sus ainabili y
A icle
Ai Quali y and Ac i e T anspo a ion Modes: A Spa io empo al
Concu ence Analysis in Guadalaja a, Mexico
Gab iela Ochoa-Co a ubias 1,* , Ca los González-Figue edo 2, Hugo DeAlba-Ma ínez 2
and Alejand o L. G indlay 3


Ci a ion: Ochoa-Co a ubias, G.;
González-Figue edo, C.;
DeAlba-Ma ínez, H.; G indlay, A.L.
Ai Quali y and Ac i e T anspo a ion
Modes: A Spa io empo al
Concu ence Analysis in Guadalaja a,
Mexico. Sus ainabili y 2021,13, 13904.
h ps://doi.o g/10.3390/su132413904
Academic Edi o s: O iol Ma que
and Monika Wik o ia Maciejewska
Recei ed: 29 Oc obe 2021
Accep ed: 3 Decembe 2021
Published: 16 Decembe 2021
Publishe ’s No e: MDPI s ays neu al
wi h ega d o ju isdic ional claims in
published maps and ins i u ional a il-
ia ions.
Copy igh : © 2021 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
1Depa men o Habi a and U ban De elopmen , ITESO, The Jesui Uni e si y o Guadalaja a,
Tlaquepaque 45604, Mexico
2Depa men o Technological and Indus ial P ocesses, ITESO, The Jesui Uni e si y o Guadalaja a,
Tlaquepaque 45604, Mexico; [email p o ec ed] (C.G.-F.); [email p o ec ed] (H.D.-M.)
3
Depa men o U ban and Regional Planning, Uni e si y o G anada, 18071 G anada, Spain; g indlay@ug .es
*Co espondence: [email p o ec ed]
Abs ac :
The p o ec ion o pedes ians, cyclis s, and public anspo a ion passenge s om en i on-
men al pollu ion is a global conce n. This s udy ills he gap in he exis ing knowledge o empo al
exposu e o ai pollu ion in La in Ame ican me opolises. The pape p oposes a me hodology ad-
d essing he ela ionship be ween wo objec s o s udy, i.e., he use s o ac i e modes o anspo
and ai quali y. This new me hodology assesses he spa io empo al concu ence o bo h objec s
wi h s a is ical analysis o la ge open-access da abases, o p omo e heal hy and sus ainable u ban
mobili y. The applica ion o he empi ical me hodology es ima ed he numbe o use s o ac i e
anspo a ion modes exposed o poo ai quali y episodes in he Guadalaja a me opoli an a ea
(Mexico) in 2019. The s udy conside ed wo pollu an s, ozone (O
3
) and pa icula e ma e (PM
10
),
and wo ac i e modes, cycling and bus apid ansi (BRT). Spa io empo al analyses we e ca ied
ou wi h geog aphic in o ma ion sys ems, as well as wi h nume ic compu ing pla o ms. Fi s , big
da a we e used o coun he numbe o use s o each mode wi hin he a ea o in luence o he ai
quali y moni o ing s a ions. Second, he numbe o ai pollu ion episodes was ob ained using he ai
quali y index p oposed by he En i onmen al P o ec ion Agency (USA) on an hou ly basis. Thi d,
he spa io empo al concu ence be ween ai quali y episodes and ac i e mode use s was calcula ed.
In pa icula , he ai quali y moni o ing da a om he Jalisco A mosphe ic Moni o ing Sys em we e
compa ed o use s o he public bicycle sha e sys em, known as MiBici, and o a bus apid ansi line,
known as Mi Mac o Calzada. The esul s showed ha he numbe o cyclis s and BRT passenge s
exposed o poo ai quali y episodes was conside able in absolu e e ms, ha is, 208,660 use s, while
i was ma ginal when compa ed o he o al numbe o use s exposed o be e ai quali y ca ego ies
in he s udy a ea, who ep esen ed only 10%. To apply he esul s a he me opoli an scale, he spa ial
dis ibu ion o he ai quali y moni o ing sys em should be imp o ed, as well as he a ailabili y o
da a on pedes ians and con en ional bus passenge s.
Keywo ds:
pedes ian; bicycle; ac i e anspo a ion modes; ai quali y; isk; heal h; mass anspo
sys em; bus apid ansi ; GIS; big da a
1. In oduc ion
Ai quali y is a big conce n in ci ies. Since 2016, 90% o wo ldwide ci y dwelle s
li ing in low- and middle-income coun ies ha e b ea hed ai ha did no mee he sa e y
s anda ds se by he Wo ld Heal h O ganiza ion (WHO), causing 4.2 million p ema u e
dea hs due o ai pollu ion [1,2].
Ai pollu ion is he p esence in he ai o ma e (solid pa icles and gases) o o ms o
ene gy ha cause isk, damage, o se ious annoyance o people and o he li ing o ganisms.
Acco ding o he WHO [
2
], PM, ca bon monoxide (CO), ozone (O
3
), ni ogen dioxide (NO
2
),
Sus ainabili y 2021,13, 13904. h ps://doi.o g/10.3390/su132413904 h ps://www.mdpi.com/jou nal/sus ainabili y
Sus ainabili y 2021,13, 13904 2 o 15
and sul u dioxide (SO
2
) a e he pollu an s wi h he s onges e idence o being public
heal h conce ns.
