Knowing the information will help me decide where/when to go, and whether I should bring some air-related equipment (mask, air purifier, etc.).

What I have unsuccessfully tried so far:

  • Wikipedia typically doesn't show the average air quality during a given month/week/day based on historical data.
  • 4
    I can't imagine how knowing average data over the last X years helps you deciding whether you need to wear a mask tomorrow. Despite your first paragraph, I find this question completely off-topic.
    – littleadv
    Commented Sep 13, 2022 at 23:55
  • 1
    @littleadv useful to decide and prepare a trip ahead of time. Eg I don't want to commit to go to some place in two months if it's known to be typically very polluted then. Commented Sep 14, 2022 at 0:19
  • 2
    I’m voting to close this question because it's not about travel.
    – Midavalo
    Commented Sep 14, 2022 at 3:28
  • 1
    @Midavalo preparing for the local conditions is an important part of traveling. Many questions have been asked in that spirit eg travel.stackexchange.com/q/61616 Commented Sep 14, 2022 at 3:43
  • 1
    The American Lung Association analyses data from official air quality monitors to compile the State of the Air report, lung.org/research/sota Its reports are searchable by state, county, and metropolitan statistical area
    – Traveller
    Commented Sep 14, 2022 at 8:42

1 Answer 1



Plot daily AQI values for a specific location and time period. Each square or “tile” represents one day of the year and is color-coded based on the AQI level for that day. The legend tallies the number of days in each AQI category.

enter image description here

They also make all the data available as a CSV file for each year, so one can compute the daily/weekly/monthly trend by averaging over several years.

airnow.gov gives the air quality for a given day in different locations in a US state in the past. Downside: doesn't give directly a clear daily/weekly/monthly trend.

enter image description here

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