Mass concentration measurements of autumn bioaerosol using low-cost sensors in a mature temperate woodland free-air carbon dioxide enrichment (FACE) experiment: investigating the role of meteorology and carbon dioxide levels
<p>Forest environments contain a wide variety of airborne biological particles (bioaerosols), including pollen, fungal spores, bacteria, viruses, plant detritus, and soil particles. Forest bioaerosol plays a number of important roles related to plant and livestock health, human disease and all...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-05-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/19/2653/2022/bg-19-2653-2022.pdf |
| Summary: | <p>Forest environments contain a wide variety of airborne biological particles
(bioaerosols), including pollen, fungal spores, bacteria, viruses, plant
detritus, and soil particles. Forest bioaerosol plays a number of important
roles related to plant and livestock health, human disease and
allergenicity, and forest and wider ecology and are thought to influence
biosphere–atmosphere interactions via warm and cold cloud formation. Despite
the importance of bioaerosols, there are few measurements of forest aerosol,
and there is a lack of understanding of how climate change will affect
forest bioaerosol in the future.</p>
<p>We installed low-cost optical particle counters (OPCs) to measure particles
in the size range between 1 and 10 <span class="inline-formula">µ</span>m (PM<span class="inline-formula"><sub>10</sub></span>–PM<span class="inline-formula"><sub>1</sub></span>) for a
period of 2 months in autumn 2018 at the Birmingham Institute of Forest
Research (BIFoR) free-air carbon dioxide enrichment (FACE) facility. In the
paper, we propose that the PM<span class="inline-formula"><sub>10</sub></span>–PM<span class="inline-formula"><sub>1</sub></span> (particulate matter) metric is a good proxy for
bioaerosols because of the bioaerosol representative size range, the
location of the study site (a woodland in a rural location), the field
measurement taking place during the season of peak fungal activity, and the
low hygroscopicity of the particles measured. The BIFoR FACE facility
fumigates three 700 m<span class="inline-formula"><sup>2</sup></span> areas of the forest with an additional 150 ppm
CO<span class="inline-formula"><sub>2</sub></span> above ambient levels with minimal impacts on other potential environmental
drivers such as temperature, humidity, and wind. This experimental set-up
enabled us to investigate the effect of environmental variables, including
elevated CO<span class="inline-formula"><sub>2</sub></span> (<span class="inline-formula"><i>e</i></span>CO<span class="inline-formula"><sub>2</sub></span>), on bioaerosol proxy concentrations and to
evaluate the performance of the low-cost OPCs in a forested environment.</p>
<p>Operating the low-cost OPCs during autumn 2018, we aimed to capture
predominantly the fungal bioaerosol season. Across the experimental
duration, the OPCs captured both temporal and spatial variation in
bioaerosol concentrations. Aerosol concentrations were affected by changing
temperatures and wind speeds but, contrary to our initial hypothesis, not
by relative humidity. We detected no effect of the <span class="inline-formula"><i>e</i></span>CO<span class="inline-formula"><sub>2</sub></span> treatment on
total bioaerosol concentrations, but a potential suppression of high-concentration bioaerosol events was detected under <span class="inline-formula"><i>e</i></span>CO<span class="inline-formula"><sub>2</sub></span>. In-canopy
atmospheric dispersion modelling indicates that the median spore dispersion
distance is sufficiently small that there is little mixing between treatment
and control experiments. Our data demonstrate the suitability of low-cost
OPCs, interpreted with due caution, for use in forests and so opens the
possibility of forest bioaerosol monitoring in a wider range of habitats to
a wider range of researchers at a modest cost.</p> |
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| ISSN: | 1726-4170 1726-4189 |