The En i onmen al P o ec ion Agency (EPA) p oposed he uni e sally ecognized ai
quali y index (AQI) [
3
] o assess ai pollu ion. The EPA de ined six ca ego ies acco ding o
pollu an concen a ions. The ca ego ies we e labeled co esponding o he le el o conce n,
ha is, 1, 2, 3, 4, 5, o 6 o good, mode a e, unheal hy o sensi i e g oups, unheal hy, e y
unheal hy, and haza dous conce n, espec i ely.
Speci ically, O
3
and PM pollu ion a g ound le el poses a high isk o heal h [
4
,
5
]
and ha e mul iscale empo al pa e ns. The concen a ions may a y acco ding o he hou
o he day and he season, e.g., O
3
concen a ions a e highe du ing he day ime han a
nigh , and pa icula e ma e , such as PM
10
, is mo e concen a ed in he win e han in he
summe . P ecipi a ions also a ec PM concen a ions [6].
Exposu e o excessi e O
3
can cause b ea hing p oblems, igge as hma, and educe
lung unc ion, leading o lung disease. Addi ionally, b ea hing ai wi h high concen a ions
o PM is conside ed he leading en i onmen al cause o dea h and disease. Bo h long-
e m and sho - e m exposu e o PM a e associa ed wi h mo bidi y and mo ali y om
ca dio ascula and espi a o y diseases [2].
Di e en modes o anspo a e associa ed wi h speci ic e ec s o bad ai condi ions
on heal h [
7
,
8
], o ins ance, he p i a e ca is ecognized as he mos pollu ing mode o
anspo [
9
–
11
]. Recen ly, u ban policies in la ge me opolises ha e p omo ed ac i e ans-
po a ion modes h ough in es men s in in as uc u e, in pa icula , o imp o emen s o
pedes ians, cyclis s, and use s o mass anspo sys ems. Howe e , ac i e modes, such as
walking, cycling, and accessing public anspo s a ions o bus s ops, in ol e a physical
e o [
12
,
13
]. Thus, he ac i i y in ol ed o hese modes equi es mo e inhala ion and,
consequen ly, use s a e mo e sensi i e o ai quali y [
14
,
15
]. The in eg a ion o public and
nonmo o ized anspo ne wo ks in ci ies, as well as he educ ion o he use o p i a e
ca s, will con ibu e o minimizing he heal h isks o pedes ians, cyclis s, and mass public
anspo use s and p omo e sus ainable ci ies [16].
This s udy p oposes a no el me hodology o es ima e he exposu e o use s o ac i e
modes o ai pollu ion. I also seeks o gi e in o ma ion o hese use s on heal hie h eshold
hou s o walking o cycling. This new me hodology in ol es add essing he ela ionship
be ween wo objec s o s udy, i.e., he use s o ac i e modes and ai quali y, assessing he
spa io empo al concu ence o bo h objec s wi h he s a is ical analysis o la ge open access
da abases, o suppo heal hy and sus ainable u ban mobili y. This s udy ca ied ou an
empi ical analysis in he Guadalaja a me opoli an a ea (GMA), Mexico.
This me opolis is one o he mos pollu ed in he coun y and in La in Ame ica [
17
].
Mo eo e , he ci y is suscep ible o pollu ion impac s, since nonmo o ized and public
anspo jou neys p edomina e in he ci y’s modal spli by 40% and 37%, espec i ely.
This sugges s ha a leas wo- hi ds o he popula ion, he ac i e mode use s, may be
ulne able o poo ai quali y condi ions.
This ac shows he impo ance o c oss- empo al and spa ial s udies o iden i y he pol-
lu ion impac s on ci y inhabi an s. This is also ecognized in exis ing
li e a u e [6,7,18–24].
Despi e s udies in Eu ope [
7
,
25
–
27
], he e is a lack o analysis o la ge da abases o empo al
exposu e o ai pollu ion conce ning ac i e mode use s in La in Ame ican me opolises.
A g ea numbe o use s we e expec ed o be exposed due o he his o ical poo ai
quali y episodes in he ci y and he high numbe o ac i e mode use s. Ne e heless,
he esul s showed ha his numbe was smalle han ini ially assumed. E en hough he
ela i e igu es we e low, he absolu e numbe o use s exposed should p omp he adop ion
o public policies o p o ec hem, such as he educ ion o au omobile dependency and he
p omo ion o ac i e anspo a ion modes in he ci y, bene i ing he en i e popula ion.
This a icle is s uc u ed as ollows. The s udy a ea is de ined in Sec ion 2, wi h a ocus
on he ai quali y moni o ing sys em’s a eas o in luence, he bicycle sha e sys em, and he
bus apid ansi (BRT) sys em. The ma e ials and me hods a e p esen ed
in Sec ion 3,
Sus ainabili y 2021,13, 13904 3 o 15
ollowed by he esul s in Sec ion 4. The discussion and conclusions a e included in
Sec ions 4and 5, espec i ely.
2. S udy A ea
The s udy a ea was de ined by he o e lap be ween he ac i e mode s a ions whe e
da a we e a ailable and he a ea o in luence o he ai quali y moni o ing s a ions (AQSs) o
he Jalisco A mosphe ic Moni o ing Sys em (SIMAJ, by i s ini ials in Spanish) in he GMA.
