Recently, a man in Fujian sought medical treatment for difficulty breathing. Examinations revealed his blood oxygen saturation had dropped to as low as 85%, and he was experiencing respiratory failure, ultimately being diagnosed with hypersensitivity pneumonitis.

It is understood that the man had worn a down jacket for over 12 hours daily for four consecutive weeks. The jacket, a low-cost online purchase, had a damaged inner lining, with down fibers floating out from the seams with even slight movement.

Experts from Fujian Provincial People's Hospital stated in an interview that when tiny protein particles from down are continuously inhaled into the alveoli, they can trigger an immune response that attacks lung tissue—even in non-allergic individuals. For this reason, such conditions are also referred to as "down lung."

Experts advise: when purchasing a down jacket, check if the fabric uses down-proof technology; air it out regularly in a well-ventilated area and gently pat it; ensure good air circulation in the environment while wearing it. If symptoms such as progressively worsening dry cough, shortness of breath after activity, or chest tightness occur after wearing specific clothing or being in a certain environment—and relieve after leaving that environment—high vigilance for "down lung" is required.

How to Choose a Down Jacket? Reading the Label is the First Step

Professor Lu Yehhu from the College of Textile and Clothing Engineering, Soochow University, explained in an interview that when selecting a down jacket, focus on several indicators on the label:

Check for compliance with the "New National Standard"According to GB/T 14272—2021 "Down Garments" New National Standard Key Points and Purchase Guide issued by the Standardization Administration of China, down jackets adhering to the new national standard show significant improvements in down quality, down-proof performance, and environmental friendliness compared to products following the 2011 version.

Check the down cluster contentDown clusters are the highest-quality component of down and scientifically proven to be the part that provides warmth. Common down cluster contents on the market are 95%, 90%, and 80%. Generally, higher down cluster content means softer down, higher loft, and better warmth retention under the same conditions.

Note that when fill power is high, the impact of down cluster content becomes complex with smaller differences: "For example, duck down with 80% cluster content and 90% cluster content have nearly identical warmth retention when filled to a certain amount."

Check the fill weight

Fill weight refers to the total weight of all down filled in a jacket, usually measured in grams, and significantly impacts warmth retention.

However, more fill or heavier weight does not equate to better warmth—higher fill density increases heat loss through conduction.

Zhu Wei, Director of the Information Department at the China Feather & Down Industrial Association, provides the following recommended standards:

Lightweight down jackets for early winter: 40–90 grams of fill

Short down jackets of average thickness: approximately 130 grams of fill

Medium-thickness down jackets: approximately 180 grams of fill

Down jackets suitable for outdoor wear in northern China: at least 180 grams of fill

Check the loftLoft measures the ability of down to trap air per unit volume. Higher loft means down can fix a larger air layer with the same fill weight, enhancing insulation and warmth retention. Thus, higher loft indicates better warmth performance.

Down typeDown primarily comes from geese and ducks. Generally, goose down has a higher warmth-to-weight ratio and can be compressed smaller, making it more expensive.

However, "goose down" is not always superior—high-quality duck down may offer better insulation than low-quality goose down. Therefore, when choosing a down jacket, consider both down type and product quality/brand.

Outer fabric

Since down filaments and feather filaments can escape through fabric gaps, the outer material must be dense and wear-resistant to prevent leakage and maintain warmth.

Fabrics treated with water-repellent or waterproof coatings perform better, as they prevent rain/snow from seeping in and keep the down dry and warm.

Additional steps to assess warmth retention:

Press the jacket lightly and observe rebound—quick rebound indicates good loft and warmth.

Feel the texture—softness without coarse feather shafts signifies high quality.

Pat firmly—no dust release means no crushed feathers (a sign of quality).

Rub the fabric—no down leakage confirms down-proof material.

Smell the jacket—strong odors indicate it is unsuitable for wear.

Recently, a man in Fujian sought medical treatment for difficulty breathing. Examinations revealed his blood oxygen saturation had dropped to as low as 85%, and he was experiencing respiratory failure, ultimately being diagnosed with hypersensitivity pneumonitis.

It is understood that the man had worn a down jacket for over 12 hours daily for four consecutive weeks. The jacket, a low-cost online purchase, had a damaged inner lining, with down fibers floating out from the seams with even slight movement.

Experts from Fujian Provincial People's Hospital stated in an interview that when tiny protein particles from down are continuously inhaled into the alveoli, they can trigger an immune response that attacks lung tissue—even in non-allergic individuals. For this reason, such conditions are also referred to as "down lung."

Experts advise: when purchasing a down jacket, check if the fabric uses down-proof technology; air it out regularly in a well-ventilated area and gently pat it; ensure good air circulation in the environment while wearing it. If symptoms such as progressively worsening dry cough, shortness of breath after activity, or chest tightness occur after wearing specific clothing or being in a certain environment—and relieve after leaving that environment—high vigilance for "down lung" is required.

How to Choose a Down Jacket? Reading the Label is the First Step

Professor Lu Yehhu from the College of Textile and Clothing Engineering, Soochow University, explained in an interview that when selecting a down jacket, focus on several indicators on the label:

Check for compliance with the "New National Standard"According to GB/T 14272—2021 "Down Garments" New National Standard Key Points and Purchase Guide issued by the Standardization Administration of China, down jackets adhering to the new national standard show significant improvements in down quality, down-proof performance, and environmental friendliness compared to products following the 2011 version.

Check the down cluster contentDown clusters are the highest-quality component of down and scientifically proven to be the part that provides warmth. Common down cluster contents on the market are 95%, 90%, and 80%. Generally, higher down cluster content means softer down, higher loft, and better warmth retention under the same conditions.

Note that when fill power is high, the impact of down cluster content becomes complex with smaller differences: "For example, duck down with 80% cluster content and 90% cluster content have nearly identical warmth retention when filled to a certain amount."

Check the fill weight

Fill weight refers to the total weight of all down filled in a jacket, usually measured in grams, and significantly impacts warmth retention.

However, more fill or heavier weight does not equate to better warmth—higher fill density increases heat loss through conduction.

Zhu Wei, Director of the Information Department at the China Feather & Down Industrial Association, provides the following recommended standards:

Lightweight down jackets for early winter: 40–90 grams of fill

Short down jackets of average thickness: approximately 130 grams of fill

Medium-thickness down jackets: approximately 180 grams of fill

Down jackets suitable for outdoor wear in northern China: at least 180 grams of fill

Check the loftLoft measures the ability of down to trap air per unit volume. Higher loft means down can fix a larger air layer with the same fill weight, enhancing insulation and warmth retention. Thus, higher loft indicates better warmth performance.

Down typeDown primarily comes from geese and ducks. Generally, goose down has a higher warmth-to-weight ratio and can be compressed smaller, making it more expensive.

However, "goose down" is not always superior—high-quality duck down may offer better insulation than low-quality goose down. Therefore, when choosing a down jacket, consider both down type and product quality/brand.

Outer fabric

Since down filaments and feather filaments can escape through fabric gaps, the outer material must be dense and wear-resistant to prevent leakage and maintain warmth.

Fabrics treated with water-repellent or waterproof coatings perform better, as they prevent rain/snow from seeping in and keep the down dry and warm.

Additional steps to assess warmth retention:

Press the jacket lightly and observe rebound—quick rebound indicates good loft and warmth.

Feel the texture—softness without coarse feather shafts signifies high quality.

Pat firmly—no dust release means no crushed feathers (a sign of quality).

Rub the fabric—no down leakage confirms down-proof material.

Smell the jacket—strong odors indicate it is unsuitable for wear.