Outdoor air quality has really declined in recent days in the Northeast due to raging forest fires in parts of eastern Canada. Not only can you visually see reduced visibility on the horizon, but at times you can actually smell smoke in the air despite being hundreds of miles from the sources of the fires. I use the AirVisual app on my phone to alert me about the severity of the air quality. The fires are regularly causing levels of PM2.5 particles in the air to spike above 150 µg/m3, which can be harmful to human health in prolonged exposure.
This is a PSA to owners of recent Tesla cars. Not only are your electric cars not contributing to air pollution, but Models Y, S, and X have unusually large in-cabin HEPA air filters that do a very good job of blocking PM2.5 particles from entering the car.
You are safer from wildfire pollutants sitting inside your car with HVAC running than rolling down the windows. But these recent Teslas can go a step further on particularly dirty days like today. A dedicated “Bioweapon Defence” mode is available in the HVAC settings screen that takes inspiration from hospital cleanrooms and builds positive pressure inside the cabin to prevent external dirty air from leaking in. Although the HVAC system will use considerably more energy while operating in this mode, it is a small price to pay for a breath of clean air.
Here is a more technical explanation from Tesla on how the powerful HEPA filter system works.