2.1. The Guadalaja a Me opoli an A ea: Geog aphical and Mobili y Con ex
The GMA is he capi al o he Jalisco p o ince. I is an u ban a ea o 5.2 million
inhabi an s in wes e n Mexico [
28
], comp ising nine municipali ies: Guadalaja a, Zapopan,
San Ped o Tlaquepaque, Tonalá, El Sal o, Tlajomulco de Zúñiga, Juanaca lán, Ix lahuacán
de los Memb illos, and Zapo lanejo. As shown in Figu e 1, he ci y is su ounded by moun-
ains o he no hwes , wes , and sou heas . The p e ailing wind ci cula es wes -sou hwes ,
combined wi h a “chimney e ec ” caused by no h-no heas winds [
29
], inc easing he
pollu an concen a ions in he sou h-sou heas sec o o he ci y.
Sus ainabili y 2021, 13, x FOR PEER REVIEW 3 o 15
A g ea numbe o use s we e expec ed o be exposed due o he his o ical poo ai
quali y episodes in he ci y and he high numbe o ac i e mode use s. Ne e heless, he
esul s showed ha his numbe was smalle han ini ially assumed. E en hough he el-
a i e igu es we e low, he absolu e numbe o use s exposed should p omp he adop ion
o public policies o p o ec hem, such as he educ ion o au omobile dependency and
he p omo ion o ac i e anspo a ion modes in he ci y, bene i ing he en i e popula ion.
This a icle is s uc u ed as ollows. The s udy a ea is de ined in Sec ion 2, wi h a
ocus on he ai quali y moni o ing sys em’s a eas o in luence, he bicycle sha e sys em,
and he bus apid ansi (BRT) sys em. The ma e ials and me hods a e p esen ed in Sec-
ion 3, ollowed by he esul s in Sec ion 4. The discussion and conclusions a e included
in Sec ions 4 and 5, espec i ely.
2. S udy A ea
The s udy a ea was de ined by he o e lap be ween he ac i e mode s a ions whe e
da a we e a ailable and he a ea o in luence o he ai quali y moni o ing s a ions (AQSs)
o he Jalisco A mosphe ic Moni o ing Sys em (SIMAJ, by i s ini ials in Spanish) in he
GMA.
2.1. The Guadalaja a Me opoli an A ea: Geog aphical and Mobili y Con ex
The GMA is he capi al o he Jalisco p o ince. I is an u ban a ea o 5.2 million in-
habi an s in wes e n Mexico [28], comp ising nine municipali ies: Guadalaja a, Zapopan,
San Ped o Tlaquepaque, Tonalá, El Sal o, Tlajomulco de Zúñiga, Juanaca lán, Ix lahuacán
de los Memb illos, and Zapo lanejo. As shown in Figu e 1, he ci y is su ounded by
moun ains o he no hwes , wes , and sou heas . The p e ailing wind ci cula es wes -
sou hwes , combined wi h a “chimney e ec ” caused by no h-no heas winds [29], in-
c easing he pollu an concen a ions in he sou h-sou heas sec o o he ci y.
Figu e 1. Ai quali y moni o ing s a ions and ac i e modes s a ions in he Guadalaja a me opoli an
a ea, Mexico. The Figu e shows ai quali y moni o ing s a ions (AQSs) o he Jalisco A mosphe ic
Figu e 1.
Ai quali y moni o ing s a ions and ac i e modes s a ions in he Guadalaja a me opoli an
a ea, Mexico. The Figu e shows ai quali y moni o ing s a ions (AQSs) o he Jalisco A mosphe ic
Moni o ing Sys em (SIMAJ, om i s ini ials in Spanish) and hei a ea o in luence (AI), he s a ions
o he bicycle sha e sys em (MiBici), con en ional bus s ops, and s a ions o he U ban Elec ic T ain
Sys em (SITEUR, om i s ini ials in Spanish), i.e., ligh ail ansi (LRT), bus apid ansi (BRT),
and high-quali y buses (HQB). Sou ce: au ho s based on [30–35].
The me opoli an a ea has a semiwa m clima e, wi h some hea island episodes. The e
a e empe a u e in e sions in he ci y on 78% o he days o he yea , mainly be ween
No embe and June. This phenomenon a o s he o ma ion o O
3
and makes i di icul o
ola ile compounds such as PM
10
o dispe se. Howe e , he si ua ion imp o es in he ainy
Sus ainabili y 2021,13, 13904 4 o 15
season (June–Augus ) as he pollu an s, mainly he PM
10
, suspended in he a mosphe e
p ecipi a e [29].
Ai quali y is a g owing conce n in he GMA. Quan i ying and moni o ing ai pollu ion
is he i s s ep o educe exposu e o ai pollu ion [
2
]. The local go e nmen moni o s
he ai quali y h ough he SIMAJ [
36
] and o e s eal- ime ai pollu ion measu emen s.
Figu e 1shows he en ixed AQSs. The AQSs measu e he concen a ion o i e pollu an s
(CO, PM
10
, O
3
, SO
2
, NO
2
) as well as me eo ological a iables (ambien empe a u e,
ela i e humidi y, and wind speed and di ec ion). The da a a e used as he inpu o he
announcemen o en i onmen al ale s in he ci y.
Figu e 1shows he he e ogenous spa ial pa e n o he AQSs ha pa ially assess
he ambien pollu ion in he me opolis. Juanaca lán, Ix lahuacán de los Memb illos,
Tlajomulco de Zúñiga, and Zapo lanejo a e mos ly ou side he SIMAJ’s a ea o in luence,
while El Sal o, Tonalá, Tlaquepaque, and Zapopan a e only pa ly inside his a ea. Only
he Guadalaja a municipali y has accep able co e age by he SIMAJ.
