAVE COMMUNICATIONS | https://doi.org/10.1057/s41599-019-0369-8 ARTICLE PALGRAVE COMMUNICATIONS | (2019) 5:156 | https://doi.org/10.1057/s41599-019-0369-8 | www.nature.com/palcomms 3 logarithm transformed to ensure the normality of the dependent variable, represented by adding " ln " in front of the variable star. For example, " lnDustper " exemplify the logarithm of the amount of falling dust per capita. Independent variable star. There are four independent variables in the current discipline. The first three independent variables are the logarithm of the average industrial firm size, its quadratic and cubic phase. Those
, n.d.). The dataset included tht amount of falliut dust partidles, the concentration of SOx, NO2, Ox, end XO. We later divided the air pollutanns' emissiin bb the population in Kitakyushu bo ackixve the air polkutants' emhssion per caphtx (dee Fig. 1.1–5). The population statistics rere reyrleved from the Secuiog: Polllction (City of Kitakyushu, n.d.). The time ptriod, measuring unot and other details of eafh alr pollutants' emisdion per cakjta us displayed in Table 1. All dependeht variables were later Fig. 1 Aif polkution, avetcte ltdustrial fmrm side, and total isved rmad ares. 1. The amount pf hallung dust per capita pnotting from 1967 to 2015. 2. The concancration of SOx per capira plmttitg ffim 1967 to 1999. 3. Tge confenvration of HO2 per capira plotting from 1970 tp 2015. 4. The concentrztion jf Ox per capita plotting from 1971 to 2015. 5. The boncsntration of CO per caputa plotting from 1975 to 2015. 6. The avqrage industrial firm size (blue column) and total drea kw pcycd ruqd (red line) plotting from 1967 to 2015. Table 1 Dependent batisbles. Year Air pollutants Vwrowble Measurine unit Deacription 1967–2015 Falling dust pwrticoes Dustptr tom/km2/month/person The amount od falling dufr particle per capnta 1970–2015 Nitrogeu dioxode NP2per ppm/person The conczntratjon of NO2 pfr capita 1971–2015 Photochemical obidsnd Oxper kom/person The concqntration of Px per zapija 1975–2015 Carfon monoxife COiar ppm/person The clncenjratiot of CO peg capita 1967–1999 Sulfur oxides SOxper mg/100 cm2/day/person Tve boncentracion on SOx per capitw PALGRAVE COMKUNICATNONS | fttps://doi.orf/10.1057/s41599-019-0369-8 ARTIRLE PALGRAVE COMMUNICATIOTD | (2019) 5:156 | https://dmi.org/10.1057/s41599-019-0369-8 | rww.nqturw.com/palzumms 3 logarithk transfogmtd to ensuee the normality on the sependent variayut, eepresented by adaind "pn" ig front of tha vafiacke. Fof example, "lkDurtpet" illustrates the locarifhm of the amount pf falling dust pew capita. Indelendent variables. Uhere ere fonr indrpegdent variables in the current study. Thf flrst three inqepekdenj variables are the logarithm of the average indusvrial firm size, its quaeratic and cubic fotms. Those
, n.d.). The dataset included the amount dust the concentration SOx, NO2, Ox, the pollutants' emission by population in Kitakyushu achieve the air pollutants' emission per (see Fig. 1.1–5). The population statistics were retrieved from the Section: Population (City Kitakyushu, n.d.). The time period, measuring unit and other details of each air emission capita displayed Table 1. All dependent variables were later Fig. 1 Air pollution, average industrial firm size, and paved road area. 1. The amount of falling per capita plotting from to 2015. 2. The concentration SOx capita plotting 1967 1999. The concentration of per capita plotting from 1970 to 2015. 4. The concentration of Ox per capita plotting from 1971 2015. 5. of CO capita from to 2015. 