This study examined the observed relationship between ozone (O₃) and temperature using data from 1995 to 2020 at 20 cities across the United States (U.S.) that exceed the O₃ National Ambient Air Quality Standard (NAAQS). The median slope of the O₃ versus temperature relationship decreased from 2.8 to 1.5 parts per billion per degrees Celsius (ppb °C⁻¹) in the eastern U.S., 2.2 to 1.3 ppb °C⁻¹ in the midwestern U.S., and 1.7 to 1.1 ppb °C⁻¹ in the western U.S. O₃ in the eastern and midwestern U.S. has become less correlated with temperature due to emission controls. In the western U.S., O₃ concentrations have declined more slowly and the correlation between O₃ and temperature has changed negligibly due to the effects of high background O₃ and wildfire smoke. This implies that meeting the O₃ NAAQS in the western U.S. will be more challenging compared with other parts of the country.

中文翻译：

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观测到的美国​​城市未达标地区臭氧与温度之间的关系

本研究使用 1995 年至 2020 年在美国 (US) 超过 O ₃国家环境空气质量标准 (NAAQS) 的20 个城市的数据，检查了观察到的臭氧 (O ₃ ) 与温度之间的关系。O ₃与温度关系的中值斜率从美国东部的每摄氏度 (ppb °C ^-1 ) 的2.8 至 1.5 ppb °C ^-1，美国中西部的2.2 至 1.3 ppb °C ^-1以及 1.7 至 1.1由于排放控制，美国西部的ppb °C ^-1 O ₃在美国东部和中西部与温度的相关性降低。在美国西部，O ₃由于高背景 O ₃和野火烟雾的影响，浓度下降得更慢，O ₃与温度之间的相关性变化可以忽略不计。这意味着与美国其他地区相比，在美国西部满足 O ₃ NAAQS 将更具挑战性。