Acco ding o he Na ional Ins i u e o Ecology and Clima e Change (Mexico) [
10
],
in 2019, he numbe o days on which he maximum ecommended h esholds we e
exceeded, in a leas one pa ame e , o any pollu an in he GMA was 267 days. This is
6% mo e han he numbe egis e ed in 2018 and ep esen s wo hi ds o he yea wi h
excessi e le els o ai pollu ion. The igu es in Table 1 e eal ha PM
10
and O
3
a e he
pollu an s ha mos equen ly exceed he s anda ds. Gi en hese igu es, his s udy
ocused on PM10 and O3as he pollu an s o be analyzed.
Table 1. Ambien pollu an s in he Guadalaja a me opoli an a ea in 2019. Sou ce: au ho s, based on [10].
Pollu an Assessmen Uni Value S anda d [NOM-Mexico] Numbe o Days abo e S anda d
O38 h ppm 0.146 0.070 39.50%
PM10 24 h µg/m3261 75 41.10%
CO 8 h ppm 3.6 11 N/A
NO21 h ppm 0.203 0.210 N/A
SO28 h ppm 0.013 0.2 N/A
N/A: Nonapplicable; ppm = pa s pe million.
P i a e ehicles a e ecognized as he main sou ce o ambien ai pollu ion in ci ies [
37
],
and he GMA is no excep ion [
38
,
39
]. Be ween 1980 and 2010, he low-densi y u ban
de elopmen pa adigm in he ci y inc eased indi idual mo o ized ips by mo e han
942% [17].
Mass anspo sys ems a e ecognized as a solu ion o sus ainable anspo de-
elopmen [
26
] and a ca alys o be e ai quali y, despi e he nega i e impac s du ing
hei cons uc ion [
27
]. Ne e heless, hei con ibu ion o he GMA modal sha e is e y
limi ed. Acco ding o he Jalisco S a e Go e nmen [
17
], 37% o he ips in he GMA a e
made on oo , 3% by bicycle, 37% by public anspo a ion, and 23% by p i a e ehicles.
The mass anspo sys ems ba ely con ibu e, wi h only 3% o he modal sha e. I is
ecognized ha commu ing on oo and by bicycle can signi ican ly educe u ban pollu an
emissions [
40
,
41
]. Acco ding o he Na ional Ins i u e o S a is ics and Geog aphy (INEGI,
om i s ini ials in Spanish) [
28
], 25% o dwellings in he GMA ha e a bicycle as a po en ial
means o anspo a ion. This igu e con as s wi h he con ibu ion o cycling o he modal
spli in he ci y [42].
His o ically, ca s ha e been a o ed in he GMA wi h la ge in as uc u e in es men s.
Recen ly, he go e nmen , mo i a ed by communi y associa ions and academic ins i u ions,
has p omo ed a sus ainable mobili y pa adigm, pa icula ly h ough ac i e modes, e.g.,
imp o emen s o he ne wo k o bike lanes, he expansion o he bicycle sha e sys em
(known as MiBici), as well as he enhancemen o he U ban Elec ic T ain Sys em (SITEUR,
om i s ini ials in Spanish).
MiBici is he public bicycle sha e sys em in he ci y, es ablished in 2014 and ecognized
as one o he bes bicycle sha e sys ems in he coun y in 2019 [
43
]. The sys em se es
mo e han 86,000 cyclis s h ough 3200 bicycles and 300 s a ions [
44
]. Balde as e al. [
16
]
Sus ainabili y 2021,13, 13904 5 o 15
s a e ha one o he main easons use s choose MiBici is he low cos compa ed wi h o he
anspo a ion modes. The Cicloci ies Ranking 2019 [
43
] s a es ha he local go e nmen s
o Guadalaja a, Zapopan, and Tlaquepaque ha e enhanced he cycling in as uc u e by
deploying public specialis s in mobili y and by gi ing i p io i y in planning bodies.
Figu e 1shows ha he spa ial dis ibu ion o MiBici is loca ed mainly in Guadalaja a,
o a ce ain ex en in Zapopan, and e y li le in Tlaquepaque. This ne wo k is nonexis en
in he es o he GMA municipali ies. Cycling ep esen s a ound 2% o he o al modal spli
in he GMA [
42
]. The peak hou s o use o he MiBici sys em a e 8:00 a.m.
and 6:00 p.m.
Acco ding o Jalisco Cómo Vamos [
45
], MiBici egis e ed an a e age o mo e han 2.8 million
annual cycling ips in he pe iod 2014–2020. The same sou ce epo s ha he kilome e s
o bicycle lanes inc eased i e- old be ween 2015 and 2020, o aling 182 km. The highes
numbe o ips since he ope a ion began was in 2019, wi h 4,660,470 ips aken by mo e
han 27 housand use s, wi h an a e age a el ime o 12:32 min [44]. The he e ogeneous
spa ial dis ibu ion o MiBici shows a wes –eas pa e n limi ed o he co e o he ci y
(Figu e 1).
