Whilst the quality of air in the Bay Area is of relatively good quality in comparison to global locations, and San Francisco’s annual (2019) PM2.5 level of 7.1 μg/m3 achieves the World Health Organisation’s target level of 10 μg/m3, the WHO emphasizes that even at low levels, there is no known “safe” limit for particle pollution below which no negative health impacts may be observed. Therefore, it is in the interests of San Francisco and Bay Area residents to minimize both air pollution emissions, and human exposure to the the present air pollution, as much as possible.
Furthermore, during instances of higher pollution levels, either due to vehicular activity or the occurrence of a forest fire (or a combination of both), pollution levels can quickly climb to the point where they become to have the potential to cause several negative effects upon inhalation. These health effects can include increased risks of lung cancer, chronic obstructive pulmonary diseases, an umbrella term that refers to a variety of respiratory ailments such as emphysema and bronchitis, as well as the aggravation of existing conditions such as asthma.
Other issues related to the breathing of burnt organic matter can include permanent reduction in lung capacity, which has the ability to stunt growth in young children as well as causing cognitive defects. Pregnant women can risk their baby’s health when breathing such air, with incidences of miscarriage, low birth weight and birth defects all being possible, with their chances of occurring rising in correlation with pollution levels going up.
With a wide variety of health issues possible during months of higher pollution, preventative measures become much more important in nature, with the wearing of high-quality particle filtering masks and avoiding outdoor activities and exercise during days of heightened pollution all being good practices that can help in reducing the health consequences to the citizens of the Bay area.