# Air quality biomonitoring: application of environmental magnetism to provide air pollution cartographies in a road requalification context

Margaux Lefèvre, Patrick Nicol, Thierry Poidras, Davia Dosias-Perla, Pierre Camps

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## To cite this version:

Margaux Lefèvre, Patrick Nicol, Thierry Poidras, Davia Dosias-Perla, Pierre Camps. Air quality biomonitoring: application of environmental magnetism to provide air pollution cartographies in a road requalification context. EGU General Assembly 2023, Apr 2023, Vienna (AUSTRIA), Austria. 2023, 10.5194/egusphere-egu23-12660 . hal-04493931

HAL Id: hal-04493931

https://hal.science/hal-04493931v1

Submitted on 7 Mar 2024

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# Air quality biomonitoring: application of environmental magnetism to provide air pollution cartographies in a road requalification context

Margaux Lefèvre¹, Patrick Nicol¹, Thierry Poidras¹, Davia Dosias-Perla², and Pierre Camps¹

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## I) Particulate matter (PM) : a multi-source origin

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<figure><img src="image_13.png" /><figcaption>**Figure 1 :** Main sources of particulate matter (PM) emissions</figcaption></figure>

<caption>**Figure 2 :** An unmixing problem (adapted from Harisson, 2018)</caption>

Studying the road traffic input on local air quality requires an accurate measurement of the background level. To this end, we defined a relative change from a baseline measurement acquired at reference stations.

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The localization of the reference station as to be carefully chosen.

**How to isolate traffic emissions from other sources ?**

$$RV = \frac{Vstation - Vbase}{Vbase} \rightarrow \text{Car}$$

Adapted from Letaïef et al., 2020

## II) PM capture by plants : an interplay with leaf traits

Typology and composition of plant community

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**Leaf macrostructures**

Surface Thickness

Rigidity Leafstalk length

Margins Phyllotaxis

**Leaf microstructures**

Cuticula Stomata

Trichome Hydathode

Ridges Necrotic spots

Crest

<caption>**Figure 3 :** Plurality of vegetal characteristics having a role in efficiency PM capture</caption>

Plants could be very good pollution sensors, yet their capture efficiency come from a panel of environmental and own morphological characteristics.

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It is Important to work only on a same specie at a time.

## III) Magnetic monitoring of air quality with accumulative surfaces

Target species (not at scale)

<figure><img src="image_18.png" /><figcaption>Pinus halepensis</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>Pinus pinea</figcaption></figure>

<figure><img src="image_20.png" /><figcaption>Arundo donax</figcaption></figure>

Paper filters and humid wipes

Air flow with particulate matters
Cao et al., 2015

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### Mapping dust deposition

Saturation Isothermal Remanent Magnetizations (SRIM) imparted at 1T with an ASC pulse magnetizer were measured with a JR-5A Spinner magnetometer after a relaxation time of 24h.

Leaf surfaces were measured with a leaf scanner (CI-202 Portable Laser, CID Bio-Science). Surface of pine needles were measured with Johnson's (1984) formula involving the total length (l) and the total volume (V) of the needle set :

$$A_{cm^3} = 2l \times \left(1 + \frac{\pi}{n}\right) \times \sqrt{\frac{V_n}{\pi x l}}$$

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We believe important to normalize SIRM by the areas of the accumulative surfaces.

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<figure><img src="image_27.png" /><figcaption>**Figure 4 :** Leaves (A) and needles (B) surfaces acquisitions in our laboratory</figcaption></figure>

## VI) Traceability of PM sources by SEM images

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<figure><img src="image_32.png" /><figcaption>**Figure 5 :** Observed particulate matters (Scanning Electron Microscopy, SEM). A - Cracked cuticle with multiple micro particles (Arundo donax leaf), a potential resuspension source. B - Silica spherule and soot carbon. C - Tire rubber and road wear micro particles aggregated on mycelium matrix. D - Aggregate of metalloid and metal fine dust. E - Copper and iron particle. All identifications have been based on spectral analysis.</figcaption></figure>

## V) Results : a complex and heterogenous air quality

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We believe that is important to keep constant some parameters such as : time exposure, accumulative surface's nature, etc...

<figure><img src="image_35.png" /><figcaption>**Figure 7 :** Dust deposition on Giant reed leaves in a roundabout context (West of Montpellier city, France).</figcaption></figure>

The difference between red and green circles indicates a distance effect between emission's sources and sensors.

The picture A illustrate one of our biosensors station (i.e Giant reed and behind, pine).

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<figure><img src="image_37.png" /><figcaption>**Figure 8 :** A - Effect of environmental openness on PM concentration on pine needles, D123E2 road sector (West of Montpellier city, France). Red to yellow circles illustrate a mixing effect between closed area and traffic conditions (B). Yellow to green circles mostly illustrate a good pollutant atmospheric dispersion due to an open environment (C).</figcaption></figure>

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<figure><img src="image_39.png" /><figcaption>**Figure 9 :** Different pollution patterns (B) obtained from wiping of the guardrails (A), West of Montpellier city, France.</figcaption></figure>

## VI) Conclusions

1 - Working with well chosen reference station

2 - SIRM intensities decrease after a distance of 10 m from the traffic lanes.

3 - Bio and classical magnetic monitoring are relevant tools to make a quick, a low-cost and a suitable air quality diagnostic.