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.

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.

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.

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:

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:

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:

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.