The airflow rate among rechargeable portable fans can vary by more than 1.5 times, a study by Hong Kong’s consumer watchdog has found. The Consumer Council, which tested 16 handheld and two neck-mounted products, found that among the lighter handheld models it examined, there was a variance of more than 1.5 times. The discrepancy among the heavier models could be more than 1.3 times. “It is worth noting that among models with similar fan head size, the air flow can still vary considerably,” the...