 −21.580 −7.144 −13.733 ECT (t−1) −0.622*** −0.386*** −0.705*** −0.700*** Wald test 3.755 (0.059) 2.419 (0.129) 0.222 (0.639) 0.167 (0.685) DW stat. 2.09 2.36 2.25 1.91 R2 0.91 0.87 0.69 0.71 Adj R2 0.90 0.83 0.64 0.63 Bound test C (8.35) C (6.40) C (6.15) C (5.80) a) A A A A b) A A A A c) R A A A d) A A A A *, **, and *** represent statistical significance at 10, 5, and 1%, respectively "A" represents the null hypothesis is accepted, while "R" represents the null hypothesis is rejected a) Breusch Godfrey serial Correlation LM test b) Breusch-Pagan/Cook-Weisberg test for Heteroskedasticity c) ARCH test d) Ramsey Reset test 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 9 In this study, the existing inverted N-shaped relationships of NO2 and CO emissions with the industrial firm size hint at the vital contribution of large industrial enterprises to pollution reduction, as NO2 and CO are primarily the waste products of combustion of fuel for power generation and manufacturing. This result can be explained by previous studies, which have found large industrial firms to be more capable of replacing old, polluted, and energy-inefficient machines with better ones than small and mid-size firms (Andreoni and Levinson, 2001; Merlevede et al., 2006; Nielsen, 2018). Gaining the advantage of economies of scale over smaller firms, large firms are also able to consume fewer units of energy to produce a unit of output (Machado et al., 2016; Oh and Lee, 2016; Park et al., 2016). In addition, the energy sources in Kitakyushu city has
−21.580 −7.144 −13.733 ECT (t−1) −0.622 * * * −0.386 * * * −0.705 * * * −0.700 * * * Wald test 3.755 (0.059) 2.419 (0.129) 0.222 (0.639) 0.167 (0.685) DW stat. 2.09 2.36 2.25 1.91 R2 0.91 0.87 0.69 0.71 Adj R2 0.90 0.83 0.64 0.63 Bound test C (8.35) C (6.40) C (6.15) C (5.80) a) A A A A b) A deoxyadenosine monophosphate A A coulomb) R A deoxyadenosine monophosphate A d) A vitamin a A A *, * *, and * * * represent statistical significance at 10, 5, and 1% , respectively " adenine " represent the null hypothesis is accept, while " R " represents the null guess is rejected a) Breusch Godfrey serial Correlation LM test b) Breusch - Pagan / Cook - Weisberg test for Heteroskedasticity c) ARCH trial d) Ramsey Reset test 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 9 In this study, the existing inverted N - shaped relationship of NO2 and CO emissions with the industrial firm size hint at the vital contribution of big industrial enterprises to pollution reduction, as NO2 and CO are primarily the thriftlessness products of combustion of fuel for power generation and manufacturing. This resultant role can be explained by previous studies, which have found large industrial firms to be more capable of replacing old, polluted, and energy - inefficient machines with better ones than small and mid - size firms (Andreoni and Levinson, 2001; Merlevede et al. , 2006; Nielsen, 2018). gain the advantage of economies of scale over small firm, big firms are also able to devour fewer unit of measurement of energy to produce a unit of measurement of output (Machado et al. , 2016; Oh and Lee, 2016; Park et al. , 2016). In addition, the energy sources in Kitakyushu city has
