Monitor the air quality around you. Get notified when the air quality drops so you can move indoors or turn on your air purifier. NEW - a widget for your home screen! See information about the top pollutants in your area: PM2.5, PM10, NO2, SO2, CO, O3... Powered by Air Quality Index https://aqicn.org/ PM2.5 + PM10 Airborne particulate matter (PM) is a complex mixture of many chemical components (solids and aerosols). Particles with a diameter of 10 microns or less (PM10 and PM2.5) can be inhaled into the lungs and cause adverse health effects. NO2 Nitrogen dioxide (NO2) is a highly reactive gas produced by the combustion of fossil fuels. NO2 irritates the airways in the human respiratory system and can aggravate respiratory diseases (especially asthma). NO2 reacts with other chemicals in the air to form particulate matter and ozone. SO2 Sulfur dioxide (SO2) is a colorless gas produced by the combustion of fossil fuels and volcanic activity. SO2 irritates the skin and mucous membranes of the eyes, nose, throat, and lungs. CO Carbon monoxide (CO) is a colorless gas produced by the incomplete combustion of fossil fuels. It reduces the amount of oxygen that can be transported in the bloodstream. O3 Ground-level ozone (O3) is a major component of smog. It irritates the respiratory system and increases the lungs' susceptibility to infections, allergens, and other air pollutants.