Three year average ozone concentrations within the central Arizona-Phoenix area, period 2003 to 2005

These data is part of the effort to provide the most detailed data on air quality in CAPLTER. This dataset represents spatially interpolated ozone (O3) levels as measured by monitroring stations of the Maricopa County Air Quality Department. O3 is a naturally occurring compound in which three oxygen atoms combine together. This is an unstable combination, and ozone is continually going through a natural cycle of being formed and then converting back to the more stable 'normal' double oxygen compound (O2). The cycle occurs fairly rapidly. In the stratosphere (6 miles and more above the earth), naturally occurring ozone has a beneficial effect of screening out harmful ultraviolet light from the sun. However, ground-level ozone is a pollutant and is a major component of the brown haze that is often observed in the Maricopa County valley. Ozone is not directly emitted into the air, but rather forms in a complex reaction that involves heat, sunlight, and a 'soup' of toxic pollutants, especially volatile organic compounds (VOCs). Some of the most common sources of VOCs are gasoline vapors, chemical solvents, and combustion products of fuels and consumer products. Ozone is created by sunlight acting on nitrates (NOX) and VOCs from motor vehicles and stationary sources, and can be carried hundreds of miles from their origins. Ozone affects the respiratory system in people and animals, and also affects the growth of plants.

本数据集是为CAPLTER区域提供最详尽空气质量数据的研究工作的组成部分。该数据集呈现了由马里科帕县空气质量部门（Maricopa County Air Quality Department）监测站测得的、经空间插值处理的臭氧（O3）浓度数据。臭氧（O3）是由三个氧原子结合形成的天然化合物，其结合状态并不稳定，臭氧会持续处于自然循环之中：不断生成，随后又转化为更稳定的常态双原子氧气化合物（O2），且该循环的发生速度相对较快。在地球上空6英里及以上的平流层中，天然存在的臭氧能够有效阻挡太阳发出的有害紫外线，发挥有益作用。但近地面臭氧属于污染物，也是马里科帕县山谷区域常见的棕褐色霾的主要组成成分。臭氧并非直接排放至大气中，而是通过涉及热量、阳光以及各类有毒污染物（尤其是挥发性有机物（VOCs））的复杂反应生成。挥发性有机物最常见的来源包括汽油蒸气、化学溶剂以及燃料和消费品的燃烧产物。臭氧由阳光作用于机动车与固定源排放的氮氧化物（NOx）和挥发性有机物生成，且可被输送至距排放源数百英里之外的区域。臭氧会对人类和动物的呼吸系统造成影响，同时也会影响植物的生长。