PM25.im - PM2.5 Index Query

PM25.im provides real-time PM2.5 American standard AQI air quality index queries for cities across the country. The real-time PM2.5 concentration in each city is sourced from authoritative data from the China Environmental Monitoring Station of the Ministry of Environmental Protection and converted into the American standard AQI index in real-time

Features of this website

First-hand data

The data source is not from other site APIs, with the fastest update time across the entire network. Currently, it provides real-time PM2.5, PM10 data from over 2000 monitoring sites in 408 cities across the country, as well as US standard AQI queries; This website defaults to using IP address location. In case of inaccurate location, please select a city: click here to browse all cities.

The concentration units of PM2.5 and PM10 are μ g/m ³, which is micrograms per cubic meter, reflecting the real-time concentration of pollutants in the air. The data is released in real-time by the China Environmental Monitoring Station.

American Standard AQI

All AQI data on this site are based on US standards, converted to US standard AQI using real-time PM2.5 and PM10 concentrations according to the formula on the US Environmental Protection Agency website. Strictly speaking, the AQI index is calculated based on the 24-hour average concentration of pollutants and has a lag. Therefore, this website calculates the air quality index in real-time based on the current major pollutants PM2.5 and PM10 in China.

Definition of AQI

The Air Quality Index (AQI) is an index that quantitatively describes the condition of air quality. The larger the value, the higher the level and category, and the darker the color, the more severe the air pollution situation and the greater the harm to human health.

What is the difference between the national standard AQI and the American standard AQI

Simply put, the American standard AQI is more stringent, but when the air quality is poor and the PM2.5 concentration is high, the national standard and American standard AQI values are completely consistent; When the PM2.5 concentration is low, there is a significant difference between the US standard AQI and the Chinese standard AQI. This website provides American standard AQI for the convenience of users to view and does not constitute any air quality recommendations.

Upgrade log

Repair local monitoring data in Beijing, Chengdu, and Chongqing on January 26, 2021

On January 16, 2018, the connection mode was changed to HTTPS, and data transmission was fully encrypted (indicated by the small lock icon on the browser) to prevent operator hijacking; Considering that relying solely on IP positioning in mobile network environments may inevitably lead to errors, such as in data roaming situations where the IP address location does not match the user's location, GPS positioning methods have been added (requiring the user to click on the homepage positioning icon to agree to the positioning request, which is not enabled by default, and this site does not save any visitor information)

On January 10, 2018, the number of monitoring points in Chengdu increased to 37, and the IP database was updated for more accurate positioning

On January 8, 2018, data from Hainan Province's directly administered counties and cities was added, and the number of monitoring stations in Shanghai increased to 56

On January 5, 2018, real-time data was added for Hong Kong and Taiwan (including monitoring stations in Taipei, Kaohsiung, and other places)

Optimize data display logic on December 30, 2017, hiding outdated data that is not updated in a timely manner; Add data queries for provincial control monitoring points in some provinces; Provide urban weather information and air quality forecasts;