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World air quality (AQI) ranking
Your questions answered, on IQAir's 2018 World Air Quality Report
Changelog: 2018 World Air Quality Report
Air quality ranking disclaimer
Why are the WHO Air Quality Guidelines used when different countries have different ambient air quality requirement?
What are some of the major sources or causes of ambient air pollution?
Since data measured by AirVisual monitors are used in the ranking, how accurate are AirVisual data?
Why is the US Air Quality Index used in the ranking?
How precise is the ranking?
How is historical data being incorporated in the ranking dataset?
Is missing data from stations common? How is the missing data treated in this ranking and which countries have bad data quality?
What is the data availability rule in the ranking?
How is the ranking air quality data collected, processed and calculated?
What are the steps taken to ensure the quality of data of the ranking?
What are the data sources for this air quality ranking?
How are the yearly PM2.5 yearly measurements for country/region calculated?
Why is PM2.5 chosen for this ranking?
Why is the air quality ranking data different from governmental/official data?
Why are some cities and countries not listed in this air quality ranking?