# IoT and Blockchain Integration: Applications, Opportunities, and Challenges
## 3 Applications and Categories of IoTs  
IoT has been utilized in various areas, from home to health, education, and agriculture industries. As an introduction, we highlighted the coarse evolutionary events of IoTs and different use cases. However, in this section, we instantiate major applications of IoTs under seven categories.  
1. Climate and Environmental (Aquatic/Terrestrial) IoT: Environmental IoTs are composed of sensors employed for different purposes, such as detecting pathogens, chemicals, gas, temperature, and(or) other variables in an environment, such as land or water bodies [21]. For instance, regulatory bodies such as Environment Protection Agency (EPA) often employ IoT to monitor the risk factors that affect human and environmental health. Similarly, industries based on land and water resources have benefited from the IoTs for various business needs. For instance, climate and environmental IoTs have been used for real-time monitoring and forecasting of weather, and climatic conditions in an area [8].
2. Forest and Agricultural IoT: Applying IoTs has proved profitable in forestry, and crop/animal farming [5,22,23]. Chiefly, IoT systems have been used for managing and monitoring several aspects of farming, such as irrigation, pest control, weed control, and crop density monitoring, among others.
3. Industrial IoT: The use of IoTs has been profitable in industries of varying kinds, such as hospitals [2], manufacturing industries, and retail and whole-shale markets, among others. Everyday use cases of an industrial IoT include remote condition monitoring, digital work instructions, predictive mainteisce, and disaster management. Using industrial IoTs brings several benefits, such as maximizing revenue, reducing time to market, and lowering operational costs.
4. Smart Home IoT An IoT find(s) is one of its most popular applications inside a home setting. Automating lighting, sound, and kitchen work such as cooking and washing are automated by using different connected devices. Controlling and maintaining home climate can also be performed effectively using sensors such as thermostats [1,4,21].
5. Wearable IoT: Wearable IoT comprises wearable technologies such as Fitbit, Holter monitor, personal alarm devices, smartwatches, etc. The sensing devices have become so small that they have been integrated into normal clothing items such as bras or vests, caps, shoes, and travel/school backpacks [21,24,25]. Wearable IoT has helped monitor personal health and supports remote health services [3].  
* Smart City IoT: Smart city IoTs are an extended version of the smart home IoT [1]. It comprises many sensor technologies to sense an urban environment, streets, highways, traffic, and vehicle mobility. Smart retail shopping, intelligent health services, and smart parking are also an integral part of a smart city ([[https://en.wikipedia.org/wiki/Smart_city](https://en.wikipedia.org/wiki/Smart_city)]([https://en.wikipedia.org/wiki/Smart_city](https://en.wikipedia.org/wiki/Smart_city)) (accessed on 22 July 2022)) [4].
* Vehicular IoT: Vehicular IoT can be considered one of the components of a smart city IoT. Sensors that collect data from terrestrial and aerial vehicular devices constitute vehicular IoT. The data may be helpful to route the vehicular devices efficiently or may be helpful to collect environmental data such as temperature and humidity. For instance, United Parcel Service (UPS), a shipping company, deploys sensors in its transport vehicles to collect data such as mileage, speed, fuel cost, etc., for big data analysis [26; 27]. Unmanned aerial vehicles (UAVs) also use different sensor data to optimize their route and operations to support \"collaborative autonomous driving, and advanced transportation [28]\".