The distribution and dynamics of atmospheric pollutants are spatiotemporally heterogeneous due to variability in emissions, transport, chemistry, and deposition. To understand these processes at high spatiotemporal resolution and their implications for air quality and personal exposure, we present custom, low-cost air quality monitors that measure concentrations of contaminants relevant to human health and climate, including gases (e.g., O₃, NO, NO₂, CO, CO₂, CH₄, and SO₂) and size-resolved (0.3–10 µm) particulate matter. The devices transmit sensor data and location via cellular communications and are capable of providing concentration data down to second-level temporal resolution. We produce two models: one designed for stationary (or mobile platform) operation and a wearable, portable model for directly measuring personal exposure in the breathing zone. To address persistent problems with sensor drift and environmental sensitivities (e.g., relative humidity and temperature), we present the first online calibration system designed specifically for low-cost air quality sensors to calibrate zero and span concentrations at hourly to weekly intervals. Monitors are tested and validated in a number of environments across multiple outdoor and indoor sites in New Haven, CT; Baltimore, MD; and New York City. The evaluated pollutants (O₃, NO₂, NO, CO, CO₂, and PM_2.5) performed well against reference instrumentation (e.g., r=0.66–0.98) in urban field evaluations with fast e-folding response times (≤ 1 min), making them suitable for both large-scale network deployments and smaller-scale targeted experiments at a wide range of temporal resolutions. We also provide a discussion of best practices on monitor design, construction, systematic testing, and deployment.

中文翻译：

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用于高时空分辨率空气质量研究的固定式和便携式多污染物监测仪，包括在线校准

由于排放、传输、化学和沉积的可变性，大气污染物的分布和动态在时空上是异质的。为了以高时空分辨率了解这些过程及其对空气质量和个人暴露的影响，我们提供定制的低成本空气质量监测器，用于测量与人类健康和气候相关的污染物浓度，包括气体（例如 O ₃、NO、 NO ₂、CO、CO ₂、CH ₄和 SO ₂）和尺寸分辨（0.3–10  µm) 颗粒物。这些设备通过蜂窝通信传输传感器数据和位置，并能够提供低至秒级时间分辨率的浓度数据。我们生产两种型号：一种专为固定（或移动平台）操作而设计，另一种可穿戴便携式型号，用于直接测量个人在呼吸区的暴露量。为了解决传感器漂移和环境敏感性（例如，相对湿度和温度）的长期问题，我们提出了第一个专门为低成本空气质量传感器设计的在线校准系统，以每小时到每周的间隔校准零和跨度浓度。监视器在康涅狄格州纽黑文的多个室外和室内站点的多种环境中进行了测试和验证；马里兰州巴尔的摩；和纽约市。评价污染物（O₃、NO ₂、NO、CO、CO ₂和 PM _{2.5 ）在具有快速}e折叠响应时间（ ≤1分钟）的城市现场评估中相对于参考仪器（例如， r = 0.66 –0.98）表现良好 ，使其适合适用于各种时间分辨率的大规模网络部署和小规模目标实验。我们还讨论了有关监视器设计、构造、系统测试和部署的最佳实践。