How Driver Alertness Can Be Affected By Poor Air Quality - SGX Sensortech SGX Sensortech

17 September 2015

How Driver Alertness Can Be Affected By Poor Air Quality

For years, the air pollution caused by cars has been discussed with regard to its effects on the environment and health of people outside, such as pedestrians and cyclists. However, the effect it has on the alertness of a driver has not been given much attention.

The fact is that when pollutants enter a car, many undesirable effects can occur that hamper the performance of the driver. The air quality inside cars is gaining a great deal of interest in developed countries, as there are more vehicles and the majority of people use their cars for over an hour a day.

Reasons for Poor Air Quality in Cars

The three key sources that cause a drop in air quality inside cars are explained in the following paragraphs:

Exhaust Fumes

Exhaust fumes, including noxious gases like carbon monoxide (CO), oxides of nitrogen (NOx) and hydrocarbons (HC), can enter the vehicle via heating ventilation and air conditioning (HVAC) systems. These gases are actually present in vehicles at a level beyond the acceptable limits set by the World Health Organisation (WHO).

They can cause breathing difficulties in people with respiratory problems, such as asthma. In elderly people with cardiovascular risk, these gases can even trigger heart attacks. They are also known to cause dizziness, headaches, poor hand-eye coordination and nausea, which all could result in accidents.

Accidental poisoning could be the result of carbon monoxide gas released by cars. Traffic jams are potential scenarios that increase the chances of drivers being exposed to harmful exhaust fumes.

Car Interior Materials

Materials used in the fabrication of the interiors of vehicles, such as the dashboard, seats and steering wheel, can also impact the quality of air within the vehicle. This is because of the use of flame retardants comprising bromine and antimony, PVC to produce the seats, and chromium to treat leather.

All of these can emit volatile organic compounds (VOCs). When cars are parked in the sun, or when temperatures rise due to turning on the heating, the chances for VOC emissions increase. Symptoms, including headaches, dizziness and nausea, can occur due to exposure to VOCs.

Breathing in an Enclosed Environment

Poor air quality can also be the result of the normal breathing process when it happens in an enclosed environment. For instance, in a car with the windows closed and HVAC is being used in recycle mode to stop pollutants from entering the vehicle, oxygen is depleted over time and displaced by carbon dioxide.

According to the Occupational Safety and Health Administration (OHSA) in the US, below 19.5% oxygen concentration is categorized as hazardous. One study revealed that in a car with two people the oxygen levels were found to be just 19.1% after 15 minutes. Increased heart rate and impaired muscle coordination and judgement are experienced by drivers when oxygen levels are depleted.

Similarly, increased carbon dioxide levels may cause drowsiness, leading to fatigue. This is already one of the most serious concerns for road safety. Drivers’ reaction times can become slower, thus making them less alert.

Studies show that nearly 20% of all accidents and a quarter of fatal or serious ones, are caused because of fatigue. Another study showed that in fatal single vehicle crashes most of the cars had the heater on and the windows closed.

Improving Air Quality in Cars

Globally, several efforts have been taken to control pollution from cars. Standards have been established in Europe to limit the emission levels of exhaust gases such as HC and NOx. For instance, in 1992, a Euro standard made it mandatory that all petrol cars have to be fitted with catalytic converters to decrease CO emissions.

More recently, some cars are built with cabin filters often located under the glove compartment to avoid irritants, e.g., pollen, and pollutants from entering the car. This is meant to improve driver comfort, as certain gas fumes cause unpleasant odours.

Manufacturers, such as SGX Sensortech, are developing advanced devices to control air quality. However, these devices are yet to be integrated as a standard component to cars. The Hyundai Genesis Sedan, introduced in 2013, was the first car equipped with an internal carbon dioxide monitor, which is designed to decrease driver drowsiness by allowing fresh air in. Carbon dioxide, which is more often used as a refrigerant gas in air conditioning, can cause asphyxiation if it leaks into the vehicle.

Air quality monitors (AQMs) have also been developed to avoid toxic gas accumulation in cars. The default position of the AQMs is “open,” as their operation is based on controlling the HVAC flaps. However, they shut in response to the detection of increased pollutant levels in the environment. Certain models of AQMs are capable of providing audio and visual alerts when poor air quality is detected.

Similarly, AQMs are also designed to turn off the car engine when CO concentration reaches harmful levels, thereby preventing accidental poisonings and suicides. In the future, AQMs may be incorporated into cars as a common safety feature, much like airbags or seat belts.

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