# A Review of Air Pollution Monitoring Technology for Ports
## 4 Summary and Prospect  
At present, whether it is a fixed monitoring station or movable monitoring equipment, according to its monitoring results, air pollution monitoring technology can be divided into continuous monitoring equipment and non-continuous monitoring equipment. Non-continuous monitoring equipment is generally a combination of samplers and laboratories for the analysis of monitoring equipment. The advantage is the low cost, and monitoring results are generally more accurate. Continuous monitoring equipment, on the other hand, is online monitoring equipment that uses various automatic analysis methods as a principle, as well as various types of air pollutant sensors. Although different principles are applied to design and combine different pollutants, continuous monitoring equipment is relatively expensive and bulky. However, with the development of the times, the monitoring of port air pollution will gradually tend to be intelligent, and various types of continuous monitoring equipment will have a wider application and development, while non-continuous monitoring equipment will be able to play a supporting role to ensure the accuracy of online continuous monitoring of port air pollutants. There are currently three areas that are more conducive to the development of port air monitoring.  
(1) In terms of monitoring methods, to reduce the high price and large size caused by the application of different principles to design online monitoring equipment, it will be a future trend to study the use of the same principle, such as DOAS, to simultaneously monitor a variety of air pollutants, such as SO\({}_{2}\), NOx, and PM, which will greatly reduce the economic costs of air monitoring when covering the whole port.  
Although many related types of research are still not mature enough and the accuracy of such equipment is not very high, with the development of technology, the accuracy, precision, and anti-interference of such monitoring equipment will be greatly improved and then used in the actual port air pollutant monitoring project.  
(2) The second is the development of more mature types of gas sensors, with their low price, strong integration, rapid response, and continuous monitoring capabilities having the advantage of a wide range of applications at present, and along with the latest iterations of technology they should also have higher monitoring accuracy, range, and anti-interference ability. The sensor-based online monitoring system has greater advantages in monitoring port air pollution. At the same time with the combination of UAV and sensors, it can also be combined with the monitoring system with the sea and port land to achieve comprehensive monitoring of air pollution in the port area.  
(3) In the monitoring mode, the combination of continuous monitoring and regular non-continuous monitoring will be a healthier mode of monitoring air pollutants in the port. The results of non-continuous monitoring can be used as a reference to check whether the continuous monitoring system is operating normally and to determine whether the components of the monitoring equipment have been damaged due to the changing environment in the port area so that the equipment can be repaired and replaced in time to provide an additional layer of protection for air pollution monitoring in the port.  
Conceptualization, Y.Y. and P.G.; methodology, Y.Y.; software, Y.Y.; validation, Y.Y. and P.G.; formal analysis, Y.Y.; investigation, Y.Y.; resources, P.G.; data curation, Y.Y.; writing--original draft preparation, Y.Y.; writing--review and editing, P.G.; visualization, Y.Y.; supervision, P.G.; project administration, P.G.; funding acquisition, P.G. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.