The CACIQUE campaign: understanding the role of

sugarcane agriculture on air pollution in the

Cauca River Valley, ColombiaRodrigo Jimenez 1, Lady Mateus 1, Néstor Y. Rojas 1,

Germán Rueda 2, John H. Reina 3, Germán Restrepo 4, Crystal Weagle 5, Brent N. Holben 6

(1) Universidad Nacional de Colombia – Bogota, Department of Chemical and Environmental Engineering, Air Quality Research Group; rjimenezp@unal.edu.co

(2) Universidad Nacional de Colombia – Palmira(3) Universidad del Valle – Cali; (4) CVC, Cali(5) Dalhousie University, Halifax, NS, Canada

(6) NASA Goddard Space Flight Center, Greenbelt, MD, USA

WorkshopBlack carbon concentrations and emissions in Colombian cities

Cali, November 28-30, 2018

Collaborations and other investigators❑ Universidad Nacional de Colombia –

Palmira: Jennifer Marin, Angela C. Vargas, Svenja Weber

❑ Universidad del Valle: John H. Reina, Carlos A. Melo, Jonnathan Cespedes

❑ Leibniz Institute for Tropospheric Research (TROPOS) – Leipzig, Germany:Alfred Wiedensohler, Dominik van Pinxteren, Hartmut Herrmann

❑ Max Planck Institute forBiogeochemistry – Jena, Germany:Carlos A. Sierra

❑ DAGMA – Cali: Gisella Arizabaleta

Colombia: complex meteorology → AQ❑ Equatorial (moist convection) + very complex topography

(mesoscale thermal circulation) → complex meteorology →mild winds but high turbulence intensity

❑ Several airsheds with different boundary conditions →starting to understand they modulate AQ in Colombia

15-day HYSPLIT back trajectories from UNC sites (receptors at 1 km AGL) during the strong El Niño of January 1992

Bogota

MedellinArauca

Leticia

Palmira

San Andres

V. de Leyva

The Cauca River Valley (CARV)

sugarcane (SC) agro-industry

❑ Added value chain

→ multiple

emission sources

❑ Focus on pre-

harvest burning

economic /

social constraints

❑ High air pollution

toxicity (higher

than from road

traffic)CARV 300 kha

❑ 226 kha sowed

❑ 22 Mton sugarcane/year

❑ 265k employees

❑ 1.5% Colombia’s GDP

❑ 5% Colombia’s

industrial GDP

AQ impact of SC pre-harvest burning

~2.5 g PM2.5 / kg burned DM

~7103 kg DM / ha (leaves)

226 103 ha

fraction of area burned (~20%)

800 ton PM2.5 / year

Significant for

chronic effects

(AQ baseline, public health)

(Unburned HC)

NOx + VOC → O3 / SOA

CACIQUE: CAuca river valley sugarCane pre-

harvest burning aIr QUality Effects

CACIQUE

Scientific questions

▪ What is impact and share of sugarcane pre-harvest

/ prescribed burning on air quality in the Cauca

River Valley (CARV)? (relative contributions to number

and mass of primary and secondary aerosols)

▪ How emitted aerosols physically and chemically

transform along the CARV region? What are the size

distributions of primary and secondary aerosols in

CARV?

▪ Do sugarcane agriculture emissions enhance

photochemical pollution and SOA production?

Sun photometer

max-DOAS

Meteorology

Aerosol sampling

Nephelometer

PM10 beta

Trace gases

U. Nacional – Palmira

IOP 1: 23.7-24.9.2018

IOP 2 pending

Measurement campaign

CVC

mobile

unit

Preliminary results – Cascade impactor

❑ Bimodal

distribution: ~0.9

m, ~5.2 m

❑ Stage-collected

mass will be

chemically

analyzed → size

resolved

composition!

Preliminary results – Nephelometer

AERONET sun photometer

❑ 8 dichroic filters (1020, 940, 870, 675, 500, 440, 380, 340 nm)

❑ Scenarios: Direct, Almucantar, Principal plane

Cimel CE 318N (VBS8, Ver. 5)

Measurements are possible only

under near cloud-free sky conditions

along the optical path

AERONET sun photometer

AERONET sun photometer

AERONET sun photometer

AERONET sun photometer

AERONET sun photometer

AERONET sun photometer

AERONET sun photometer

Conclusions❑ Sugarcane pre-harvest burning emissions in

CARV deserve detailed calculations. First order

calculations suggest PMx emissions are sufficiently

elevated to cause at least chronic atmospheric effects

(baseline augmentation; photochemical pollution,

secondary aerosols?) and derived health effects.

❑ This an ongoing investigation. Regarding PMx, we

expect to report the 1st particle size resolved

chemical characterization in Colombia.

Composition will include EC and OC (and

carbohydrates within).

Conclusions❑ The first results on gravimetric (cascade impactor) and

remote sensing (sun photometer) particle size

distributions show bimodal distributions with a

persistent coarse mode. Fine mode is typically less

important but also persistent.

❑ Ground based sun photometer measurements show a

high temporal variability of both aerosol load,

measured as AOT, and size, measured as

Angstrom exponent. A multiday column dust episode

is clearly seen on the time series.

Thanks for your attention! Questions?Air Quality Research Group

Universidad Nacional de Colombia –Bogota

Sun photometry

𝐼 𝜆 = 𝐼0 𝜆 ∙ 𝑒−𝑎 𝜆 ∙𝑚

𝑚 ≈ 1/ cos 𝑧

m >> 1m = 1

a: Total atmospheric optical thickness (attenuation)

light attenuation (extinction) = scattering (Rayleigh, Mie) + absorption (particle, gas)

I0

m: Air Mass Factor (AMF) radiative transfer

Sun photometry

𝑎 𝜆 = 𝐴𝑂𝑇 𝜆 + 𝑎𝑅 𝜆 +𝑗𝑎𝐺,𝑗 𝜆

𝐴𝑂𝑇 𝜆

𝐴𝑂𝑇 𝜆0=

𝜆

𝜆0

−𝛼

Almucantar Principal plane

(Torres et al, 2013)

Sun photometry – Phase functions Palmira