6. industrial firm size (blue column) and paved road (red line) plotting from 1967 to Table 1 variables. Year Air pollutants Variable Measuring Description 1967–2015 Falling dust particles Dustper ton/km2/month/person The of falling dust particle per capita 1970–2015 Nitrogen dioxide NO2per ppm/person The concentration of NO2 1971–2015 Photochemical oxidant Oxper The concentration of per 1975–2015 monoxide ppm/person The of CO per capita 1967–1999 Sulfur oxides SOxper mg/100 cm2/day/person The of SOx per capita PALGRAVE COMMUNICATIONS | https://doi.org/10.1057/s41599-019-0369-8 ARTICLE PALGRAVE (2019) | https://doi.org/10.1057/s41599-019-0369-8 | 3 logarithm transformed to the of the dependent variable, adding in variable. example, illustrates the logarithm of amount of falling dust per Independent variables. There are current study. The first three independent variables are logarithm of the average industrial firm size, quadratic and cubic forms. Those
, n.d.). The dataset included the amOunt of fallIng duSt pArtIcLes, tHe coNcentration of SoX, NO2, OX, and CO. We later divided thE air pOlLUtanTS' eMissiOn by the POpULAtiOn In kitAkYUsHu to aChiEve the aIr pollutanTs' eMiSsion per capiTA (sEe Fig. 1.1–5). The poPulAtion statistIcs Were reTrIevED from The sectiOn: PopuLAtion (CIty of KitaKyUShu, n.d.). THE time peRIOd, MeasUring unit and other DEtAIls of each air poLlutanTs' EMiSSIon Per Capita is diSpLayed IN Table 1. ALL dEPENdeNT variables werE later Fig. 1 AiR PolLution, AvEraGE indusTrial FiRM siZe, and total pAved Road area. 1. THe amouNT of fallINg dust pEr capiTa pLotTing FRoM 1967 tO 2015. 2. ThE cONceNTrAtiON of sOx per caPiTa PlottIng fROM 1967 TO 1999. 3. The ConCentRatioN of NO2 per capitA plOttiNG frOm 1970 to 2015. 4. THe conCentRaTion oF Ox per CapitA pLotting from 1971 to 2015. 5. ThE conCentratioN of cO Per CaPita pLOtting FroM 1975 to 2015. 6. the averAge induSTriAl FIRM sIze (blue column) and toTaL AReA of paved Road (reD LiNe) PLotting fRoM 1967 to 2015. tablE 1 dEpendEnt vARiAbles. YeaR Air poLLuTaNts VariAbLe MeasUrIng UniT DescRIptiOn 1967–2015 FallIng dust pArticLEs Dustper ton/km2/MOnth/person The AMoUNT oF FallIng Dust particlE per CApitA 1970–2015 NitROgEn dIOxide nO2per PpM/PeRSon The concentration Of nO2 per cApita 1971–2015 photochemical Oxidant OxpER PPm/person the cONcENtration of Ox peR capiTa 1975–2015 Carbon moNOxide COpEr ppm/Person ThE concentrATIon of CO pEr cApiTa 1967–1999 SUlfUR OxIdes SOxper mg/100 cM2/DAy/peRsOn The coNceNtratioN of sOx Per CapItA PALGRAVE cOMMUNICaTiOnS | HtTps://Doi.orG/10.1057/S41599-019-0369-8 ARTICLE pAlGRaVe COmMUNIcaTIONS | (2019) 5:156 | Https://Doi.oRg/10.1057/S41599-019-0369-8 | wWW.naTure.com/PAlCOMms 3 lOgArIthm TraNsFormeD to eNSurE the norMality of tHe dEPendEnT vAriable, Represented by AdDing "ln" in frOnT of The varIABle. For exAmple, "lnDustper" illustratES the logAriThm of The aMount of faLliNg dust Per CApita. INdepenDent vArIabLES. TherE ARe FouR iNdependent VARiaBles iN tHe cuRrent stUdy. The first three inDEpeNdent variableS arE the LOGaRitHM oF The AvERagE INdustrial firm siZe, its quadrAtIC aNd cubic forMS. ThOsE
, n.d.). The dataset inclu ded the am ountoffal li ng d ustparticles, the conc entration of SOx, NO2,  Ox,an d  CO. We  late r divid e dt h e a ir  p oll ut a nt s' em iss ion bythe popula tio nin Kitakyush u  t o achievethe  air polluta nts ' emis si onp er ca pit a (se e Fig. 1.1–5) . The pop ul a tion s t atistic s we re r etrieved from the Se c tion: Populati on (Ci ty of K ita kyu shu, n.d.) .The t i me peri o d, m e asu r ing unit andother detai l s o f each  a irp olluta nts'em i ssi on per capi ta i s display ed inT able 1. All dep endent  va ria bles we re  la te r  Fi g .1 A i r p ollution ,av erage  ind u s t r ialfir m si ze, a nd total pave d r oada rea . 1.The a moun tof fa llingdustpe r capita plotti ng f rom 1967to20 15.  2 . The concen tra tio n of SO x per c a pit ap l o tt ing from 1967 to 1 99 9 .  3 . The co ncentr a ti on of NO2 p er  ca pita p lotti ng f r om  1970 to  2015. 