If you walk along a busy road, you are likely to inhale vehicle exhaust. Surprisingly, drivers and passengers in passing cars are breathing even more polluted air. Toxic air pollutants like carbon monoxide and nitrogen oxides don’t simply float outside in the atmosphere; they can be found in high concentrations inside cars, posing a serious health risk.
By design, vehicle ventilation systems take in emissions from surrounding vehicles and recirculate them, drawing pollutants into the car cabin. When vehicles are in traffic, especially when surrounded by larger polluting vehicles such as diesel trucks, cabin pollutant concentrations can reach levels damaging to human health.

Air pollution levels are remarkably high at busy intersections with traffic signals because drivers decelerate, idle, and accelerate there. The same situation occurs everywhere wherever cars idle, such as drive-through windows at restaurants or at school drop-offs and pick-ups.
Vehicle exhaust is a mixture of volatile organic compounds (VOCs), nitrogen oxides (NOx), particulate matter (PM), carbon monoxide (CO) and sulphur oxides (SOx). Recurring exposure to this noxious cocktail of gases is responsible for a range of health impacts including breathing problems, allergies, asthma, bronchitis, cardiovascular problems and heart failure to name a few.
There are several ways to minimize the concentration of toxic pollutants inside your car:
- Change the cabin air filter at least once every year as a best practice. Cabin filters can filter out larger particles like pollen and dust.
- Use a strong in-car air purifier. This will supplement your cabin filtration system and reduce PM, VOCs, CO and other pollutants. It will also filter air entering your car cabin through windows and door cracks.
- Use public transit or active transportation options to avoid driving during rush hour.
- While driving, keep some distance from vehicles ahead of you, especially from high polluting vehicles like diesel trucks.
- If you are stuck in traffic or waiting at a red light, close your windows, maintain a safe distance from the vehicle in front of you, and switch your air conditioner on to recirculate for a few minutes.
- Keep the interior clean. Use a microfiber cloth to wipe surfaces. Avoid chemical cleaners. Vacuum upholstery and carpeted floor and mats regularly to reduce dust particles.
- Avoid using air fresheners as they release harmful VOCs and make your air quality worse instead of better. Switch to natural products like herbs and essential oils instead.
In the long run, one of the most effective ways to reduce exhaust pollution is switching to an Electric Vehicle (EV) or Plug-in Hybrid Electric Vehicle (PHEV) when upgrading your car. EVs running on electricity generated by non-polluting renewable sources have minimal life-cycle emissions. PHEVs are more efficient than conventional cars operating on gasoline, and they produce fewer tailpipe emissions even when relying on gasoline. Clean Air Partnership promotes the adoption of EVs through projects like Accelerating EV Uptake.
By Devanshi Kukadia, Research and Communications Manager, Clean Air Partnership.