Качество воздуха в Ханой

Where does IQAir AirVisual get its data from?

IQAir AirVisual reports from governmental and non-governmental air monitoring stations. For each station, it always lists the data source, contributor and location. IQAir AirVisual does this to be fully transparent and to give its users a choice as to which data they want to follow.

It mostly reports from ground-based stations, which are the most accurate. However, if a particular location doesn’t have any stations and people ask IQAir AirVisual for air quality information, it can use data modeling from satellite imagery and weather patterns to estimate air quality. In these cases, it writes next to the AQI number that this data is an estimated figure.

How does IQAir AirVisual calculate the Air Quality Index value?

Each pollutant has both a concentration and Air Quality Index (AQI) value. IQAir AirVisual takes the concentrations of pollutants reported by a station and calculates each pollutant’s AQI value. The pollutant with the highest AQI level, or risk to health, is deemed the "main pollutant." The main pollutant's AQI is the overall Index value.

A city's AQI is an average of all the stations’ AQIs in that city - IQAir AirVisual takes the median value, not the mean, to avoid one or two stations that may be reporting significantly higher values affecting the city’s overall AQI.

It uses the United States’ AQI, which is one of the world’s most stringent.

How often is the AQI updated?

IQAir AirVisual updates it in real-time, not on a 24-hour rolling average. This is so people have up-to-date information and can act to protect themselves when there are sudden pollution spikes.

How accurate is IQAir AirVisual’s data?

The data IQAir AirVisual reports – both from governmental and non-governmental monitors – is constantly monitored by its Artificial Intelligent (AI) system, which flags what it considers inappropriate data. Should the data still be in doubt, it offers users the possibility to report a potential problem with a station. This ensures double data validation: from the system and from the community. IQAir AirVisual believes that it is the air quality data provider that has done more than any other to ensure data accuracy and reliability.

More details on IQAir AirVisual’s validation and calibration processes are available here.