Calima in Tenerife: how to protect your phone and laptop from Saharan dust

Calima is the name used in the Canary Islands for episodes of Saharan dust in the air. Spain's state weather agency AEMET describes how dust storms over the Sahara send waves of mineral dust out over the Atlantic; when a strong intrusion reaches the islands they sit under a haze of atmospheric dust, and suspended dust worsens air quality and raises PM10 and PM2.5 particle levels.

AEMET treats suspended dust as adverse weather and can issue a yellow warning when visibility is expected to drop below 3,000 metres, while the Canary Islands Government declares pre-alerts for calima during strong episodes. AEMET's blog describes, for example, an intense episode in February 2021 caused by a strong Saharan dust intrusion. For electronics the problem is simple: very fine powder that gets into anything with a fan, a grille or a port.

It clogs the cooling system. A laptop pulls air in through its vents to cool the processor, and during a Calima episode that air carries fine mineral dust. It packs into the heatsink fins, coats the fan blades and settles on the board. Airflow drops, the fan spins faster and louder, the laptop runs hot, slows itself down to protect the processor and, in bad cases, switches off.

Apple explains that vents let a laptop's fans draw in cool air and push out hot air, so they should be kept clear, and that a laptop used on a soft surface such as a bed, a sofa or your lap makes the fans work harder. Dust does the same from the inside. It is the main laptop problem A1 Computers sees in the south of Tenerife, as our laptop repair guide describes.

It works its way into the openings. Fine Saharan powder settles in speaker grilles, microphones and the charging port, so audio sounds muffled, buttons feel gritty and charging can become unreliable. Phones rated against dust resist it better, but Apple says splash, water and dust resistance are not permanent and can decrease with normal wear, so an older or repaired phone is less protected.

On iPhones, A1 Computers mostly sees Calima as muffled audio and flaky buttons; in the charging port it mixes with beach sand. Treat a dusty port gently: phone not charging has the cleaning steps Apple, Samsung and Google recommend.

Wipe it, don't blast it. Apple's advice for an iPhone that has been in contact with dirt or sand is to unplug it, switch it off and clean it with a soft, slightly damp, lint-free cloth, keeping moisture out of the openings. Apple says not to use compressed air on an iPhone and not to push objects into its ports.

For the charging port, Samsung suggests switching a Galaxy off and removing debris with a soft brush or by gently blowing air into it, and Google says to tap a Pixel against your hand with the port facing down. Leave speaker and microphone grilles alone: dust packed inside them is removed with the phone open on the bench, where it can't be pushed further in.

Clean the outside yourself and leave the inside to someone who can open the laptop safely. Switch the laptop off and unplug it first. For a MacBook keyboard, Apple's own method uses compressed air: hold the laptop at a 75-degree angle, spray from left to right with the straw about 1.3 cm (half an inch) from the keys, then repeat with the laptop turned on its right side and on its left side. Don't turn the can upside down while spraying.

Keep the vents clear and use the laptop on a hard, flat surface, as Apple advises. Dust already packed into the fan and the heatsink needs the laptop opened: the fan is cleaned, the heatsink fins are cleared and, where dust has reached the board, the board is cleaned too, ultrasonically if it is contaminated. A1 Computers does this for Windows laptops and MacBooks at Local 4, CC San Eugenio, Costa Adeje.

Keep the dust out in the first place. The Canary Islands Government's health advice during Calima is to stay indoors as much as possible, keep the windows closed and wipe dusty surfaces with damp cloths, and the same habits protect electronics:

• Close the windows and balcony doors while the dust is heavy.
• Put phones, tablets and cameras away in a bag, a drawer or a case when you aren't using them.
• Close the laptop lid when it isn't in use, and don't run it on a towel or a bed.
• Wipe surfaces with a damp cloth rather than brushing the dust into the air.
• Watch the forecast: AEMET's warnings and the Canary Islands Government's pre-alerts tell you when an episode is coming.

When the fan stays loud even though the laptop is doing very little, the base gets hot, or the laptop slows down or switches itself off under load. Apple notes that fans speed up during heavy tasks such as video exports or games, which is normal; a fan running fast while the laptop is idle and well ventilated points to a problem. On an Intel Mac, Apple suggests resetting the SMC first, and on a Mac with Apple silicon, closing and reopening the lid or restarting.

If that doesn't help, the cooling system needs cleaning. Ask for a price on WhatsApp at 641 780 077 with the make and model, or bring the laptop and its charger to Local 4, CC San Eugenio, Costa Adeje. There is no branch in Los Cristianos: laptops from the whole south coast come to the same bench.