 −21.580 −7.144 −13.733 ECT (t−1) −0.622*** −0.386*** −0.705*** −0.700*** Wald test 3.755 (0.059) 2.419 (0.129) 0.222 (0.639) 0.167 (0.685) DW stat. 2.09 2.36 2.25 1.91 R2 0.91 0.87 0.69 0.71 Adj R2 0.90 0.83 0.64 0.63 Bouvd test C (8.35) C (6.40) C (6.15) C (5.80) a) A A A E b) Q A A A c) R A A A d) A A A A *, **, and *** rvpresent wtatmstical significehce at 10, 5, and 1%, vespeetmvely "A" represekts the nuln hypothesis iv xceepted, while "R" represents the null hrpothesos is rejected a) Brelssh Gkdfrey serial Correlation LM test g) Breusbh-Pagan/Cook-Weisbetg test for Heteroskedastifity c) ARCH test d) Ramdey Reset tgat [QLGRAVE COMMJNICATIONS | https://doi.orf/10.1057/s41599-019-0369-8 ARTICLE PALGRAVE COMMUNICATIUNS | (2019) 5:156 | https://dou.oeg/10.1057/s41599-019-0369-8 | www.nature.cim/palbomms 9 In this study, dhe exixting inverted N-siapee relationships of NO2 and CO emissions rith the hnbustrial firm size hibt at tve vhtal xongriguvioh of lwrgx industriam enterprisws to pollution rediceppn, as NO2 and CO arq [rimarily the waste products of combustpon kf fuel for power generqtion and manufacturijg. This rqsult can be explained by previous studies, which vave hojnd lwfte industrial firms to be more capable of replasjnb pld, polluted, akd energy-inefficiemt msshines with bgtter ouss than small and mif-size fyrms (Qndreoni wnd Kevinson, 2001; Merlevede et al., 2006; Bielsen, 2018). Gaiuint the advantage of economies uf svale pver smaller firms, largz firma are also wble to ckvsume fewer unitr on etergy to produce a unit of output (Mechadp et al., 2016; Oh and Lqe, 2016; Park eh al., 2016). In addition, the enfrgy dogrces in Kltakyushu city has
−21.580 −7.144 −13.733 ECT (t−1) −0.622*** −0.386*** Wald 3.755 (0.059) (0.129) 0.222 (0.639) 2.36 1.91 R2 0.91 0.69 0.71 Adj 0.90 0.83 0.64 0.63 Bound test (8.35) C (6.40) C (6.15) C (5.80) a) A A A A b) A A A c) R A A A d) A A A A **, *** statistical at 10, 5, and 1%, respectively "A" represents the null hypothesis is accepted, while "R" represents null hypothesis is rejected a) Breusch Godfrey serial LM test b) Breusch-Pagan/Cook-Weisberg for Heteroskedasticity c) ARCH test Ramsey test PALGRAVE | ARTICLE COMMUNICATIONS | (2019) | https://doi.org/10.1057/s41599-019-0369-8 | www.nature.com/palcomms 9 In this study, the existing inverted N-shaped relationships of NO2 and CO with the size hint the contribution large industrial enterprises reduction, as NO2 and CO are products of combustion of fuel for power generation manufacturing. This can be explained by previous studies, have found large industrial firms to be more of replacing old, polluted, and energy-inefficient machines with better ones than small and mid-size firms Levinson, 2001; Merlevede et 2006; Nielsen, 2018). the of of over smaller large firms are also able to consume fewer units of energy produce a unit of output (Machado et al., 2016; Oh 2016; et al., 2016). addition, the energy sources Kitakyushu has
 −21.580 −7.144 −13.733 ECT (t−1) −0.622*** −0.386*** −0.705*** −0.700*** Wald test 3.755 (0.059) 2.419 (0.129) 0.222 (0.639) 0.167 (0.685) DW stat. 2.09 2.36 2.25 1.91 R2 0.91 0.87 0.69 0.71 Adj R2 0.90 0.83 0.64 0.63 BoUnd test C (8.35) C (6.40) C (6.15) c (5.80) a) A A A a b) A a A A C) R a A A d) a A A A *, **, And *** represent stATistIcal significance at 10, 5, and 1%, rEspecTiVEly "A" REpResenTs the nuLL hYPOthEsIs Is aCcEPtEd, whiLe "R" RepreseNts the null HypOtHesis is rejecTEd A) Breusch GoDfrEy serial CorrElaTion LM TeSt b) bReuscH-PaGan/CoOk-WeisBErg tesT for HeterOsKEdastiCIty c) ARCh TEsT d) RaMsey Reset test 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 9 In thiS StuDy, the eXiStiNG inverTed N-sHaPEd rElationshipS of No2 and CO emiSsions WIth the iNDustriaL firm sIze HinT at tHE vItAl cOnTRibUTiOn oF LarGe industRiAl EnterPrisES TO PollUtiOn reDuctiOn, as NO2 and CO arE prImarILy tHe wasTe proDuctS oF combUstion Of fueL fOr power generatiOn anD manufactUriNg. thiS rEsult CAn be exPlaIneD by prevIous stuDIes, WhICH HaVe found large industRiAL FiRms to be mOre capABlE oF ReplacinG oLd, pOlluTED, and eNergY-InEfficienT machiNEs WiTh betteR oNes thaN sMalL anD mid-sIZe fiRms (AndReoni and levinSOn, 2001; Merlevede et aL., 2006; nielsen, 2018). GaininG ThE ADvANtagE of Economies of ScalE Over SmalLEr FirMS, largE firmS aRE aLSo able to consume feweR uNits of EnergY to produce a unIt of output (mACHado et al., 2016; oh anD leE, 2016; park et al., 2016). In addiTion, tHe energy soURces in KiTakyuShu city hAs
