Group 1 - A man in Fujian was diagnosed with allergic pneumonia after wearing a low-cost down jacket for over 12 hours daily for four weeks, leading to a blood oxygen saturation level of 85% and respiratory failure [1] - Experts warn that inhaling micro-protein particles from down can trigger immune responses even in non-allergic individuals, a condition referred to as "down lung" [1] - Recommendations for purchasing down jackets include checking for anti-leak technology in the fabric, airing out the jacket regularly, and ensuring good air circulation while wearing [1] Group 2 - When selecting down jackets, consumers should pay attention to labels, particularly those adhering to the new national standard GB/T 14272-2021, which indicates improved quality in down quality, anti-leak properties, and environmental performance compared to the 2011 standard [3] - The down content is crucial, with higher down content (95%, 90%, 80%) generally providing better warmth and softness, although the difference in warmth may diminish at higher fill weights [4] - Fill weight, measured in grams, significantly impacts the warmth of a down jacket, but more fill does not always equate to better insulation due to increased heat loss with higher density [4] Group 3 - Loftiness, which measures the ability of down to trap air, is essential for insulation; higher loftiness means better warmth retention [6] - Recommendations for fill weights vary by jacket type, with lightweight jackets suggested to have 40-90 grams, standard jackets around 130 grams, and those suitable for northern outdoor wear at least 180 grams [5] - The type of down, whether from geese or ducks, affects insulation quality, with high-quality duck down sometimes outperforming low-quality goose down [7] Group 4 - The outer fabric of down jackets should be dense and durable to prevent down leakage, and water-resistant treatments enhance performance by keeping the down dry [8]

Core Viewpoint - The article highlights consumer dissatisfaction regarding a down jacket purchased online, which was marketed as a "down jacket" but contained only 5.4 grams of down filling, raising concerns about product labeling and quality standards [1] Group 1: Product Quality and Standards - The down filling amount in the jacket is significantly lower than typical outdoor down jackets, which usually have a filling weight between 250 to 450 grams [1] - The China Down Industry Association recommends that outdoor down jackets in northern regions should have a minimum filling weight of 180 grams [1] Group 2: Consumer Experience - A consumer reported their experience of purchasing the jacket for 345 yuan, expressing disappointment upon discovering the low down filling amount [1] - The seller acknowledged the low filling amount, stating that it is concentrated in specific areas of the jacket, suitable for temperatures between 0 to -5 degrees Celsius [1]