Indoor air quality measurements of formaldehyde using low cost sensors

甲醛是一种严重的健康风险，国际癌症研究机构（IARC）将甲醛列为人类致癌物。对于室内空气有严格的甲醛暴露指南（80 ppb WHO），在国家一级甚至可以更低（例如，到2023年达到8 ppb）。人们在家中接触到来自各种来源的甲醛。这些包括许多日常用品，如化妆品，家具和洗涤剂。随着甲醛对健康的威胁越来越大，对家庭和其他室内空间进行监测变得越来越重要，以便居民能够采取行动尽量减少其暴露。甲醛通常通过现场批量采样和外部分析实验室的非现场定量进行测量。这些程序昂贵、耗时，需要熟练的人员，并且不允许现场监测。环境空气中的甲醛测量需要监测仪的ppb级检测灵敏度。此外，当用于室内空气监测时，它们必须有选择性地检测含有数百种化合物的环境空气中ppb级的甲醛浓度。目前市场上的产品要求消费者为了成本而牺牲灵敏度和选择性;低成本的传感器无法达到20 ppb的低检测限的目标，或者对乙醇等常见化学物质产生假阳性。应用Nanodetectors室内空气质量监测系统（AND-IAQ 01），可以检测ppb级的甲醛。它还测量主要的室内污染物，包括二氧化碳，颗粒物（PM2.5）和总挥发性有机化合物（TVOC）。该器械符合UKCA（英国合格评定）标志所需的所有相关协调和指定标准的基本要求。伦敦政府化学家（LGC）将通过将设备暴露于合成空气/甲醛混合物（低至20 ppb）来评估我们的系统性能，并评估混杂气体的影响。

Formaldehyde is a significant health risk, and International Agency for Research on Cancer (IARC) classifies formaldehyde as a human carcinogen. There are stringent formaldehyde exposure guidelines that exist for indoor air (80 ppb WHO) that can be even lower at the national level (e.g., France 8 ppb by 2023). People are exposed to formaldehyde from a variety of sources inside their homes. These include many everyday products, such as cosmetics, furniture, and detergents. With the growing health threat that formaldehyde poses, it is becoming more critical to monitor homes and other indoor spaces so that inhabitants can take action to minimise their exposure.Formaldehyde is usually measured by on-site batch sampling and off-site quantification in an external analytical laboratory. These procedures are expensive, time-consuming, require skilled personnel and do not allow on-site monitoring. Formaldehyde measurement in ambient air requires ppb-level detection sensitivity from a monitor. Furthermore, when used in indoor air monitoring, they must be selective to detect ppb-level formaldehyde concentrations in ambient air containing hundreds of compounds. Current products on the market require consumers to sacrifice sensitivity and selectivity for cost; low-cost sensors do not meet the goal of a low detection limit of 20ppb or give false positives to common chemicals such as ethanol.Applied Nanodetectors indoor air quality monitoring system (AND-IAQ01), can detect formaldehyde at ppb levels. It also measures key indoor pollutants, including carbon dioxide, particulate matter (PM2.5), and total volatile organic compounds (TVOC). This device complies with the essential requirements of all relevant harmonised and designated standards required for The UKCA (UK Conformity Assessed) marking. The product is commercially available via key specialist suppliers.The London Government Chemist (LGC) will evaluate our system performance by exposing the device to synthetic air/formaldehyde mixtures (down to 20 ppb) and evaluate the effect of confounding gases.