Car air conditioning offers health benefits but requires proper maintenance, Armenian experts say

Vehicle air conditioning systems can help protect drivers and passengers from heat-related illness and improve road safety, but poor maintenance and improper use may also pose health risks, according to a review of medical evidence highlighted by Armenia's Yerevan State Medical University.

The university said its Heratsi Research Center had compiled scientific and practical findings on the health effects of car air conditioning, outlining both its benefits and potential hazards.

Medical experts say air conditioning does more than simply cool a vehicle. By reducing temperatures inside cars, which can exceed 50 degrees Celsius in hot weather, it can lessen strain on the cardiovascular system and reduce the risk of heatstroke and heat-related complications.

Modern cabin air filters, particularly high-efficiency particulate air (HEPA) and activated carbon filters, can also reduce exposure to dust, pollen, soot and traffic-related pollutants, providing relief for people with allergies or asthma who might otherwise be exposed while driving with the windows open.

Maintaining a comfortable cabin temperature may also improve road safety by reducing driver fatigue, drowsiness and impaired concentration caused by excessive heat.

However, the university said most health risks associated with vehicle air conditioning arise from inadequate maintenance or improper operation.

Moisture that accumulates on the system's evaporator can encourage the growth of mould and bacteria. Among the microorganisms that can colonize poorly maintained systems is Legionella pneumophila, the bacterium that causes Legionnaires' disease, a severe form of pneumonia. A persistent musty odour when the air conditioner is switched on may indicate microbial contamination.

Air conditioning can also dry the cabin air, potentially causing irritation of the eyes, throat and skin, particularly for contact lens wearers.

The review also noted that moving abruptly from extreme outdoor heat into a very cold vehicle can place stress on the body. Cold air directed continuously at the face, neck or back may contribute to muscle stiffness or nerve irritation.

The university also addressed a long-circulating claim that heated plastics inside vehicles release dangerous levels of benzene, making it unsafe to switch on the air conditioner immediately after entering a hot car.

It said studies, including research published in Toxicology Letters and findings cited by the Society of Automotive Engineers, have found benzene concentrations inside heated vehicles to be well below levels associated with poisoning. Even so, experts recommend ventilating a parked vehicle by opening its windows for one to two minutes before turning on the air conditioner.

The review also cited research published in Environmental Science & Technology showing that prolonged use of a vehicle's air recirculation mode can increase carbon dioxide concentrations inside the cabin, potentially contributing to fatigue. It recommended periodically allowing fresh air into the vehicle during longer journeys.

To reduce health risks, the university advised motorists to replace cabin air filters every 10,000 to 15,000 kilometres, disinfect the air conditioning system annually and switch off the air conditioning compressor two to three minutes before reaching their destination while leaving the fan running to help dry the system and reduce moisture buildup.