States have obligations to protect against environmental harm that interferes with the enjoyment of human rights. In this respect, substantive environmental quality standards help protect human health from environmental hazards. In some cases, international organizations have set substantive environmental standards to protect human health that serve as guidelines for States to meet or exceed when adopting their own standards.
For example, the World Health Organization (WHO) published air quality guidelines in1987 (revising them in 1997 and 2005). The guidelines “are designed to offer guidance in reducing the health impacts of air pollution” based on a review of accumulated scientific evidence. The current guidelines set standards relating to a variety of common air pollutants, including particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2). With respect to NO2, the WHO guidelines set values at 40 micrograms per cubic meter or 21.2 parts per billion (ppb) as an annual mean, and 200 micrograms per cubic meter or 106.3 ppb as a one-hour mean concentration. As a comparison, the United States has set its annual mean standard at 53 ppb and its 1 hour mean at 100 ppb, while Australia has set its annual mean at 30 ppb and its hourly mean at 130 ppb.
In some cases, the World Health Organisation also recommends management practices to address environmental hazards. For example, the WHO guidelines for safe recreational waters, such as beaches, lakes, and rivers, not only propose, where feasible, standards for a wide range of contaminants, such as faecal pollution, free-living microorganisms, microbial aspects of beach and sand quality, and algae and cyanobacteria, but also recommend a variety of practices to reduce risks of human exposure, like awareness raising, monitoring for contamination, and management practices to reduce conditions where risks can occur.
The 2005 WHO air quality guidelines are at: http://whqlibdoc.who.int/hq/2006/WHO_SDE_PHE_OEH_06.02_eng.pdf?ua=1 and safe recreational water guidelines: http://www.who.int/water_sanitation_health/bathing/srwg1.pdf; the US national ambient air quality standards can be found at: http://www3.epa.gov/ttn/naaqs/criteria.html; Australia’s air pollution standards can be found at: http://www.environment.gov.au/protection/publications/factsheet-national-standards-criteria-air-pollutants-australia.