(Air Quality Data provided by Environment Canterbury)
(See health implications table below)
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PM2.5 is measured by Environment Canterbury. Values are converted from micrograms per cubic metre to AQI levels using the EPA standard. PM2.5 refers to atmospheric particulate matter (PM) that has a diameter of less than 2.5 micrometers, which is about 3% the diameter of a human hair. Particles in this category are so small that they can only be detected with an electron microscope. Owing to their minute size, particles smaller than 2.5 micrometers are able to bypass the nose and throat and penetrate deep into the lungs and some may even enter the circulatory system. Studies have found a close link between exposure to fine particles and premature death from heart and lung disease. Fine particles are also known to trigger or worsen chronic disease such as asthma, heart attack, bronchitis and other respiratory problems. |
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PM10 is measured by Environment Canterbury. Values are converted from micrograms per cubic metre to AQI levels using the EPA standard. PM10 particles (often described as coarse particles) are smaller than 10 micrometres (0.01 mm) in diameter. High levels of PM10 particles in the air can irritate the eyes and throat. People with existing heart or lung conditions (including asthma) can experience an increase in symptoms, including wheezing, chest tightness and difficulty breathing. Common sources of PM10 particles include sea salt and pollen, and combustion activities such as motor vehicles and industrial processes. Dust from unsealed roads is a major source of PM10 particles. |
| AQI | Air Pollution Level | Health Implications | Cautionary Statement (for PM2.5) |
|---|---|---|---|
| 0 - 50 | Good | Air quality is considered satisfactory, and air pollution poses little or no risk. | None |
| 51 - 100 | Moderate | Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution. | Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion. |
| Unhealthy for Sensitive Groups | Members of sensitive groups may experience health effects. The general public is not likely to be affected. | Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion. | |
| Unhealthy | Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects. | Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion | |
| Very Unhealthy | Health warnings of emergency conditions. The entire population is more likely to be affected. | Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion. | |
| 301 + | Hazardous | Health alert: everyone may experience more serious health effects. | Everyone should avoid all outdoor exertion. |