The SITEUR has ope a ed since 1989. The public ca ie se es mo e han 98.5 million
passenge s a yea h ough 121 s a ions, i.e., 3.23% o he o al modal spli in he ci y, mainly
wi h ligh ail ain and BRT [
17
]. This s udy coun ed he BRT Line 1 passenge s, due o
he da a a ailabili y when his esea ch was conduc ed. The BRT Line 1, known as Mi
Mac o Calzada, is 16.6 km long wi h 27 s a ions, and has been in ope a ion since 2009.
I accoun s o 30.3% o SITEUR ips. The main line plus he 15 eeding lines se ed
44.2 million passenge s in 2020, [
46
] wi h a i e-minu e equency (mo ning peak hou ) [
47
].
As shown in Figu e 1, he BRT is no h–sou h o ien ed and only se es he Guadalaja a
municipali y up o he Tlaquepaque bounda y.
2.2. The Jalisco A mosphe ic Moni o ing Sys em’s A ea o In luence
The s udy a ea was de e mined by he SIMAJ’s co e age and he da a a ailabili y
on an hou ly basis. The spa ial dis ibu ion o he AQSs does no co e he GMA’s en i e
u ban oo p in , as shown in Figu e 1. Mo eo e , acco ding o he SIMAJ [
48
], he AQSs
ha e a wo-kilome e a ea o in luence, o which eal- ime hou ly measu emen s o PM
10
concen a ions in mic og ams pe cubic me e and O
3
in pa s pe million a e eco ded;
hese concen a ions a e used o calcula e hei ela ed AQIs.
The spa ial concu ence be ween he AQSs’ a eas o in luence and he ac i e modes o
anspo s ops/s a ions was iden i ied h ough a geog aphic in o ma ion sys em (A cGis
P o, ESRI
®
, Redlands, CA, USA). The calcula ions included 10 AQSs, 287 bike sha e s a ions,
9073 con en ional bus s ops, 77 BRT s a ions, and 48 ligh ail ansi s a ions [30,35].
Ai quali y moni o ing da a a ec ing mos o he ac i e mode use s we e no a ailable.
Figu e 2highligh s he na ow co e age o he AQSs wi h espec o he ac i e mode
s ops/s a ions. Thi y-se en pe cen o he MiBici s a ions, 28% o he con en ional bus
s ops, 44% o he BRT s a ions, 22% o he high-quali y bus s ops, and 38% o he ligh
ail ain s a ions we e ou side he a ea o in luence o he AQSs in he ci y. Only 107 o
he MiBici s a ions we e included in he a ea o in luence o ou AQSs: A emajac, Cen o,
Tlaquepaque, and Valla a. Simila ly, only wel e BRT s a ions we e conside ed o his
s udy, as hey ell inside o he AQSs’ a eas o in luence. Speci ically, he BRT s a ions
loca ed wi hin he a ea o in luence o he Cen o AQS we e Ciencias de la Salud (10),
Juan Ál a ez (11), Alameda (12), San Juan de Dios (13), Bicen ena io (14), La Paz (15),
and Niños Hé oes (16). The s a ions in he a ea o in luence o he Mi a alle AQS
we e López de Legazpi (23), Clemen e O ozco (24), A es Plás icas (25), Escul u as (26),
and F ay Angélico (27).

Sus ainabili y 2021,13, 13904 6 o 15
Sus ainabili y 2021, 13, x FOR PEER REVIEW 6 o 15
s udy, as hey ell inside o he AQSs’ a eas o in luence. Speci ically, he BRT s a ions
loca ed wi hin he a ea o in luence o he Cen o AQS we e Ciencias de la Salud (10), Juan
Á l a ez (11), Alameda (12), San Juan de Dios (13), Bicen ena io (14), La Paz (15), and Ni-
ños Hé oes (16). The s a ions in he a ea o in luence o he Mi a alle AQS we e López de
Legazpi (23), Clemen e O ozco (24), A es Plás icas (25), Escul u as (26), and F ay An-
gélico (27).
Un o una ely, no da a o he con en ional and high-quali y buses o he ligh ail
ains we e a ailable on an hou ly basis. Thus, due o he SIMAJ’s spa ial pa e n, oge he
wi h he da a a ailabili y, i e AQSs, 107 MiBici s a ions, and 12 BRT s a ions we e con-
side ed o he compu a ions.
Figu e 2. S udy a ea. The igu e shows he a ea o in luence (AI) o he ai quali y moni o ing s a ions (AQSs) managed
by he Jalisco A mosphe ic Moni o ing Sys em (SIMAJ, om i s ini ials in Spanish). The map highligh s he ac i e mode
s a ions conside ed in he s udy, i.e., 107 s a ions o he MiBici bicycle sha e sys em and 12 bus apid ansi (BRT) s a ions.
Sou ce: au ho s based on [30–34].
3. Da a Sou ces and Me hods
The WHO s a es ha using la ge yea ly da abases allows ou comes o be e ined,
aking in o accoun seasonal a ia ions [8]. The analysis assessed da a om he selec ed
s a ions in 2019. This yea was chosen as he e e ence yea o p e en mis ep esen a ion
due o changes in a el beha io s caused by he COVID-19 pandemic in 2020 and 2021.
An hou ly ime scale was selec ed due o he O3 and PM10 empo al beha io , and da a
Figu e 2.
