@article{fdi:010074355,
  title = {{B}lack carbon emission and transport mechanisms to the free troposphere at the {L}a {P}az/{E}l {A}lto ({B}olivia) metropolitan area based on the {D}ay of {C}ensus (2012)},
  author = {{W}iedensohler, {A}. and {A}ndrade, {M}. and {W}einhold, {K}. and {M}uller, {T}. and {B}irmili, {W}. and {V}elarde, {F}. and {M}oreno, {I}. and {F}orno, {R}. and {S}anchez, {M}. {F}. and {L}aj, {P}. and {G}inot, {P}atrick and {W}hiteman, {D}. {N}. and {K}rejci, {R}. and {S}ellegri, {K}. and {R}eichler, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{U}rban development, growing industrialization, and increasing demand for mobility have led to elevated levels of air pollution in many large cities in {L}atin {A}merica, where air quality standards and {WHO} guidelines are frequently exceeded. {T}he conurbation of the metropolitan area of {L}a {P}az/{E}l {A}lto is one of the fastest growing urban settlements in {S}outh {A}merica with the particularity of being located in a very complex terrain at a high altitude. {A}s many large cities or metropolitan areas, the metropolitan area of {L}a {P}az/{E}l {A}lto and the {A}ltiplano region are facing air quality deterioration. {L}ong-term measurement data of the equivalent black carbon (e{BC}) mass concentrations and particle number size distributions ({PNSD}) from the {G}lobal {A}tmosphere {W}atch {O}bservatory {C}hacaltaya ({CHC}; 5240 m a.s.l., above sea level) indicated a systematic transport of particle matter from the metropolitan area of {L}a {P}az/{E}l {A}lto to this high altitude station and subsequently to the lower free troposphere. {T}o better understand the sources and the transport mechanisms, we conducted e{BC} and {PNSD}s measurements during an intensive campaign at two locations in the urban area of {L}a {P}az/{E}l {A}lto from {S}eptember to {N}ovember 2012. {W}hile the airport of {E}l {A}lto site (4040 m a.s.l.) can be seen as representative of the urban and {A}ltiplano background, the road site located in {C}entral {L}a {P}az (3590 m a.s.l.) is representative for heavy traffic-dominated conditions. {P}eaks of e{BC} mass concentrations up to 5 mu g m(-3) were observed at the {E}l {A}lto background site in the early morning and evening, while minimum values were detected in the early afternoon, mainly due to thermal convection and change of the planetary boundary layer height. {T}he traffic-related e{BC} mass concentrations at the road site reached maximum values of 10-20 mu g m(-3). {A} complete traffic ban on the specific {B}olivian {D}ay of {C}ensus ({N}ovember 21, 2012) led to a decrease of e{BC} below 1 mu g m(-3) at the road site for the entire day. {C}ompared to the day before and after, particle number concentrations decreased by a factor between 5 and 25 over the particle size range from 10 to 800 nm, while the submicrometer particle mass concentration dropped by approximately 80%. {T}hese results indicate that traffic is the dominating source of {BC} and particulate air pollution in the metropolitan area of {L}a {P}az/{E}l {A}lto. {I}n general, the diurnal cycle of e{BC} mass concentration at the {C}hacaltaya observatory is anti-correlated to the observations at the {E}l {A}lto background site. {T}his pattern indicates that the traffic-related particulate matter, including {BC}, is transported to higher altitudes with the developing of the boundary layer during daytime. {T}he metropolitan area of {L}a {P}az/{E}l {A}lto seems to be a significant source for {BC} of the regional lower free troposphere. {F}rom there, {BC} can be transported over long distances and exert impact on climate and composition of remote southern hemisphere.},
  keywords = {{B}lack carbon ; {T}raffic emissions ; {P}ollution transport ; {F}ree troposphere ; {BOLIVIE} ; {LA} {PAZ} ; {EL} {ALTO}},
  booktitle = {},
  journal = {{A}tmospheric {E}nvironment},
  volume = {194},
  numero = {},
  pages = {158--169},
  ISSN = {1352-2310},
  year = {2018},
  DOI = {10.1016/j.atmosenv.2018.09.032},
  URL = {https://www.documentation.ird.fr/hor/fdi:010074355},
}