Indicator # 1 - Date when the pollen season started by pollen source              Print PDF

Pollen Risk Communication Message: Pollen grains are released by trees in the spring, different types of grass in summer and a variety of weeds in fall.  Ragweed pollen is also released in the fall, but it is more allergenic than other pollen types.  Because of climate variability we now know that higher temperatures and more carbon dioxide result in increased pollen in the air.  Children and older adults who have asthma, allergic rhinitis or other respiratory diseases have more severe allergic reactions as total pollen grains in the air increase or when ragweed pollen is produced in the fall.  Pollen influenced allergic and respiratory reactions are even worse in the summer when ozone and/or fine particulates in the air are also higher.  Research has shown that higher pollen levels increase emergency department visits and inpatient hospitalizations due to asthma, hay fever and other respiratory diseases.  Prevention efforts can include seeing a health care provider before the start of the pollen season or when breathing problems become worse when pollen spores increase.  Persons can decrease their exposure to pollen by not going outdoor, staying in a home or automobile with the windows closed and the air conditioner on, taking a shower to remove pollen from around the nose and mouth, and changing clothes.  For more information about pollen and health see the MTN pollen indicator page.

 Data sources for this indicatorà

  • Determine the first day, recorded as mm/dd/yyyy, in which counting began for any pollen source in the calendar year.
  • The first day should be recorded for the first pollen reading, no matter the type of pollen recorded, as well as for trees, grasses, weeds, and ragweed, separately.
  • Note: In the event a pollen station operates year-round, the first day should be January 1.  If the first day when the pollen readings were reported was after the first of January, then the date is the start of the pollen season.  




Table: Start date of pollen source by year.


    1997 1998 1999 2000 2001 2002 2003 2004
Total 27-Mar 10-Mar 18-Mar 2-Mar 20-Feb 21-Feb 19-Mar 3-Mar
Trees 27-Mar 10-Mar 18-Mar 25-Feb 20-Feb 20-Feb 18-Mar 3-Mar
Grass 28-Apr 13-Apr 26-Apr 7-Apr 26-Apr 1-Apr 18-Apr 7-Apr
Weeds 10-Jun 16-Apr 23-Apr 3-Apr 26-Apr 1-Apr 18-Apr 19-Apr
Ragweed 15-Aug 12-Aug 16-Aug 8-Aug 8-Aug 11-Aug 15-Jul 4-Aug

2005 2006 2007 2008 2009 2010 2011 2012
Total 8-Mar 10-Mar 14-Mar 3-Mar 27-Feb 11-Mar 18-Mar 7-Mar
Trees 8-Mar 10-Mar 14-Mar 19-Feb 27-Feb 11-Mar 18-Mar 7-Mar
Grass 18-Apr 14-Apr 3-Apr 11-Apr 6-Apr 6-Apr 7-Apr 4-Apr
Weeds 27-Apr 11-May 25-Apr 15-May 27-Apr 29-Apr 5-Apr 10-May
Ragweed 3-Aug 9-Aug 6-Aug 5-Aug 10-Aug 9-Aug 28-Jul 3-Aug