EXPLAINER

While AC keeps us cool, it can also cause dry skin and irritation. Here are some tips to keep comfortable this summer.

Summer is here and temperatures are rising across the Northern Hemisphere, where nearly 90 percent of the world’s people live. The heat is pushing people to rely on air conditioners to stay comfortable.

While air conditioners provide relief from extreme heat, they also remove moisture from the air, which can cause skin dryness and irritation.

In this visual explainer, Al Jazeera breaks down how air conditioners work, what they can do to your health and practical tips to protect yourself while you stay cool.

How does an air conditioner work?

Air conditioners work by removing heat and moisture from indoor air and releasing it outside.

The process starts when the indoor unit pulls in warm air and sends it over cold evaporator coils. Inside the coils, liquid refrigerant absorbs the heat, evaporates into a gas and cools the air. A fan then blows the cooled air back into the room.

The now-warm refrigerant gas travels to an outdoor unit, which releases the heat through a condenser coil that turns it back into a liquid.

The liquid refrigerant returns indoors to repeat the cycle.

When was AC invented?

The invention of modern air conditioning is generally credited to the American engineer Willis Carrier, who in 1902 designed a humidity-control system for a New York printing plant using chilled coils.

Window-mounted units followed in 1931, and after World War II, mass production brought AC into homes and offices.

By the 1990s, growing environmental concerns led to the phaseout of ozone-depleting chlorofluorocarbons, or CFCs, in favour of hydrofluorocarbons (HFCs).

In the 2010s, newer refrigerants, such as R-32 and R-290 (propane), marked a shift towards lower-emissions cooling.

Where is air conditioning needed most?

As temperatures rise, more countries around the world are increasingly adopting air conditioners. Without effective or accessible cooling, many people may be exposed to heat stress and related illnesses.

According to the World Health Organization, heat stress is the leading cause of weather-related deaths and can exacerbate underlying illnesses, including cardiovascular disease, diabetes, mental health issues and asthma, as well as increase the risk of accidents and the transmission of a number of infectious diseases.

The regions with the highest heat stress are generally those that have a combination of high temperatures, high humidity and intense sun exposure.

Heatstroke is the most extreme form of heat stress – a severe medical condition that occurs when a body’s internal temperature exceeds 40 degrees Celsius (104 degrees Fahrenheit) – and can be life-threatening if not treated immediately.

The graphic and list below summarise 10 tips to help minimise the risk of heatstroke:

1. Drink plenty of water.
2. Wear sunblock.
3. Wear cotton and loose clothing.
4. Never leave anyone in a parked car.
5. Stay away from direct sun exposure, especially in the afternoons.
6. Avoid exercise during the hottest part of the day.
7. Ventilate and cool your living space.
8. Take cool showers.
9. Eat lightly.
10. Take precautions with medications.

How to treat someone with heatstroke

If you or another person is experiencing heatstroke symptoms, such as rapid heartbeat, rapid breathing, high body temperature, dehydration or nausea, here are a few steps to bring down body temperature while waiting for emergency medical aid:

1. Get out of direct exposure to the sun.
2. Lie down and elevate your feet.
3. Take off tight clothing.
4. Use a fan or air conditioner to lower body temperature.
5. Apply cold compresses.
6. Drink lots of fluids.

What does air conditioning do to the body?

While air conditioners keep us from overheating, long-term use as well as poor maintenance can lead to adverse effects on the body.

Here are some ways air conditioners can affect different parts of the body along with some practical remedies:

1. Dry skin and eyes: AC strips moisture from the air, leaving skin tight and flaky and eyes irritated or itchy. Combat this by using a moisturiser regularly and keeping lubricating eye drops on hand.
2. Headaches: Prolonged exposure to cold, dry air can trigger tension headaches, which are often worsened by dehydration. Drink water consistently throughout the day and take breaks from heavily air-conditioned spaces when possible.
3. Dry nose and throat: The low humidity in AC environments dries out mucous membranes, causing soreness, congestion or a scratchy throat. A saline nasal spray or throat lozenges can provide quick relief, and a humidifier helps in the long term.
4. Respiratory irritation: Poorly maintained AC units circulate dust, mould spores and bacteria, aggravating the airways and worsening conditions like asthma. Clean or replace filters regularly, and ensure the unit is serviced at least once a year.
5. Muscle stiffness and joint pain: Cold air causes muscles to contract and tighten, particularly in the neck, shoulders and back. Gentle stretching, staying warm with a light layer and avoiding sitting directly under a vent can ease the discomfort.
6. Sleep: A cool room supports deeper sleep by lowering core body temperature, but air that is too cold or too dry can cause disruptions. For most people, setting the thermostat between 16C and 18C (60-65F) and using a light blanket strikes the right balance.

How to build a homemade air cooler

If you don’t own an air conditioner or are trying to save on energy costs, here are some steps you can follow to build a do-it-yourself cooler out of a styrofoam cooler, ice and a fan.

While this won’t necessarily help with the humidity, it can provide temporary relief during the hottest summer days.