S udy a ea. The igu e shows he a ea o in luence (AI) o he ai quali y moni o ing s a ions (AQSs) managed
by he Jalisco A mosphe ic Moni o ing Sys em (SIMAJ, om i s ini ials in Spanish). The map highligh s he ac i e mode
s a ions conside ed in he s udy, i.e., 107 s a ions o he MiBici bicycle sha e sys em and 12 bus apid ansi (BRT) s a ions.
Sou ce: au ho s based on [30–34].
Un o una ely, no da a o he con en ional and high-quali y buses o he ligh ail
ains we e a ailable on an hou ly basis. Thus, due o he SIMAJ’s spa ial pa e n, o-
ge he wi h he da a a ailabili y, i e AQSs, 107 MiBici s a ions, and 12 BRT s a ions we e
conside ed o he compu a ions.
3. Da a Sou ces and Me hods
The WHO s a es ha using la ge yea ly da abases allows ou comes o be e ined,
aking in o accoun seasonal a ia ions [
8
]. The analysis assessed da a om he selec ed
s a ions in 2019. This yea was chosen as he e e ence yea o p e en mis ep esen a ion
due o changes in a el beha io s caused by he COVID-19 pandemic in 2020 and 2021.
An hou ly ime scale was selec ed due o he O
3
and PM
10
empo al beha io , and da a
a ailabili y. This s udy bene i ed om open da a a ailabili y o all AQSs [
48
], pa icula ly
o O3and PM10.
Nonmo o ized modes and public anspo accoun o 77% o ips in he ci y [
17
].
Disappoin ingly, no da a on pedes ian ips we e a ailable, no ips made by p i a ely
owned bicycles. The MiBici open da a sys em [
49
] was accessed o ob ain he o al ip
egis e s o o om any o i s ancho ing s a ions o 2019. The SITEUR epo ed he numbe
Sus ainabili y 2021,13, 13904 7 o 15
o passenge s en e ing he BRT s a ions hou ly [
50
]. No da a o ligh ail ains we e
a ailable a he equi ed accu acy.
As a consequence o da a a ailabili y, he eina e , he e m “ac i e mode use s” e e s
o ips ia MiBici and pedes ians accessing BRT s a ions in he a eas o in luence o AQSs.
Table 2shows da a sou ces and eco ding equency o each kind o s a ion compu ed in
his s udy, i.e., AQS, MiBici, and BRT.
Table 2.
Sou ces o da a on ai quali y moni o ing and ac i e anspo a ion modes in he Guadalaja a me opoli an a ea
in 2019.
S a ion Da a Tempo al Basis * Numbe
o Reco ds Sou ce
Ai quali y O3and PM10 concen a ion Hou 87,600 Minis y o he En i onmen and Te i o ial
De elopmen (Semade , Jalisco, Mexico) SIMAJ [
36
,
48
]
Ac i e anspo a ion
mode
Bicycle in–ou ancho s Minu e 2,388,884
Go e nmen o he S a e o Jalisco, Mexico: MiBici [
49
]
Passenge s coming in o he
BRT s a ion Hou 105,120 U ban Elec ic T ain Sys em, Guadalaja a [50]
* Fo he yea 2019.
A s a is ical spa io empo al app oach was used. The yea 2019 was chosen as he
mos ecen yea wi hou po en ial changes o a el beha io s due o he COVID-19
pandemic [7]. Figu e 3shows he concep ual model used o iden i y he numbe o ac i e
mode use s exposed o poo ai quali y episodes in he e e ence yea . Fi s , he ac i e
mode da abase was o ganized o iden i y he numbe o ac i e mode use s in he AQSs’
a eas o in luence, on an hou ly basis. Then, he numbe o episodes pe hou in each
AQS a ea was assessed using he ai quali y index [
3
]. Finally, he concu ence be ween
pollu an s and use s o ac i e anspo a ion modes was assessed.
Sus ainabili y 2021, 13, x FOR PEER REVIEW 8 o 16
Figu e 3. Concep ual model. Ac i e modes analyzed we e bicycle sha e sys em and bus apid ansi
(BRT). Pollu an s compu ed we e ozone (O3) and pa icula e ma e (PM10). Ai quali y index (AQI)
e e s o he En i onmen al P o ec ion Agency index [3]. The wo d “use s” e e s o bo h bicycle
ips and BRT passenge s.
3.1. Ac i e Mode Da a Managemen
Da a om he 107 MiBici s a ions we e used o calcula e he numbe o ips pe hou
linked o each AQS. The da a we e managed using Py hon p og amming language and
Pandas, among o he lib a ies. The ollowing assump ions we e made o compu e bicycle
ips and c ea e a da abase ha would be compa ible wi h AQS da a. Fi s , one hou was
added o he empo al da a. Second, bicycle ips a eling a leas one minu e inside he
AQS’s a ea o in luence we e quan i ied as one ip in he co esponding hou . Thi d, he
cyclis s we e exposed o ai quali y episodes bo h when s a ing and ending he ip a he
s a ion, and hus coun ed wice. Howe e , i a cyclis s a ed and inished he ip a s a-
ions linked o he same AQS, i was coun ed as only one ip.
The SITEUR also p o ided hou ly da a on people accessing he 12 selec ed BRT s a-
ions. The e we e no da a o passenge s lea ing he s a ions; hese esul s we e unde es-
ima ed, since BRT use s we e only coun ed as passenge s accessing he BRT and no as
pedes ians a e hei ansi jou ney.
