Many cities have implemented monitoring networks that continuously measure air pollutants as part of their air quality management systems. Many of them regularly report an Air Quality Index (AQI) that is easy to interpret, and often color-coded, to warn of dangerous levels of air pollution. The information is accessible through websites, newspapers and apps. Countries define their own indices based on their own air quality standards. Therefore, they are not comparable between countries and are designed for public information purposes.
The availability of air quality monitoring is unequal both globally and regionally. This is because high quality monitors are expensive, as is the cost of training people to run and maintain monitoring networks. Even in places with good monitoring, there are discrepancies. For example, in some parts of Europe
, there are very dense monitoring networks, while in other parts the networks are less dense. In many developing countries across the world there is no official air pollution monitoring.
Investing in air quality monitoring is very important because the larger the networks are, the more information we can have for a city, region or country. This information can be invaluable for helping people understand what the air pollution levels are where they live and take action to reduce their exposure to harmful levels. It's also important for governments, to be able to make short and long-term planning decisions to reduce air pollution
In many places, private companies are developing lower-cost air quality monitors that people can install in their own homes. This is leading to networks of citizen scientists reporting on air quality and citizen led online air quality databases.
A number of international and civil society organizations, and private companies, also collect and report air quality information, often based on a combination of monitoring and satellite data. Where local information is unavailable, these can be useful resources to understand the air pollution problem in your city or country.