HEALTH EFFECTS OF POLLUTION

It is all too easy to ignore the e ects of pollution in Palo Alto. With the city’s extensive greenery and high air quality, pollution often exists as a distant issue in people’s minds rather than an immediate cataclysm. In most urban cities, however, pollution is becoming an exigency: It increases respiratory infections, heart disease, and lung cancer while rapidly changing urban landscapes.

Pollution predominantly takes the form of particulate matter, or small mixtures of chemicals that vary in size, composition, and shape and contain metallic compounds and elemental carbon. The most worrying forms of PM are PM10, matter with a diameter of 10 or fewer microns, and PM2.5, matter with a diameter of 2.5 or fewer microns. When breathed in, PM10 can deposit itself in the upper respiratory regions and large airways in the lungs, but will remain in the upper areas of the lungs. PM2.5, however, can lodge itself much further into the lungs. This blockage has been shown to lead to acute or chronic bronchitis, lung cancer, increased and more intensive asthma attacks, and premature mortality. All of these disproportionately impact children, the elderly, and those with preexisting respiratory conditions.

Particulate matter is mainly produced by cars, buses, and factory emissions. It di ers from carbon dioxide, however, in that it can also come from construction sites, tilled fields, freshly unpaved roads, and even rock slides. Because of the greater concentration of transportation and factories in urban areas, cities have higher levels of PM buildup, resulting in a greater risk of respiratory issues in these areas. PM also creates visibility issues because it alters the way light is absorbed and scattered in the atmosphere—some particulate matter is large enough to be seen as soot or smoke in the air. Particulate matter also a ects rural landscapes, especially agricultural areas. When deposited in the ground, PM can reduce soil’s ability to raise organic compounds, impacting not only farmland but also natural ecosystems: PM decreases the amount of nutrients for animals to consume, limiting the growth of the environment. Pollution greatly a ects all aspects of our life and demands immediate attention, no matter how little individuals may think it a ects them.

—Written by Aarushi Kumar, a STEM Editor.