Historical air quality monitoring trends and analysis for National
Hourly Avg, Past 2 Weeks
The average number of devices reporting USG or worse over the past two weeks of hourly data
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Hourly Peak, Past 2 Weeks
The highest number of devices reporting USG or worse in a single hour in the past two weeks.
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Trend
Compares the average hourly USG+ device count from the first half of the available data to the second half. A rise of more than 10% is Worsening; a drop of more than 10% is Improving; otherwise Stable.