3.2. Alloca ion o Episodes by AQI Ca ego y
AQI was assessed o alloca e a ca ego y o O3 and PM10 pollu ion in he i e AQSs
s udied. The AQI was designed by he EPA [51], and calcula ions we e pe o med using
he MATLAB p og amming language.
Fi s , mo ing a e ages o pollu an concen a ions we e calcula ed o 8 and 24 h ime
windows, o O3 and PM10, espec i ely. The AQI was calcula ed by subs i u ing he mo -
ing a e ages di ec ly in Equa ion (1). Nex , he AQI was classi ied acco ding o he es ab-
lished ca ego ies desc ibed in he in oduc ion (Sec ion 1). Finally, he numbe o episodes
in AQI ca ego ies 3, 4, and 5 we e linked o AQSs o each hou o he yea ; hese h ee
ca ego ies co espond o poo ai quali y episodes.
Figu e 3.
Concep ual model. Ac i e modes analyzed we e bicycle sha e sys em and bus apid ansi (BRT). Pollu an s
compu ed we e ozone (O
3
) and pa icula e ma e (PM
10
). Ai quali y index (AQI) e e s o he En i onmen al P o ec ion
Agency index [3]. The wo d “use s” e e s o bo h bicycle ips and BRT passenge s.
Sus ainabili y 2021,13, 13904 8 o 15
3.1. Ac i e Mode Da a Managemen
Da a om he 107 MiBici s a ions we e used o calcula e he numbe o ips pe hou
linked o each AQS. The da a we e managed using Py hon p og amming language and
Pandas, among o he lib a ies. The ollowing assump ions we e made o compu e bicycle
ips and c ea e a da abase ha would be compa ible wi h AQS da a. Fi s , one hou was
added o he empo al da a. Second, bicycle ips a eling a leas one minu e inside
he AQS’s a ea o in luence we e quan i ied as one ip in he co esponding hou . Thi d,
he cyclis s we e exposed o ai quali y episodes bo h when s a ing and ending he ip a
he s a ion, and hus coun ed wice. Howe e , i a cyclis s a ed and inished he ip a
s a ions linked o he same AQS, i was coun ed as only one ip.
The SITEUR also p o ided hou ly da a on people accessing he 12 selec ed BRT
s a ions. The e we e no da a o passenge s lea ing he s a ions; hese esul s we e unde -
es ima ed, since BRT use s we e only coun ed as passenge s accessing he BRT and no as
pedes ians a e hei ansi jou ney.
3.2. Alloca ion o Episodes by AQI Ca ego y
AQI was assessed o alloca e a ca ego y o O
3
and PM
10
pollu ion in he i e AQSs
s udied. The AQI was designed by he EPA [
51
], and calcula ions we e pe o med using
he MATLAB p og amming language.
Fi s , mo ing a e ages o pollu an concen a ions we e calcula ed o 8 and 24 h
ime windows, o O
3
and PM
10,
espec i ely. The AQI was calcula ed by subs i u ing he
mo ing a e ages di ec ly in Equa ion (1). Nex , he AQI was classi ied acco ding o he
es ablished ca ego ies desc ibed in he in oduc ion (Sec ion 1). Finally, he numbe o
episodes in AQI ca ego ies 3, 4, and 5 we e linked o AQSs o each hou o he yea ; hese
h ee ca ego ies co espond o poo ai quali y episodes.
AQI = [(AQIHi −AQILo)/(ConcHi −ConcLo)] ×(Conci−concLo) + (AQILo) (1)
whe e
Conci= Inpu concen a ions o a gi en pollu an ;
ConcLo = The concen a ion b eakpoin ha is less han o equal o Conci;
ConcHi = The concen a ion b eakpoin ha is g ea e han o equal o Conci;
AQILo = The AQI alue/b eakpoin co esponding o ConcLo;
AQIHi = The AQI alue/b eakpoin co esponding o ConcHi.
3.3. Concu ence Analysis
The concu ence analysis implied s a i ied compu a ions o wo inpu s: i s , o he
numbe o MiBici ips and BRT passenge s pe hou in he i e AQSs’ a eas o in luence;
hen, o he numbe o poo ai quali y episodes alling in o ca ego ies 3, 4, o 5. I was
assumed ha he en i e s udy a ea had he same compensa ion o calcula e exposu e o
pollu an s. The concu ence analysis was compu ed wi h dynamic ables on a sp eadshee
(Excel, MSO ice
®
, Redmond, WA, USA), associa ing spa io empo al co espondence. As
a esul , he numbe o ac i e mode use s exposed o ca ego y 3, 4, o 5 episodes was
es ima ed, bo h o O3and PM10.
4. Resul s
4.1. Ac i e Mode Da a Managemen
As expec ed, he numbe o passenge s who walked o access he 12 mass anspo
BRT s a ions was highe han he numbe o ips logged a he 104 MiBici s a ions, ha
is, 20,028,250 and 2,388,884, espec i ely. Figu e 4displays he numbe o annual ac i e
mode use s s udied on an hou ly basis. Figu e 4a shows ha mos o he MiBici ips we e
in he a ea o in luence o he Cen o AQS. All s a ions egis e ed wo peak hou s, i.e., 9:00
and 19:00. A 9:00, he e we e 131,608, 17,005, and 41,602 ips in he a ea o in luence o
AQS Cen o, Tlaquepaque, and Valla a, espec i ely. These igu es inc eased a 19:00 in
Sus ainabili y 2021,13, 13904 9 o 15
he same a eas o in luence, ha is, 153,314, 21,062, and 58,179 ips, espec i ely This was
concu en wi h he s anda d wo king hou s in he ci y. In addi ion, he ips linked o he
Cen o s a ion also showed a peak hou a 14:00 (lunch ime), i.e., 129,274 ips.
