Bad Air Days in Johnson County, Indiana: 0 a Year

0 bad air days a year

Rare: among the cleanest-air counties EPA monitors. Ranked 962 of 996 monitored counties, where 1 is worst.

What to buy, and what not to

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

The worst days on file

Date	AQI	Main pollutant
2016-06-11	100	Ozone
2016-05-23	80	Ozone
2017-06-05	80	Ozone
2017-06-09	80	Ozone
2016-04-17	77	Ozone

Most days, not the worst ones

Across 420 monitored days from 2016 to 2017, the air in Johnson County rated Good on 89% of them, more often than the 72% typical of monitored counties, and Moderate on 11%. The median day sat at AQI 39; one day in ten went above 52.

The pollutant setting the AQI on an ordinary day here:

ozone100%420 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Median AQI	Highest AQI
2017	237	214	23	0	39	80
2016	183	158	25	0	38	100
2015	179	158	21	0	39	90
2014	176	170	6	0	37	71
2013	180	159	21	0	42	93
2012	182	109	64	9	47	140
2011	178	129	49	0	44	100
2010	183	132	49	2	44	105

Nearby counties on file

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.