No abstract

The mapping of field boundaries can provide important information for increasing food production and security in agricultural systems across the globe. Remote sensing can provide a viable way to map field boundaries across large geographic extents, yet few studies have used satellite imagery to map boundaries in systems where field sizes are small, heterogeneous, and irregularly shaped. Here we used very-high-resolution WorldView-3 satellite imagery (0.5 m) and a mask region-based convolutional neural network (Mask R-CNN) to delineate smallholder field boundaries in Northeast India. We found that our models had overall moderate accuracy, with average precision values greater than 0.67 and F1 Scores greater than 0.72. We also found that our model performed equally well when applied to another site in India for which no data were used in the calibration step, suggesting that Mask R-CNN may be a generalizable way to map field boundaries at scale. Our results highlight the ability of Mask R-CNN and very-high-resolution imagery to accurately map field boundaries in smallholder systems.

The recent increase of fine particulate matter in Bangkok, Thailand has become a widespread public health concern. Wearing a particulate respirator is one method to reduce particulate inhalation and therefore mitigate the adverse health effects of ambient air pollution. This study provides an integrated assessment of seven particulate respirator models based on three criteria: effectivity, cost, and environmental impact. The overall effectivity of each model is evaluated by assessing the product’s features associated with facial fit. The cost criterion reflects current market prices for bulk and individual orders. Thirdly, an environmental impact score is determined for the product life cycle of each respirator using life cycle assessment. The study assesses each respirator as it would be manufactured, distributed, used, and disposed of in Bangkok, Thailand. The integrated assessment results in twelve distinct consumer frameworks, reliant on variations of the three criteria, to provide guidance for policy makers and independent consumers in the selection of particulate respirators to optimally suit their needs. Ultimately, the data suggest that a buyer’s ideal respirator choice for short-term use is a disposable particulate respirator with a head strap. For long-term use, the study recommends a low-cost reusable respirator with an exhalation valve and replaceable filters. The average effectivity of reusable respirators is found to be greater than that of disposable respirators, due to their higher average number of available sizes. Reusable respirators are associated with consistently lower environmental impacts. The short-term cost of disposable respirators is much less than those of reusable models, however prices do converge over time.