Headlines proclaiming COVID lockdowns drastically reduced pollution were mostly referring to nitrogen dioxide, NO2, a reactive gas emitted from burning fuel. There had been less understanding of how lockdowns affected PM2.5, tiny particulate matter that can penetrate a person’s lungs, leading to a host of health problems, including increased risk for heart attack and cancer.
Click here for original story, Pandemic air quality due to weather, not just lockdowns
Source: Phys.org