Historical Air Quality Data​

Status of Ozone Pollution in Maryland

The Department has developed maps to help you visualize Maryland's air quality improvements. The maps illustrate how lower ozone levels have led to smaller problem areas. Ozone

 

8-Hour Ozone Exceedance Days

Excel Data The annual list of the 8-hour ozone concentrations exceeding the 2008 health-based National Ambient Air Quality Standard is provided below.  Click on the appropriate check mark to download the data in Excel format.  Be advised that the counts of days reflect all monitors that are part of the non-attainment area (NAA); however, only Maryland data collected by the Department and the EPA Clean Air Status and Trends Network (CASTNET) are provided in the Excel file.  A map of NAAs shows the Maryland NAAs and surrounding jurisdictions.

Historical air quality data is also accessible at  Clean Air Partners, EPA Air Data,  and other data resources listed below. 

Number of Days 8-Hour Ozone Concentrations Exceeded 2015 Health-Based Standard

  Baltimore, MD NAA Washington, DC-MD-VA NAA Philadelphia-Wilmington-Atlantic City, PA-DE-MD-NJ NAA State-wide Excel
2018 16 9 20 16 checkmark
2017 9 8 14 17 checkmark
2016 21 13 23 26 checkmark

2015

15 14 29 20 checkmark
2014 5 10 14
11
2013 9 12 13 19
2012 35 34 41 42
2011 35 37 30
46
2010 50 48 47 61
2009 16 12
24 19
2008 40 37 41 49

Notes: "NAA" denotes non-attainment area, EPA CASTNET data are included since 2011.

Table reflects the 2015 70ppb ozone standard.

 

Data Resources