Can cooking photoage you?
I do enjoy cooking, when it is done for pleasure and not in a mad rush after work with a time pressure looming over my head. It was therefore dispiriting to read earlier in March that gas hobs can raise indoor air pollution to higher than that found on a busy UK road.
What study was this?
This was a small study by Which? In which they gave air quality monitors to five volunteers – four of whom had gas hobs and one with an induction hob – and asked them test the air quality in their homes during normal usage and in a variety of cooking scenarios with the windows and doors shut on all occasions except one.
What did they find?
They found that the levels of nitrogen dioxide (NO2) rose with the use of a gas hob, the levels depending on the time the gas was used for and the number of gas rings used, whereas the levels of NO2 with the induction hob were that of background levels.
The levels of PM2.5, or fine particulate matter 2.5, is a type of air pollution composed of tiny particles less than 2.5 microns in width. It comes from burning combustion fuels such as petrol and diesel, industrial emissions, burning wood and cooking.
They found peak levels of PM2.5 of over 100 microgram/m3 with a peak of nearly 650 microgram/m3 with one volunteer frying peppers, and nearly 500 when cooking a fry-up. The levels remained elevated for a long time in the kitchen and adjacent rooms.
What was the background levels?
They did test the levels near the Which? Office on Marylebone Road, London and found the average PM2.5 over a 24-hour period in November 2024 to be 14 micrograms/m3.
What can be done to reduce this?
In all experiments, an extractor hood was used. However, if the kitchen was fully ventilated with all windows and external doors open during cooking and for 10 minutes afterward, the levels of PM2.5 rose by far less. The average peak was 27 micrograms/m3. PM2.5 levels also returned more quickly to pre-cooking levels if the doors and windows were open.
This is only one small study though…
That is true but there is a lot of evidence to back it up.
[Jaffe DA & Creekmore A. Emissions and exposure to NOx, CO, CO2 and PM2.5 from a gas stove using reference and low-cost sensors. https://doi.org/10.1016/j.atmosenv.2024.120564]
So what has this got to do with the skin?
There have been numerous studies looking at the effect of pollution on skin diseases such as eczema, psoriasis and acne.
[Paik K, Na J-I, Huh C-H et al. Particulate Matter and Its Molecular Effects on Skin: Implications for Various Skin Diseases. Int. J. Mol. Sci 2024;25(18):9888; https://doi.org/10.3390/ijms25189888]
However, the most convincing evidence is the link between environmental pollutants and skin aging, in combination with ultraviolet radiation and oxidative stress.
[Vierkotter A, Schikowksi T, Ranft U et al. Airborne particle exposure and extrinsic skin aging. J. Investig. Dermatol. 2010 ;130 :2719-2726.]
[Huang CH, Chen SC, Wang YC et al. Detrimental correlation between air pollution with skin aging in Taiwan population. Medicine 2022; 101: e29380]
How does pollution cause skin aging?
It mostly in promoting wrinkle formation and causing pigmentary changes.
It is thought that wrinkles are promoted because when the skin cells (or keratinocytes) are exposed to particulate matter (PM), it causes inflammation. These inflammatory signals activate neighbouring fibroblasts (the cells that make collagen) and the release of various cell signalling molecules that cause collagen breakdown, breakdown of the extracellular matrix and thereby loss of skin integrity.
[Paik K, Na J-I, Huh C-H et al. Particulate Matter and Its Molecular Effects on Skin: Implications for Various Skin Diseases. Int. J. Mol. Sci 2024;25(18):9888; https://doi.org/10.3390/ijms25189888]
PM also causes an increase in melanin pigmentation which is exacerbated by sun exposure. Light-excited PM2.5 was also found to generate reactive oxygen species in human keratinocytes which may lead to damage to skin cells.
[Mokrzyński K, Krzysztyńska-Kuleta O, Zawrotniak M et al. Fine Particulate Matter-induced Oxidative Stress Mediated by UVA-Visible Light leads to Keratinocyte Damage. Int J Mol Sci 2021;22(19):10645]
So should I get rid of my gas cooker?
Well, I love my gas hob so I won’t be ditching it in a hurry. But I think I will be opening up the windows and doors when I cook and applying a good facial SpF50 before I go outside!
Kind regards,
Sandy
Dr Sandy Flann, Consultant Dermatologist
