Erie Vital Signs

Air Quality: Air Quality

Recent Performance

Air quality has been improving in the Erie area over the long term. In the most recent five years, the EPA’s Air Quality Index has been in the “good” range (which is the best category) 61% of the time compared with only 44% of the time in the early 1980s. Erie has had only 0.1% “unhealthy” days in the last five years (and none in the last two years), and no “very unhealthy” days since 1988. In the period from 1980-84, Erie experienced days that were “unhealthy for sensitive groups” 16.1% of the time—nearly one day in six. But from 2010 to 2014, the same category occurred only 0.9% of the time, less than one in a hundred.

A lower AQI is better, and the “good” category includes readings in the 0 to 50 range. In the last two years, Erie’s AQI has averaged 26.3 and 27.6, compared with annual averages for 1980 and 1981 of 59.3 and 54.9. Erie’s median value for 2014 was just 12.0.

However, the picture is not all roses. Compared to its peers for 2014, Erie’s 65.5% of “good” days is below the peer average of 74.3%, and is worse than 10 of the 13 peers.

The Basics

This indicator reports the percentage of monitored days for which the Environmental Protection Agency’s Air Quality Index (AQI) was in the “good” range, rather than “moderate”, “unhealthy for sensitive groups”, “unhealthy”, or “very unhealthy”. According to the EPA: “the Air Quality Index is an indicator of overall air quality, because it takes into account all of the criteria air pollutants measured within a geographic area.”

Why It's Important

Air quality is obviously an important factor in the level of health of local residents. It can also be a location factor for firms who rely on clean air for their businesses, or because they may add pollution to the local environment and are sensitive to the AQI level.

The Details

The AQI monitors the following six criteria air pollutants:
* carbon monoxide
* nitrogen dioxide
* ozone
* sulfur dioxide
* particulate matter smaller than 2.5 micrometers
* particulate matter smaller than 10 micrometers

A daily index value is calculated for each air pollutant measured. The highest of those index values is the AQI value, and the pollutant responsible for the highest index value is the "Main Pollutant." For Erie, 2.5 micrometer particulates and ozone were the Main Pollutants 99.4% of the time in 2014.

The EPA rates air quality into five categories:
* Good: AQI value 0 through 50.
* Moderate: AQI value 51 through 100.
* Unhealthy for Sensitive Groups: AQI value 101 through 150.
* Unhealthy: AQI value 151 through 200.
* Very Unhealthy: AQI value 201 or higher. This includes the AQI categories very unhealthy and hazardous. Very few locations (about 0.3% of counties) have any days in the very unhealthy or hazardous categories.

There is typically an AQI rating for every day for each area, but data for some days are missing. For that reason, the EVS Air Quality Indicator reports the percentage of days each year for which the EPA has data for the area.

The Nitty-Gritty Details

Air Quality Index Report description


None on EVS, but the EPA reports the number of days each pollutant is the “Main Pollutant” and the EPA website provides Air Quality Statistics Reports which includes data on all measured pollutants—up to 13 of them--and the maximum value at any monitoring site in the area during the year, relative to national standards.

Peer Areas

Data are available for the 13 standard Peer Areas.


Annual (but the EPA has daily information on their website)


U.S. Environmental Protection Agency, Air Quality Index Report
* Data
* Description

Other Related Information

content management, website design, e-commerce and web development services in Erie, Pennsylvania