Oops, it doesn't look like 'Air Quality Index day' is a national day..

Other days

polyamory

Polyamory Day
gallery

Gallery Day
ruby

Ruby Day
pumpkin

Pumpkin Day
azonto is acceptable

Azonto Is Acceptable Day
my little pony

My Little Pony Day
unicorn

Unicorn Day
hiv awareness

Hiv Awareness Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
eat what you want

Eat What You Want Day