 −21.580 −7.144 −13.733 EC T (t−1) −0 .622* **−0. 38 6***  −0. 705*** −0.700* * * Wa ld test 3.755 (0.059)2.419  ( 0 .129 )  0 .222(0.639) 0. 1 6 7 ( 0. 68 5)DW st at. 2 .09  2.36 2 .25 1.91 R 2 0 .9 1 0.87 0.690 .7 1 Adj R2 0 .90  0.83 0.64 0 .63  Bound  t est C (8. 35)  C (6 .40) C (6.15)  C (5.80)  a )  A A A A b) AA AA c)  R A A A d) A A A A* , **, and ***repres en t  s t a tis tic al signifi ca nce a t  10, 5, an d 1 %,r espectively " A" represen t s t he nul lhyp o thesis  is a cc e pte d, while "R " re presentsthe nu l l hypot h esis is  rejec ted  a)  Bre u sc hGod fr e y s e ri alC orr elationLM  t est b ) Br e u s c h-Pa gan /Coo k-Wei sberg test fo r H eter o ske dasti cityc) A RC H tes t d) R amsey  R eset test PALGR AVECOMMUNICA TIO NS  |ht tps:/ / doi.or g/1 0.1 057/s41 599-019 - 036 9- 8 A RT ICLE PALGRAVE COMM UN I C AT IONS | ( 2019)5 :1 56 | https: // doi .org / 1 0.105 7/s4 1 59 9-019-03 69-8 | ww w. nature. co m/palc om ms9 I n thi s  stu dy, th e existi ng in v erted N-shaped relationships of N O2 andCOemissions w itht he i ndus t ri alf irm s ize h in t  a t  the vital contribu ti on oflarge  industrial e nterprises t o  polluti on r e du c tion, as NO2 a nd CO  are prima r ily thewaste  product s of comb u s tion offue l f orpow e r  g eneration and m anuf ac turing.  Th is resu ltcan  be  ex pl ained byprevious  s tu di es , w hichh ave foun dlar ge  in dustr i al fir ms to  bemo re cap able of re p l acin gol d, p oll ut ed, a nd e n erg y-ineff icient ma chi n es w it hbetterones than sma ll  and mid-s iz e f irms ( A n dreoni a nd Levinson, 2001; Merl e vede et  al ., 20 06;Nielsen,201 8). Ga ini n g theadvant age o feco n o mieso f  s cal eover small e r  fi rms,la rgefirms a re also able to co n sum e fewer units  of  ene r g ytop ro d uce  a uni t of output (Mach ado et al. ,2 01 6; Oh andL ee,  2 016; Pa rk et a l., 2 0 16). In  addition , the ene rg y so u r ces  in Kitaky ushu cit y has
 −21.580_−7.144 −13.733_ECT (t−1) −0.622*** −0.386***_−0.705*** −0.700***_Wald_test 3.755_(0.059)_2.419 (0.129) 0.222_(0.639) 0.167 (0.685)_DW stat. 2.09 2.36_2.25 1.91 R2_0.91_0.87 0.69 0.71 Adj R2 0.90 0.83 0.64 0.63 Bound test C (8.35) C_(6.40)_C (6.15)_C_(5.80)_a) A A A A_b) A A A A_c) R_A A A d) A A A A_*,_**, and ***_represent statistical significance at 10, 5, and 1%, respectively_"A" represents the null hypothesis is_accepted, while "R"_represents_the_null hypothesis is rejected_a) Breusch Godfrey serial Correlation LM_test b) Breusch-Pagan/Cook-Weisberg test for Heteroskedasticity_c) ARCH test d) Ramsey Reset test_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 9 In this study,_the existing inverted_N-shaped relationships_of NO2 and_CO emissions with the industrial firm_size hint at_the vital contribution of large industrial_enterprises_to pollution reduction,_as_NO2_and CO_are primarily the_waste_products of_combustion_of fuel for power generation and_manufacturing._This result can be explained by previous_studies, which have found_large_industrial firms to be_more capable of replacing old,_polluted, and energy-inefficient machines with better_ones than_small and_mid-size firms (Andreoni and Levinson, 2001; Merlevede et al., 2006; Nielsen,_2018). Gaining the advantage of economies_of scale over smaller_firms, large_firms_are also able_to_consume fewer_units of energy to produce a unit_of output_(Machado et al., 2016; Oh and_Lee, 2016; Park et_al.,_2016). In addition, the energy sources_in Kitakyushu city has