Sus ainabili y 2021, 13, x FOR PEER REVIEW 9 o 15
he same a eas o in luence, ha is, 153,314, 21,062, and 58,179 ips, espec i ely This was
concu en wi h he s anda d wo king hou s in he ci y. In addi ion, he ips linked o he
Cen o s a ion also showed a peak hou a 14:00 (lunch ime), i.e., 129,274 ips.
The spa ial pa e n o he BRT passenge s was simila , al hough he s a ions ha con-
ibu ed o he peak hou s we e clea ly dis inguished. Figu e 4b shows he h ee peak
hou s a he BRT s a ions in he a ea o in luence o he Cen o and Mi a alle AQSs, ha
is, be ween 8:00 and 9:00, be ween 14:00 and 15:00, and be ween 19:00 and 20:00. O he 20
million passenge s using hese s a ions, 60% we e in he a ea o in luence o he Cen o
AQS and 40% in ha o he Mi a alle s a ion, i.e., 12,208,712 and 7,819,538, espec i ely.
Mo eo e , i was shown ha 1,832,788 passenge s walked o each BRT s a ions in he
icini y o he Mi a alle AQS be ween 8:00 and 9:00, and 2,152,791 passenge s accessed
BRT s a ions a ound he Cen o AQS be ween 19:00 and 20:00. This can be explained by
he ac ha he o me AQS se es a mos ly esiden ial a ea, while he la e se es a eas
wi h a high densi y o wo kplaces, pa icula ly e ail ade and public se ices.
(a)
(b)
(c)
(d)
Figu e 4. Ac i e mode use s and poo ozone (O3) o pa icula e ma e (PM10) episodes in he s udy a ea on an hou ly basis.
The o de o magni ude be ween igu es mus be conside ed o p ope ly compa e hem. (a,b) e e o he annual numbe
o MiBici ips and bus apid ansi (BRT) passenge s, espec i ely. (c,d) show he numbe o days wi h episodes wi hin
he wo s ai quali y index (AQI) ca ego ies o O3 and PM10, espec i ely.
4.2. Alloca ion o Episodes by AQI Ca ego y
The AQI calcula ions emphasized ca ego ies h ee, ou , and i e. Acco ding o he
EPA, ca ego ies ou and i e s ongly a ec ed use s in ac i e modes. No consensus was
ound ega ding he impac o ca ego y h ee episodes on ac i e mode use s. E en hough
he En i onmen al P o ec ion Agency does no explici ly include cyclis s as a sensi i e
g oup, some o ganiza ions p omo e he use o ace masks o cyclis s iding wi hin a eas
in AQI ca ego y h ee. Thus, his ca ego y was compu ed o accoun o cyclis s’ exposu e
o pollu an s.
Figu e 4.
Ac i e mode use s and poo ozone (O
3
) o pa icula e ma e (PM
10
) episodes in he s udy a ea on an hou ly basis.
The o de o magni ude be ween igu es mus be conside ed o p ope ly compa e hem. (
a
,
b
) e e o he annual numbe o
MiBici ips and bus apid ansi (BRT) passenge s, espec i ely. (
c
,
d
) show he numbe o days wi h episodes wi hin he
wo s ai quali y index (AQI) ca ego ies o O3and PM10, espec i ely.
The spa ial pa e n o he BRT passenge s was simila , al hough he s a ions ha
con ibu ed o he peak hou s we e clea ly dis inguished. Figu e 4b shows he h ee peak
hou s a he BRT s a ions in he a ea o in luence o he Cen o and Mi a alle AQSs, ha is,
be ween 8:00 and 9:00, be ween 14:00 and 15:00, and be ween 19:00 and 20:00. O he
20 million passenge s using hese s a ions, 60% we e in he a ea o in luence o he Cen o
AQS and 40% in ha o he Mi a alle s a ion, i.e., 12,208,712 and 7,819,538, espec i ely.
Mo eo e , i was shown ha 1,832,788 passenge s walked o each BRT s a ions in he
icini y o he Mi a alle AQS be ween 8:00 and 9:00, and 2,152,791 passenge s accessed
BRT s a ions a ound he Cen o AQS be ween 19:00 and 20:00. This can be explained by
he ac ha he o me AQS se es a mos ly esiden ial a ea, while he la e se es a eas
wi h a high densi y o wo kplaces, pa icula ly e ail ade and public se ices.
4.2. Alloca ion o Episodes by AQI Ca ego y
The AQI calcula ions emphasized ca ego ies h ee, ou , and i e. Acco ding o he
EPA, ca ego ies ou and i e s ongly a ec ed use s in ac i e modes. No consensus was
ound ega ding he impac o ca ego y h ee episodes on ac i e mode use s. E en hough
he En i onmen al P o ec ion Agency does no explici ly include cyclis s as a sensi i e
g oup, some o ganiza ions p omo e he use o ace masks o cyclis s iding wi hin a eas in
AQI ca ego y h ee. Thus, his ca ego y was compu ed o accoun o cyclis s’ exposu e
o pollu an s.