AQI indicates that acute exposure may cause significant harm to the public health, agencies may invoke emergency plans that allow them to order major emitters (such as coal burning industries) to curtail emissions until the hazardous conditions abate. Most air contaminants do not have an associated AQI. Many countries monitor ground-level ozone, particulates, sulfur dioxide, carbon monoxide and nitrogen dioxide, and calculate air quality indices for these pollutants. The definition of the AQI in a particular nation reflects the discourse surrounding the development of national air quality standards in that nation. A website allowing government agencies anywhere in the world to submit their real-time air monitoring data for display using a common definition of the air quality index has recently become available. Indices by location Australia Each of the states and territories of Australia is responsible for monitoring air quality and publishing data in accordance with the National Environment Protection (Ambient Air Quality) Measure (NEPM) standards. Each state and territory publishes air quality data for individual monitoring locations, and most states and territories publish air quality indexes for each monitoring location. Across Australia, a consistent approach is taken with air quality indexes, using a simple linear scale where 100 represents the maximum concentration standard for each pollutant, as set by the NEPM. These maximum concentration standards are: The air quality index (AQI) for an individual location is simply the highest of the air quality index values for each pollutant being monitored at that location. AQI bands, with health advice for each: Canada Air quality in Canada has been reported for many years with provincial Air Quality Indices (AQIs). Significantly, AQI values reflect air quality management objectives, which are based on the lowest achievable emissions rate, rather than exclusive concern for human health. The Air Quality Health Index (AQHI) is a scale designed to help understand the impact of air quality on health. It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing a behavioral change to reduce the environmental footprint. This index pays particular attention to people who are sensitive to air pollution. It provides them with advice on how to protect their health during air quality levels associated with low, moderate, high and very high health