Dr Koh Hong Yi on Effect of Haze on the Skin | Channel 8 Talk of the Town

September 2026

Key Takeaways (English)

The haze is back this year with vengeance. While everyone is tracking the PSI and PM2.5 indices like a hotly traded stock and snatching up face masks to protect our airways, we may be neglecting the effects of the haze on our skin. In this episode of Channel 8’s Talk of the Town, senior consultant dermatologist Dr Koh Hong Yi (许弘毅) and beauty and personal-care product expert Ms Hong Beilei (洪蓓蕾) discuss how Singapore's climate and the current haze situation impacts our skin, especially those with pre-existing skin conditions such as eczema. Dr Koh also shares practical tips on skin care, and answers burning questions like whether people with oily skin really needs moisturisers even in Singapore’s hot and humid climate.

● The haze is our skin’s silent killer. Unlike the sun and heat which trigger visible responses on our skin such as redness and tanning, the effects of airborne pollutants such as PM2.5, PM10 particles are more insidious and even deadly. Air pollution damages the skin barrier, causes oxidative stress and increases inflammation in the skin. Numerous studies show that rates of eczema, psoriasis, acne and even hair loss increase when air quality decreases.

● Sunscreen is important even on cloudy or hazy days. UV rays can still reach the skin when the sun is not visible. In fact, the cloud and haze may give one a false sense of security to omit sun protection. SPF 30 is a reasonable starting point for daily use, while SPF 50 or higher may be beneficial for prolonged outdoor activities. Applying enough sunscreen and reapplying when necessary are equally important.

● Expensive skincare products are not necessarily better. A study published in JAMA Dermatology in 2017 compared 174 best-selling skin care products, and was unable to demonstrate superiority of any particular product despite price differences up to 9400%ⁱ. A product's effectiveness depends more on its formulation, ingredients and suitability for one’s skin type than its price. A product's effectiveness depends more on its formulation, ingredients and suitability for one’s skin type than its price.

● A few key ingredients form the backbone of anti-skin aging. Retinoids have robust evidence demonstrating ability to combat skin aging, appearance of fine lines, pigmentation and even skin cancer. Vitamin C, via its antioxidant effects, can address uneven skin tone and delay the effects of UV radiation on the skin. Dr Koh and Ms Hong coined the phrase “Morning C, Evening A” as a memory aide to how these products should be used. Together with moisturizers and sunscreens, they form the pillars of skin rejuvenation and anti-aging.

● Moisturising remains important in Singapore's humid climate, and even if one has oily skin. Studies have shown that people with increased sebum product may also have increased trans epidermal water loss (TEWL), which is a marker of a damaged skin barrier. Hence having oily skin and impaired skin barrier are not mutually exclusive. The right question to ask is not whether one should use a moisturiser or not if one has oily skin, but what is the right moisturiser with the appropriate texture and ingredients suitable for one with oily or combinational type skin.

节目重点摘要（中文）

烟霾今年卷土重来，来势汹汹。当大家像紧盯热门股票一样追踪PSI和PM2.5指数、抢购口罩保护呼吸道时，我们或许忽略了烟霾对皮肤的影响。在本集8频道《狮城有约》节目中，皮肤科高级顾问许弘毅医生与美容及个人护理产品专家洪蓓蕾女士，探讨新加坡的气候和当前的烟霾状况如何影响我们的皮肤，尤其是原本就患有湿疹等皮肤病的人群。许医生也分享了实用的护肤建议，并解答大家最关心的问题，例如：油性皮肤的人在新加坡湿热的气候下，是否真的需要使用保湿霜？

● 烟霾是皮肤的"隐形杀手"。
阳光和高温会让皮肤出现发红、晒黑等明显反应，而PM2.5、PM10等空气污染颗粒对皮肤的影响则更隐蔽，甚至更具破坏性。空气污染会损害皮肤屏障，引发氧化应激，并加剧皮肤炎症。大量研究显示，空气质量下降时，湿疹、银屑病（牛皮癣）、痤疮（暗疮）乃至脱发的发病率都会上升。

● 即使是阴天或烟霾天，防晒依然重要。
即使看不见太阳，紫外线仍然能照射到皮肤。事实上，云层和烟霾反而可能让人产生错误的安全感，从而忽略防晒。日常使用SPF 30是一个合理的起点；若长时间进行户外活动，SPF 50或以上可能更有益。涂抹足量的防晒霜，并在必要时补涂，同样重要。

● 护肤品并非越贵越好。
2017年发表于《JAMA皮肤病学》（JAMA Dermatology）的一项研究比较了174款畅销护肤品，发现尽管价格差距高达9400%，却无法证明任何一款产品具有明显优势。[ⁱ] 一款产品是否有效，更取决于其配方、成分以及是否适合个人肤质，而非价格。

● 几种关键成分是抗衰老的基石。
维A酸类（视黄醇类）成分有充分的证据显示能对抗皮肤老化，改善细纹、色斑，甚至有助预防皮肤癌。维生素C则通过其抗氧化作用，改善肤色不均，并延缓紫外线对皮肤造成的伤害。许医生和洪女士提出了"早C晚A"这一口诀，帮助大家记住这些产品的使用方法。它们与保湿霜和防晒霜一起，构成了肌肤焕活与抗衰老的四大支柱。

● 即使在新加坡潮湿的气候下，即使是油性皮肤，保湿依然重要。
研究显示，皮脂分泌旺盛的人，经表皮水分流失（TEWL）也可能增加，而这正是皮肤屏障受损的指标。因此，油性皮肤与皮肤屏障受损并不矛盾，两者可以同时存在。真正该问的问题，不是油性皮肤要不要用保湿霜，而是哪一种保湿霜的质地和成分适合油性或混合性肌肤。

References:

[1] Xu S et al. Consumer preferences, product characteristics and potentially allergenic ingredients in best-selling moisturizers. JAMA Dermatol 2017;153;(11):1099-1105