Air pollution refers to the presence of harmful substances, such as gases, particulates, and biological molecules, in the Earth’s atmosphere. Air pollution can have serious negative impacts on human health, as well as the environment. It has been linked to a wide range of health problems, including respiratory and cardiovascular disease, cancer, and other illnesses.
According to the World Health Organization, over 4.2 million people die prematurely each year due to long-term exposure to fine particulate outdoor air pollution, also known as PM. However, a recent study involving researchers from McGill University suggests that this number may be underestimated. The study found that mortality risk was increased even at very low levels of PM, levels that were previously not considered dangerous.
The WHO recently set out ambitious new guidelines for annual average outdoor fine particulate air pollution, cutting its earlier recommendations in half, from concentrations of 10 to concentrations of 5 micrograms per cubic meter. The current United States Environmental Protection Agency standard of 12 per cubic meter is now more than double the value recommended by the WHO.