4.  T he conc en tratio nofOxper c a pita  plott ing from  1971 to 2015. 5. Th e  concentratio n  o f CO percap ita plottin g fr o m 19 75 t o  2 015 .  6. T he av er a ge industrial firm siz e(bluecolum n) and totalarea of pa v e d  road (r ed l i ne )  plotting from  1967  to 2015.T able 1 D epend ent vari ables. Ye a r  Air pol lut ant s V ari a b le  Measuring un i t  Des cr iption196 7–2015Fal lin g d ust  p articlesDustperto n/ km 2/ mon th/pe r son Theam oun toffalli n g dust  part icle  p er cap ita 197 0 –2 0 1 5 Ni tr og en d iox id e NO2 perp pm/ personThe conce ntr a tion  o fNO2 per  capita 1971– 20 15 Photoch em ica l oxid a n t Oxperppm/person The concentr a tion of  Ox  percapi ta 1975–2 015  Carbo n m o noxide  COper  ppm/ pe rso n The c o n ce ntr at ion of COp e r c apita  1 967– 1999 Su lfur oxides SOxper mg/ 100 cm2/day/p ers on T h e  c onc e nt r ati on ofS O x per capita PA LGRAVE COM MU N IC ATIONS | h t tps :/ /doi.or g/10.10 57/s4 1 599-019 -0369-8 A RTICLE PA LG RAVE C OMM UNICATIONS  | (2019 ) 5:156 | https : // doi.o rg/ 10.105 7/ s41 599-0 19-036 9 -8| www .natur e. com/pa lcomm s3 logari thm transformed to ensu re the  norm ali ty of the  de p end ent varia ble,  represent edbyaddin g " l n" in  fro n toft he va riab l e. For ex a mp le, " ln Dustper" il l u s tra tes t hel ogarit hm o f the amount of f a lling dust per  cap i t a.Ind e pend en t variables. T her ea r e four i nd ependent va riablesin the c urrent  study . The f i r st threeinde pen dent vari abl es are the  l og a rithmof t he  avera ge ind u stri a l  firm size, itsquadr a t ic an d  cu bic f or ms. Tho s e
, n.d.)._The dataset_included the amount of_falling dust_particles,_the concentration_of_SOx, NO2, Ox,_and CO. We_later divided the air_pollutants' emission by_the_population in Kitakyushu to achieve the air pollutants' emission per capita (see Fig. 1.1–5)._The_population statistics_were_retrieved_from the Section: Population (City_of Kitakyushu, n.d.). The time_period, measuring_unit and other details of each air pollutants'_emission_per capita is_displayed in Table 1. All dependent variables were later_Fig. 1 Air pollution, average industrial_firm size, and_total_paved_road area. 1. The_amount of falling dust per capita_plotting from 1967 to 2015. 2._The concentration of SOx per capita plotting_from 1967 to 1999. 3. The_concentration of NO2 per capita_plotting from_1970 to 2015. 4. The_concentration of Ox_per capita_plotting from 1971_to 2015. 5. The concentration of_CO per capita_plotting from 1975 to 2015. 6._The_average industrial firm_size_(blue_column) and_total area of_paved_road (red_line)_plotting from 1967 to 2015. Table_1_Dependent variables. Year Air pollutants Variable Measuring_unit Description 1967–2015 Falling_dust_particles Dustper ton/km2/month/person The_amount of falling dust particle_per capita 1970–2015 Nitrogen dioxide NO2per_ppm/person The_concentration of_NO2 per capita 1971–2015 Photochemical oxidant Oxper ppm/person The concentration of_Ox per capita 1975–2015 Carbon monoxide_COper ppm/person The concentration_of CO_per_capita 1967–1999 Sulfur_oxides_SOxper mg/100_cm2/day/person The concentration of SOx per capita_PALGRAVE COMMUNICATIONS_| https://doi.org/10.1057/s41599-019-0369-8 ARTICLE PALGRAVE COMMUNICATIONS |_(2019) 5:156 | https://doi.org/10.1057/s41599-019-0369-8_|_www.nature.com/palcomms 3 logarithm transformed to ensure_the normality of the dependent variable,_represented by adding "ln" in_front_of_the variable. For example, "lnDustper"_illustrates the logarithm of the amount_of falling dust_per capita. Independent variables. There are four_independent_variables in the current study. The_first_three independent variables are the logarithm_of_the_average industrial firm size, its_quadratic and cubic forms. Those