Search Climate Insights Directory

The document provides a systematic analysis of how to measure people's thoughts and feelings about migrating. It introduces a conceptual model that deconstructs survey questions into five components: nature of the mindset, temporality of the mindset, nature of the action, temporality of the action, and conditionality. Through a review of over 50 surveys and field testing in Cabo Verde, the author argues that binary questions are generally more reliable than open-ended or scale-based ones and emphasizes the importance of distinguishing between preferences, expectations, and considerations of migration.

The document reports that engine crankcase emissions are the primary source of PM2.5 mass in conventional school bus cabins, while the tailpipe is the main source of ultrafine particles, black carbon, and particulate polycyclic aromatic hydrocarbons. Research across four US cities indicates that while diesel particulate filters (DPFs) and ultra-low sulfur diesel (ULSD) reduce ultrafines and black carbon to ambient levels, they do not significantly reduce PM2.5. The installation of a closed-crankcase filtration device, specifically the Donaldson Spiracle™, was found to be critical and necessary to reduce cabin PM2.5 levels to near ambient levels across all tested bus and fuel combinations.